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Serj22
11-15-2014, 02:14 PM
I have been working for the last 4 or so months completing this project. I turbocharged a slant six in my 1968 Dodge Dart. I have literally built the entire setup in the driveway.

I am searching for answers on electronics and a few more tuning questions and happened across this forum.

This is a daily driven car, and as such, it has been built with whatever safety and detonation limiting factors I can have. Right now - one of those - limiting the timing advance to 18* seems to be hurting performance when you're really pushing it. This car is already a rocket compared to what it was though, it's just that it can be better I think.

The setup is a 68 Slant, all internal components are exactly factory. The head has been rebuilt, brand new valves, and surface shaved - not decked to anything significant - to keep the compression similar. I built a J-pipe and downpipe myself, and run a .50 trim t3/t4 style turbocharger on it, blown through an intercooler then a Holley 350 with Hangar18 modifications completed, and a cut off choke-tower. The distributor is a stock points type, converted to electronic ignition, then I welded the governor throws clsoed a little to only allow 8* advance, then set initial timing to 10* and left the vacuum advance hooked up. In the future I'll put a volvo 240t vacuum/boost unit on it instead after I finish sorting that out. I have an MSD6 ALN to put on the car if need be, but right now, it's not in or hooked up, I'm just utilizing the Pertronix ignition.

There's a walbro 255lph electric pump feeding it through a boost referenced regulator with a return up front in the engine bay.

Right now I'm pushing 8 pounds of boost, initial set of 4psi fuel pressure, that raises 1:1 with boost pressure. It also runs very smoothly at a 14.5 AFR in cruise, 22 with the throttle closed and a solid 11.8 when at WOT.

I just dyno tested it, and am really really trying for a solid 200RWHP over the stock 95rwhp. At 8psi thought, it seemed to stop pulling after 3500RPM that i think is due to something in the ignition, or perhaps the wrong plug gap or something. It made 164rwhp and 234'lbs of torque @3600rpm. Basically I think it should be better at those numbers, so I want to crank the boost to 10, and see what other adjustments i can make to hit 200 without making the boost to out of hand. 10 is really where I want to stop on a daily driver. Basically I'm asking for advice on what i can do to milk that extra 40whp and maybe improve on what I have, while still leaving the slant itself "stock."

http://i43.photobucket.com/albums/e356/serj22/Turbo%20225/GOPR0087_zpscdbaff43.jpg (http://s43.photobucket.com/user/serj22/media/Turbo%20225/GOPR0087_zpscdbaff43.jpg.html)

http://i43.photobucket.com/albums/e356/serj22/Turbo%20225/GOPR0094_zpsc6aa70e3.jpg (http://s43.photobucket.com/user/serj22/media/Turbo%20225/GOPR0094_zpsc6aa70e3.jpg.html)

http://i43.photobucket.com/albums/e356/serj22/Turbo%20225/hdrain3_zpsfd1569b7.jpg (http://s43.photobucket.com/user/serj22/media/Turbo%20225/hdrain3_zpsfd1569b7.jpg.html)

http://i43.photobucket.com/albums/e356/serj22/IMG_20140913_084415_zpsc8ce95f9.jpg (http://s43.photobucket.com/user/serj22/media/IMG_20140913_084415_zpsc8ce95f9.jpg.html)


https://www.youtube.com/watch?v=HElZ4DB49k0

Vigo
11-15-2014, 03:40 PM
I'm a little weak on the subject of how vacuum and mechanical advance interplay, but im assuming that if you are in boost your vacuum advance is giving 0 advance, so your total timing in boost will max out at 18 degrees?

If that is true, it seems very low. If it were me, i would build a det-can or knock listening setup through headphones or something like that and see how much timing you can get away with on your octane level. It may be safer to turn the boost down to a very low number when first trying this until you are confident your 'mic' works and you know what you are listening to.

Serj22
11-15-2014, 03:55 PM
I'm a little weak on the subject of how vacuum and mechanical advance interplay, but im assuming that if you are in boost your vacuum advance is giving 0 advance, so your total timing in boost will max out at 18 degrees?

If that is true, it seems very low. If it were me, i would build a det-can or knock listening setup through headphones or something like that and see how much timing you can get away with on your octane level. It may be safer to turn the boost down to a very low number when first trying this until you are confident your 'mic' works and you know what you are listening to.

