15.71 @ 107mph What a weird timeslip!

[powermaxx]

Some background here:
Recently swapped an A413 into the GLHS with a so called Hi Stall converter (I think the altitude is the problem). Can't get it above 2200rpm so no boost and it takes forever to get it to where it starts spooling.

At the track;

Knew I had to go to keep points (was sitting in third place) even if the car was running like crap. So I line up and stalled as best I could and launch. Did I say launch? You could of out run me on foot! 2.95 60'er's!:bolt: At about the 330 it starts coming on. Tires break loose at the top of second gear (real street tires vs my normal drag slicks). It's sorta fun in a sick way. Well I couldn't do a consistant "Roll on the Throttle" (bogging/stalling, etc..) so it was hard to pick an ET. Went out in round two against the points leader. :banghead:

It ran like some of the throttle stop cars (launch, looks like a bog and then it goes like a bat of hell). It made a few normal racers freak out and they couldn't stop talking about it. It was fun but I'd rather have my normal 1.85 60' and 12.3's passes. New 4500 stall convertor from Pat's is on its way and that should put back on track.

Only two races left so this better happen quick if I'm going to salvage any of my seasons points.

[GLHNSLHT2]

ouch.

[GLHSKEN]

Sounds like you need a 50 shot to get off the line

[tryingbe]

You need to get your $$$ back for the "high stall" converter.

[BadAssPerformance]

*cough* 5-speed *cough* :thumb:

[turbovanman²]

I would find a stock cal and just run that for now or see if Shelgame or Cindy can whip you up a new cal for your new combo.

[glhs875]

The right converter will make a huge differerence and will all but eliminate turbo lag. I have a Pat's converter in my car and I love it. And he will fine tune the converter to your liking if you want. You need a really loose converter up to 4000 rpm and then will get tight/more efficient after that point. In the upper R's (6500rpm +) my converter only has about 12% slippage. And it will easily stall high enough to build boost with a SC6152 turbo on the line. In fact once boost is made my converter flashes and will stall as high as 5500rpm, and once the hammer is dropped, all hell breaks loose!!! And I don't think even slicks will hook up that much power!. The air fuel ratio at the break torque area and also the launch area (no and low boost area) is very critical to good response. Too rich or lean in this area can make or break a combo and make it WAY more laggy than it normally would be. The perfect converter would be one that stalls to the torque peak area of the engine and then tightens up after that point. And then work on the tune in off and low boost to get better response. Works for me!!

[20w/ashelby]

*cough* 5-speed *cough* :thumb:

:thumb: agreed

[powermaxx]

:thumb: agreed
5spd's are fun, don't get me wrong. But this is a bracket race car and in my class if you don't have .05 package or better......

YOU LOSE!


I have a wall of trophies (the ones I kept :D ) and several track championships. I want more and to make a statement about our FWD cars to the RWD guys. I want the same reuptation I had with my Challenger where people would pull out of line so they didn't have to race me.:evil: (Typical Challenger package was .015, it was killer...)

If I want to go really fast my Challenger is almost updated with the new blown HEMI and 180mph should do just fine for my "Speed Fix". :thumb:

[powermaxx]

The right converter will make a huge differerence and will all but eliminate turbo lag. I have a Pat's converter in my car and I love it.

Quick update (well long at least...:D ). Installed a new converter (Pat's). with a "Sea level" stall of 5000rpm.
That may seem high but altitude affects HP even on a turbo (Steve Beher(SP?) even confirmed that, as he has a few Buick GN's running up here.

So thrash after work and get it in late friday night. So Sat morning I test it in the driveway. Only goes to about 3100rpm :( . It's a lot better but still long way off (I haven't talked to Steve B. about it yet). So I got to thinking about what's what and was looking over my dyno curve some more. So I figure the power band just isn't