Yes, on boost the vacuum advance completely drops off leaving it at 18 degrees. This is limiting as you say but pretty much everyone I spoke to that has done their own slanted turbo has agreed that 18 is as high as it should be on any boost. My thought is with the Volvo unit (which I already have) I can tweak it so that I can pull maybe 26 advanced, and as the boost pressure raises, it will retard the distributor timing. It's off of a volvo240t from the 80s, and is right now attached to an electronic mopar slant six distributor. Once I get it apart I'll be able to weld the arm from the old pod to this one and hook one side to the vacuum and the other to the charge pipe reference, and hopefully that would ratard as pressure went up and put me somewhere near 18 as the boost hit 10psi.

The other thing i wanted to experiment with is spark plug distancing and temperature to possibly control some ignition timing as well, but it's only stuff i read about - not really used at all. I'm running premium, which I believe is 91 here. I don't remember.

I've never heard of a det can or having a mic setup - I'll have to look in to that. Since strapping a turbo to a slant is not widely done, a lot of my setup is based on others' builds and shying away from things they did that failed.

Vigo
11-15-2014, 06:12 PM
Well, unless the car made peak power at 3600 rpm before the turbo because of the head/manifolds/cam (which is possible but highly doubtful), then it seems like it MUST be in the ignition timing because you know that your AFR is good.

The only exception i can think of to that would be if, because of the vagaries of inline-6 manifold design, some of your cylinders were actually much lower on power than others due to fueling differences. I would think that would show up on a plug read if done properly, or you could take a stab at it by pointing an IR pyrometer at each exhaust port on the exhaust manifold while the engine is running under boost (which is probably pretty difficult to do because you'd probably need the dyno again and im not sure all the exhaust ports can be shot with a point and shoot pyrometer). But, if anyone else has turbo'd their slant with the same intake manifold they should have had the same issue or something similar.

The only way plug gap would have a major effect on power was if it was too big and was blowing out under boost which would probably show up as a grainy/choppy power line on the dyno graph.

Also, which displacement is your slant?

Serj22
11-15-2014, 06:50 PM
mine is the larger slant. 225 cubic inch. I've not heard of others having issues under boost like this using the same manifold. A lot of people move straight for the 4bbl carb intake though, wheras I think this 2 is adequate. It should allow enough CFM through it as it is rated for 350. On a 225 cubic inch, it only takes a little more than 300cfm to get it over 4k. 5k is the limit with a slant though. I think you are on to something with the timing, but the problem is what to do about it and still keep it safe? And I think the idea you have of being able to listen to knock is the only way to go.

Here's the graph from that Dyno Pull video:
http://i43.photobucket.com/albums/e356/serj22/dynoresults_zpse1b39b87.jpg
IF you look at one run the RPM dropped off significantly at 3700 rpm. Also if you look near the peak of every run it's kind of a scribbly line. Is that what you mean by the choppy line?

Vigo
11-16-2014, 01:26 PM
It looks like the dyno operator only took one pull past ~3700 rpm? Why was that? I cant hear in the video if anything nasty was happening that made them back off, but the dyno plot does make it look like it was starting to break up right at the peak torque rpm. Could be spark blowout or minor detonation. Not sure if it's coincidence or not, but the one pull that went all the way to ~5k rpm with a pretty clean plot on the dyno graph also had a slower torque rise and if you look you can see that it's actually substantially lower at the rpm where the previous pulls were having issues. Since the torque line corresponds with cylinder pressure i am thinking you were getting either spark blowout or detonation at the peak torque rpm.

The easy way to tell which it is would be to close up your plug gaps to .020 and see what changes. If nothing changes, it's probably starting to detonate at that rpm which you will be able to hear with a knock-listening mic setup which i think would be the next step after trying the plug gap change.

It does look like even if everything went right that you are 'naturally' peaking power at 4000 rpm. If you dont plan to change that with cam/manifold changes i would consider running a 2stg boost control setup where you go to a higher boost level at about 4200 rpm using a second boost controller, a solenoid, and an rpm switch. Those cheap adjustable shift lights on ebay/amazon can be a good way to get an adjustable rpm switch for this. If you have an internal wastegate with an adjustable rod on the outside, you could adjust your minimum boost level to ~8 via the rod and then use a solenoid with only one boost controller to up the boost as the VE goes down to extend the powerband and up your peak HP number a lot. Torque, cylinder pressure, and detonation are all pretty closely correlated in the sense that engines are most sensitive to detonation at the torque peak and less so as the rpm rises and ve/torque falls. If your engine can make 230tq at 3600 rpm before running into detonation, you should be able to use more boost to keep the engine making close to 230 torque higher into the rpm range which equates to more horsepower. There are potential issues of heat gain if your turbo compressor becomes inefficient or your cooling system cant shed heat fast enough at higher rpm but your turbo's compressor is so understressed that i doubt you will have issues running it up to something like 12-13 psi in the upper rpm range.

Most high-power setups get around the need for 2stg boost control by running such a large turbine that they dont make peak boost until well past the engine's 'natural' torque peak anyway, but you are running a very small turbine for the displacement (t3 based but you didnt say exactly what?) so you will have to intentionally limit the boost at peak torque rpm and raise it later to get the most peak hp without blowing up at 3600 rpm. Having said that, i think there is probably something you can change to get WAY more than 230rwtq peak at 3600 rpm. It's possible your ONLY issue at present is spark blowout. The plug gap change will tell.

bakes
11-16-2014, 02:54 PM
Nice build if mine i would find a 92 up 4.ol jeep fuel rail and injectors and throttle body might be able to swap distributor and tone wheel for the front of the crank then get a Megasquit3 that should unlease the beast

Serj22
11-29-2014, 01:24 PM
Sorry I couldn't log on to Turbo-mopar for a while. Was the site down or something?

Anyway. I changed the gap down as suggested and it seemed to help a little. I closed them to .023 and tried it. They were originally gapped at .028 Which I'd think would have been fine - but at both gaps the engine still has a noticable weird sound like frying bacon at about 3700rpm which might be why the operator was shutting down at that speed. You can hear it without a det can or mic.

Currently it has a MBC that allows it to hit 8psi and that's where I have it set.

I think I may need to control pre-ignition better here is the problem. I'm running premium. I also have the governor limited to only allow 8* advance. The vacuum advance I believe is not pulling off quick enough during boost. I have a volvo vac pod off of a 240t from the 80s that should actually retard under boost. I just need to adapt it to the arm on the dizzy now.

The issue now though is i don't see how 18 advanced is too far to preignite.

Could the temperature of the plugs also effect this? The ones i have are one step colder than a stock plug, but there are "colder" ones available.

I'm looking to see how high it can get off the stock reciprocating assembly and cam. Others are "supposedly' making more power, but no dyno backup on any of that. Just - "Turbo stock slant 10psi= 250hp"

It could be true and I just have my tune nowhere near complete. Fuel delivery is not an issue, and it is not running lean. The issue here seems to be electronic. The other control I have is a MSD6ALN I can add, and then later add boost retarding unit, but I haven't rigged that up yet.

BadAssPerformance
11-30-2014, 11:41 AM
Nice project car! 4-door sleeper too!

One of the Chicagoland Mopar Club guys, Dennis (Slantzilla maybe?) just runs nitrous on his and says everyone using a turbo has issues. I'd love for yours to prove him wrong! :)

A couple thoughts...

Mmmm Bacon! Can you get a video of this? Detonation sounds like a ping noise. A frying sound would make me think something else?

At 3700 you power is dropping off on the dyno, is it possible its possible that its running out of fuel or getting choked on air (intake or exhaust side) somewhere so the opposite, too much fuel?

What do the plugs look like?

To diagnose if you think its breaking up due to pre-ignition/detonation, throw in some 100 octane or at least some octane booster to see if it changes anything.

To diagnose if timing is too much, reduce your base timing and see if it changes anything.

To manually control timing retard with boost, MSD makes a couple different models of BTM's (Boost Timing Master) that are adjustable from like 1° to 3° retard per pound of boost. At least a couple of the ones they have should work with your 6AL box.

Ondonti
12-01-2014, 07:38 AM
Stock timing, race gas, and about 4psi boost would walk all over what you have going on right now.

If JT says that all Slant 6 turbos run poorly and you say that everyone with a turbo slant 6 says "You must never run more than 18 degrees advance in ANY boost" I think we have a correlation going here.

Timing requirements are dynamic. Simply switching from regular octane to premium should get you the first 4 psi boost on stock timing. Then timing should bump down as boost rises once you near the boost limit allowed by the increased octane fuel. The rest of the timing map (I know there is no map) should nearly mirror the non boosted timing numbers @ WOT.

Has your system been pressure tested? Carb likes boost?

spyder
12-01-2014, 08:37 PM
One of the Chicagoland Mopar Club guys, Dennis (Slantzilla maybe?) just runs nitrous on his and says everyone using a turbo has issues. I'd love for yours to prove him wrong! :)



Wait, what?? Everyone??

Check your trusty Turbo-Mopar data base ;) These aren't too shabby...

66 Valiant Signet225ci /6 Turbo IntercooledA727 (2.94:1)26x8.5x14 MT SlicksRyan Peterson (turbo66valiant) http://www.turbo-mopartimes.com/flags/us.jpg1.57 6.86@100.48 10.74@127.47

70 Dart Swinger3.7L /6 Turbo FMIC AlkyA904 (2.76:1)255/60/15 MT ET StreetsTom Wolfe (shaker223) http://www.turbo-mopartimes.com/flags/us.jpg1.572 7.06@97.50 11.02@120.56

spyder
12-01-2014, 08:56 PM
BTW, if you find your problem is not fuel/ignition related, check the valves springs. IIRC they're awful weak on a /6, maybe only 50lbs on the seat, doesn't take much boost to float 'em...

Vigo
12-01-2014, 10:07 PM
^Excellent point, the pressure in the exhaust ports could be causing the exhaust valves to float under full boost.

Serj22
12-04-2014, 09:57 PM
I hadn't even thought of the valves floating like that. I believe the valves are stock replacement. When I had the head rebuilt the machinest put in new valve springs, new valves and seats, and cleaned the whole thing out, along with 12 new push rods and 12 new lifters. Not sure if the springs being new would help their strength unless they're still just rated for 50. The intake and exhaust are stock specs. I set both while the car was warmed up and idling.

.010 intake, .020 exhaust.

Ondonti, I am not sure what you mean by pressure testing the system? It's been running on my slant for a while. I'm close to 3k miles on this setup and the motor seems happy enough with it. I wouldn't say it runs poorly, as it is a lot quicker than a stock slant 6 and gets nearly the same mileage. The carb is running off larger jets as opposed to having a functioning power valve, but it never goes lean under boost - always right around 11.8. -Sometimes 10. The next step I would do with it is I'll be making a BRPV for it, and utilizing a tube from the J-pipe to the power valve cavity to activate it. I've heard the pressure in the exhaust before the turbine is more than the intake side. Right now it's just a thought, and I haven't begun to actually change it because the car always seems to get adequate fuel. The carb itself seems to be doing fine. I get my pressure reading from the manifold so I know that the reading on my gauge is what is actually getting past the carb.

Also this car isn't really going to run race gas. It runs Premium right now. I opened the governor on the distributor a little more and it made the frying bacon sound throughout the 4-8psi range.

Right now I'm working on a bastardized electronic ignition distributor that has the Volvo 240T advance/retard pod on it. It should allow me to run a stock timing setup, and cause it to retard under boost. We'll see how it works out.

Also as of today BasAssPerformance, I set the initial back slightly but left my more opened governor position which seems to allow about 12* of advance, over the 8* it did before and see what will happen tomorrow when i get a good chance to drive it around.

Edit: ALSO - I just realized, at exactly 35 seconds in to the video I posted up top of my Dyno pull, you can actually hear the frying sound I'm talking about.

Ondonti
12-05-2014, 07:31 AM
I mean pressure test between the inlet of the turbo and your engine. I want to know how your carb is dealing with boost and if you have leaks. I mentioned race gas only because I question the tune. Lots of people run race gas instead of getting the tune right. The simple bump to premium should allow you to run bone stock timing plus 4-6psi boost.

New springs will be much stiffer than old ones. I would bet that when new they measure higher than required because its known they will relax over time. Other springs are like that.

How did your ignition timing at 10psi compare with what timing should have been at WOT on an n/a slant 6 ? And what should it have been at varius rpms, like 2500, 3000, 4000, etc. Then what was it actually? Guessing your are running premium and stock timing calls for 85-87.

Would you open up your wastegate and see how the car behaves with no boost? I would be interested to know your intake temperatures too. I think you jumped too far ahead in the boost game for a first attempt.

Serj22
12-05-2014, 08:26 PM
I initially had the turbo mounted with a huge exhaust leak that ran at 0psi, and the turbine barely spooled. Basically my old wastegate leaked like no ones business and no heat or pressure seemed to reach the turbo - just enough to spin it. Running without boost in that setup, I still managed the same AFR's so I know the fuel pressure reg is spot on (I think) since it's the same under boost at WOT, and cruise.

On my stock setup, i was running a 2 barrel Weber 38/38 and had it dialed in perfect for the slant. No afr gauge at that time so i was just reading the plugs on a regular basis. The initial timing I used on that setup was 12 degrees advanced. With the vacuum advance hooked up and revved to around 3000 it hit 32 and that's as far as it would go in the spectrum. AS far as slantsix.org is concerned, 32 should be spot on for maximum advance with a slant, and it operated well. I gave the pressure test a shot, using what I could find online which was have someone rev in drive and then shoot soapy water at the intake piping and such. I did that and there seems to be a slight bit of bubbling on the bottom of the carb, closest to the valve cover, and in one of the pipe silicone sleeves close to the carb hat. It's very small, and I'm guessing that's an issue... I did roll the ends of the pipes with a homemade beader so the hoses would stay on. Maybe they're cheaply made or something - I got the couplers from ebay and they all say "JDM" on them... wiped that off.

The carb base I suspected would eventually have an issue. I had to mount it with allen bolts with a tapered head in an adapter specifically for the 2300 Holley. I'll disassemble and see what i can do to ensure those don't loosen up again.

As far as the timing goes, retarding the initial a bit seemed to be very nicely met by the car - and it is super quick, but now is a dog after 70mph. I might get this other distributor finished soon and hook it up. It has the stock timing curve and a pod from a Volvo, that will allow it to retard if need be. I can leave that disconnected for initial testing though.

BadAssPerformance
12-05-2014, 08:53 PM
Wait, what?? Everyone??

Check your trusty Turbo-Mopar data base ;) These aren't too shabby...

Oh, I know there are quick ones out there, have even seen them, just not many


Also as of today BasAssPerformance, I set the initial back slightly but left my more opened governor position which seems to allow about 12* of advance, over the 8* it did before and see what will happen tomorrow when i get a good chance to drive it around.

Edit: ALSO - I just realized, at exactly 35 seconds in to the video I posted up top of my Dyno pull, you can actually hear the frying sound I'm talking about.

12° total timing should be enough at high RPM... down low you'll want more though

I watched it 3 times and unless I'm missing something by seeing video instead of live in person, the "frying" noise sounds like air pressure so maybe from the exhaust or from the carb?

What size exhaust is it? For /6 I would think at a minimum 3"MB pipe to not choke it?

Ondonti
12-06-2014, 07:42 AM
I initially had the turbo mounted with a huge exhaust leak that ran at 0psi, and the turbine barely spooled. Basically my old wastegate leaked like no ones business and no heat or pressure seemed to reach the turbo - just enough to spin it. Running without boost in that setup, I still managed the same AFR's so I know the fuel pressure reg is spot on (I think) since it's the same under boost at WOT, and cruise.

On my stock setup, i was running a 2 barrel Weber 38/38 and had it dialed in perfect for the slant. No afr gauge at that time so i was just reading the plugs on a regular basis. The initial timing I used on that setup was 12 degrees advanced. With the vacuum advance hooked up and revved to around 3000 it hit 32 and that's as far as it would go in the spectrum. AS far as slantsix.org is concerned, 32 should be spot on for maximum advance with a slant, and it operated well. I gave the pressure test a shot, using what I could find online which was have someone rev in drive and then shoot soapy water at the intake piping and such. I did that and there seems to be a slight bit of bubbling on the bottom of the carb, closest to the valve cover, and in one of the pipe silicone sleeves close to the carb hat. It's very small, and I'm guessing that's an issue... I did roll the ends of the pipes with a homemade beader so the hoses would stay on. Maybe they're cheaply made or something - I got the couplers from ebay and they all say "JDM" on them... wiped that off.

The carb base I suspected would eventually have an issue. I had to mount it with allen bolts with a tapered head in an adapter specifically for the 2300 Holley. I'll disassemble and see what i can do to ensure those don't loosen up again.

As far as the timing goes, retarding the initial a bit seemed to be very nicely met by the car - and it is super quick, but now is a dog after 70mph. I might get this other distributor finished soon and hook it up. It has the stock timing curve and a pod from a Volvo, that will allow it to retard if need be. I can leave that disconnected for initial testing though.


Thats not really an answer about the timing. What is the stock WOT "zero" psi timing number at various RPMS. 2500, 3000, 4000. Then how do your current numbers compare. 12 degrees of total timing might work on a 4 valve head 2.4L at high boost but its not what a low boost engine needs. Nobody with a TD runs "low boost" and low timing...For TDers, low boost is more than you are running.

If your OEM motor had 20 degrees of timing at WOT at 3000 degrees, then with premium grade fuel, you should get a couple psi boost without changing timing at all. then back off 1 to 1.5 degrees or so (very safe) for each psi of boost beyond 4-6 and you should be pretty close. 10psi should not radically change your spark requirements. There are probably guys out there running double or triple the boost as you and they have extremely different spark advance needs.

Timing should increase eventually after peak torque which is what those govenors or whatever you welded would accomplish. Rereading, I think you should run 2 steps colder on the plugs when doing all this and gap them @ .022ish.

"vacuum advance is not pulling off quick enough during boost" this would mean that its really not working at all then....or something greater than atmospheric pressure is fine.
Interested to see how it runs with the volvo setup. I think I would rather run 100% stock and then have boost retard, however you accomplish that, MSD or the Volvo parts.

Vigo
12-07-2014, 01:11 PM
Vacuum advance should move basically faster than you could follow with the naked eye if you just flashed boost to it so if it's not moving quick enough it's broken.

12 degrees total timing is NOT enough for an old---- combustion chamber at low boost. Timing requirements are a reflection of how much time it takes for combustion to finish and a newer 4-valve cyl head with the spark plug very near the center of the combustion space is going to take a lot less time than a slant6. I think it should have MORE than the 18 he has now if everything was working properly.

So in my opinion the question is not 'does it need more timing' because i think the answer is yes, the question is what is keeping it from working better as it sits? I think exhaust valves floating from backpressure at peak boost is a prime suspect although i wouldnt rule out that other things are also having a small effect such as minor air leaks or the fact that it ran a little different with less plug gap. I just dont think those are the main issue.

cordes
12-07-2014, 02:09 PM
I too would think that there must be a mechanical element at play to not allow for higher than 3.7K RPM.

I would echo what JT said about the exhaust being large enough too. 200+cu.in. is way larger than our 153cu.in motors which most all of us run a 3" exhaust on and notice gains. A lot would be left on the table with anything smaller in a larger motor IMO.

Shadowv4l
12-07-2014, 11:44 PM
Time to drill the intake manifold and add injectors? That's what I always thought the turbo slant 6 guys did.

Serj22
12-08-2014, 12:06 AM
I think I have a theory as to what can be the issue here - I recently changed the "boost" gauge to a "boost/vacuum" style and notice i only get 10 inches of vacuum under idle. I tried adjusting the bleeds, and it's still 10. From what I can see this usually means a small vacuum leak, or valve timing is off. I'm thinking the latter as i have recently rebuilt the carb now, and made dead sure there were no leaks during reassembly. I also rejetted and built a BRPV, and boost referenced the BRPV cavity.

I looked up some info on slantsix.org and it seems timing chains slacking out is a common issue, and I'd think at 47 years old (even with only 100k miles on it) I may have a slacked chain and have the wrong timing all-together. Oreilly's had a new entire set (chain/sprocket/ gear) for $25. I'm thinking it's worthwhile to replace anyway and then see if the degree is still right on the cam. It could be slightly off.

Right now i have 2 1/4" exhaust leaving the engine manifold, and leaving the turbo it turns into 2 1/2.

Needing more timing is a big possibility, I'm just looking at it like Vigo says where I'm wondering why it doesn't work better as-is. My whole setup is almost a blatant copy of about 4 other builds that work really really well with worse quality parts in some cases. The timing and everything else is identical to those, so why not as good? This is another reason why I'm considering no matter how i set the timing on the distributor I believe it's off in general, or walking around so to speak.

I gave it a good go in 1st gear and i can get it to rev over 4k RPM just fine, it just doesn't seem to make any more power there. I don't disagree that there should be more timing in general, I'm just concerned as to why if everyone else runs 18 total, why mine doesn't seem to run right with just 18. It could be that I'm running low boost in which case like Ondonti says I can get away with more timing (which makes sense) most of the builds i see people are pushing about 14psi - which seems to be the general number. SOme are 20, but most are 14.

I'm also guessing based on this info that the vacuum advance is pulling off just fine. One other thing is just a couple days ago, I was driving the car on the freeway, but really "driving it" if you know what I mean. I stayed in boost longer than I ever had a need to before, and after about 30 seconds at high RPM and 8psi, the AFR went from 11.8 to 16 very slowly, so I let off, and drove under vacuum home. This prompted me to rejet and build the BRPV, because obviously the regular power valve wasn't working under boost conditions and the jets obviously couldn't keep up over time. I believe having the power valve function on boost now, should help add fuel if the car stays in boost. The fuel pump is more than capable of keeping up, and the regulator is working just fine - it increases 1:1 as it should. And sorry Ondonti I don't really have a good map of how the timing goes throughout the RPM range. I am doing all of this in my driveway at an appartment, and do not really have an extensive tool set for checking things. I have an 80s snap-on timing light that can count backwards to guess timing, but the mark as far as everyone on slantsix.org is concerned "doesn't always mean 0" and with a sloppy chain, it will walk - which it seems to be doing. I didn't really get a good baseline either of how it ran under n/a operation because it ran good and got decent mileage, so I left it alone - there was really no reason to check after that for me.

- - - Updated - - -


Time to drill the intake manifold and add injectors? That's what I always thought the turbo slant 6 guys did.

Some do - yes, but I don't have the knowledge really to build an electronic injection system. I read up for about a year on turbo stuff before I thought i could accomplish the turbo setup, and went for it. I am thinking of pursuing EFI, with a COP design for spark, but that is in the future when I can afford it. Right now the car drives me to work every day so huge downtime is not in the books. Once I can put it to the side as a purely fun car I'll probably do that, then bring it back as my daily driver anyway. It's just hard to go buy parts for something if you have the car taken apart and undriveable.

Ondonti
12-08-2014, 03:14 PM
I think your setup looks a little too pretty to have some of these worn out parts :P Would also be nice if you could pressurize your exhaust and see how the valves behave

While I did not directly say it, I am questioning what the timing is stock, what you are trying to time things at, and MAYBE what is really happening with the timing.

I have run my Junkyard with 10 degrees pulled across the map and it lost a lot of power but still seemed to run fine. I ran my Spirit with base timing accidentally set below zero and it was terrible :X

Your exhaust is small but its not killing power as drastically as you are suffering. Yes it would be a good mod to go 3" but 3" can handle 750hp (triple your goal) and at that point it definitely hurts.

I have never done it but if you were on the dyno again, I would take a timing light. I would assume that you can mimic full WOT conditions in neutral, I won't try to remember too well how your carb and timing works as you keep changing it. I have struggled in the past with commanded timing vs actual timing. My megasquirt did not lie to me but because of how I set things up I couldn't actually achieve certain timing numbers that I commanded. It would be pretty cool to see this car running Megasquirt but I know that takes out a lot of the slant 6 fun. Ghetto tuning is pretty frustrating. You probably don't know but I spent a lot of time with ghetto added fueling and a stock N/A ECU for timing. Ive run 24 pounds of boost on a stock motor with stock n/a timing on E70+Methanol as well as 26 pounds of boost on a built shortblock, 8 degrees more timing than n/a stock, 91 octane + Methanol. At least with a carb'd chevy or ford etc, you have more control over the timing options. Lack of timing control is why I gave up pushing the envelope. I always hit a brick wall where I didn't want to put anymore octane or methanol into the motor to keep upping power.

I also don't compare boost numbers straight across. 10psi on a bad tune from a huge turbo is worse than 10psi on a bad tune on a small turbo. That is simply because your power level will be higher...unless the turbo is so much bigger that your torque numbers at peak suffer (which is a good thing for the motor surviving).

Serj22
12-08-2014, 11:38 PM
Well, with an absolutely "stock" slant 6 the timing should be 0 initial while idling, and 32 advanced at "All in" with no vac advance hooked up with a 1 barrel Holley Carburetor. On that setup I went to 6 advanced just because it ran better.

When you move to the two barrel, like i did - it varies, but the Weber liked 12 degrees initial at idle and 32 all in with the vacuum advance off and that worked great.

This two barrel 350 is a little smaller than the Weber in CFM, but more adept to tuning and has more information out there for blowing through modifications. The timing currently is 8 degrees advance initial, and 18 "All in" with vac advance disconnected, with the vac advance connected it gets a lot higher on vacuum, but under boost - it is 18. I have not been able to get a good number with the vac advance as I'd have to place the car under load to see the transistion and it's hard to hold a timing light on a car that starts a 1 tire fire when you brake stall it. Like you said, it'd be good to bring one to a dyno and check. I'm sure they wouldn't mind.

One thing I have made a breakthrough with is fuel delivery - having changed the power valve to operate on boost rather than vacuum, I get a much more steady fuel reading when transferring into boost - I still need to increase the jets I think, as there is a big noticable gap from where the jets can maintaint - to the power valve turning on. Just as I'd be able to hook up the electronic distributor I have in a couple days - there is going to be a good rainstorm so that's out till at least the weekend unfortunately. That distributor has the stock timing curve still there, and the volvo unit. It has one port for vacuum, and one for boost (push/pull) So I don't necessarily have to start out with a boost reference to it - and it will still function. We'll see what happens then I guess.

bakes
12-09-2014, 12:25 AM
i think 350 cfm even under boost is too small of a carb look to a 5oocfm 2bl holley of better a 4bl under 600 cfm as for the stock timing chain i bet it"s got over a 1" of slop if original and the cam would be close to round too

Ondonti
12-09-2014, 07:40 AM
i think 350 cfm even under boost is too small of a carb look to a 5oocfm 2bl holley of better a 4bl under 600 cfm as for the stock timing chain i bet it"s got over a 1" of slop if original and the cam would be close to round too

Cam wear, interesting point!

What octane fuel were you running 32 all in with? If it was 87 and then you went to 92 octane, you should be able to run a few psi of boost on 32 "all in." If you were on the ragged edge when running 32 then you might only want to run the first 2 psi boost on full timing. If you already were on 92 octane without turbo, timing has to start dropping right away. I think I usually had lazy timing at 0 psi boost so that timing would move into the efficient yet safe zone as boost came on. Thats what happens when you have no boost retard. The new distributor sounds kinda interesting. What does it actually do to retard timing and how much change can it make?
If the combustion chamber is really detonation prone then that would force you to have to pull more timing with boost. I would hope to get away with 1 degree per psi or less. For comparison sake, the SRT-4 maps pull between .5 and 1 degree per psi of boost depending on the boost level.

I would think that a 350cfm carb will move a lot more air under boost just like n/a throttlebodies can be very small on turbo cars but need to be massive on n/a cars.

Force Fed Mopar
12-09-2014, 11:12 AM
I would just bump the timing 2 degrees and see how it does :)

Serj22
12-09-2014, 11:14 PM
I too believe 350 is plenty, because if you look at it mathematically, it only takes 325 cfm to turn a 225 cubic inch motor @ 5,000 RPM if the volumetric efficiency "were" 80%. 500 is just adding another power valve and jets that i have to play with - while it does add another "stage" that would be nice, I'd like to dial in this carb first. Once I get the timing chain and oil pump off, I'll take a look at the cam if I can. Hopefully it is not rounded like Bakes is saying.

Maybe I am misinterpreting it - the car does not run bad - and is very nice - but I feel it should make more power under the current setup based on other stock builds which also use 350 carbs.

Ondonti I was running 87 stock after I got hardened valve seats installed so that it would be possible - before that I ran premium just to prolong the life of those - which ultimately failed 6 months into owning the car and dropped two exhaust valves (the car still ran on 4 but really slow) - to prompt an entire head rebuild. That was probably the best deal around - $270 got the whole thing redone - new valves, seats, springs, hot tanked, painted, resurfaced, new push rods - etc.

As for the new distributor - on the top plate, on a normal distributor - it pulls and moves the plate over and advances, then gets let go to the 0 position. On this one, the groove was enlarged by the previous owner, so the plate can move forward and back and uses a combination of the volvo plate and arm so the pow connects. This move with the 240t distributor has been talked about on occasion with slant6s but I've not seen one used yet. The plate moves in either direction with a connecting rod to the diaphragm. On a stock mopar one, it only pulls with the vacuum. The swap itself is done a lot of times on Volkswagons and some other Turbo cars - not a whole lot of experimentation with slant 6's though. AS far as i know the original owner never actually used it - he just had plans to. I finished assembling it as it was still a bunch of parts when I got it and am thinking it could work nicely.

This is the 1982 240t Volvo Unit in Entirety:

http://i.ebayimg.com/00/s/MTIwMFgxNjAw/z/BFgAAOxyBC1R9~-Z/$T2eC16RHJHEFFmVZu(-lBR9+-ZFC!g~~60_35.JPG




And the Mopar Stock Electronic Ignition 6 cylinder Distributor:

http://www.forabodiesonly.com/mopar/attachment.php?attachmentid=1714632163&stc=1&d=1372212048

And this is my distributor:
http://i43.photobucket.com/albums/e356/serj22/Turbo%20225/IMG_20140829_091510_zps55843fd2.jpg

http://i43.photobucket.com/albums/e356/serj22/Turbo%20225/IMG_20140829_091520_zpsc531f13d.jpg

http://i43.photobucket.com/albums/e356/serj22/Turbo%20225/IMG_20140829_091500_zps68ba5fca.jpg

http://i43.photobucket.com/albums/e356/serj22/Turbo%20225/IMG_20140920_211143_zps69eadbf8.jpg

I feel like it is ready to use, but I don't have any information on how far the timing will back off under boost or how it reacts to anything - and would only be able to tell if I installed it on a Dyno.

ForcefedMopar - I am not against doing that. I can do that till it pings and see where it gets me.

But Ondonti - I like what you're saying about setting timing to come in in stages. What would i have to do to work that out? I have a MSD 6aln ready to go - but what would need to be run off of it? I feel if I did it that way, I could just divert the current distributor to its normal governing plate and curve, and then retard it electronically with that. I'm assuming there's possibly an MSD compatible unit for it? ANd if so how/ and how well does it work?

Vigo
12-10-2014, 09:48 PM
but I feel it should make more power under the current setup based on other stock builds which also use 350 carbs.

I think you're right about that. Even if the thing didn't make a lot of horsepower, i would think a low-rpm-biased 225ci engine with 8 psi should be making well over 300lb ft of torque, even over 350.

bakes
12-10-2014, 10:11 PM
Hmmm still think 350 cfm is to small as per carbs from back then from personal experience they really didn't flow what they were rated at when put on flow bench bet if would be closer to 275 cfm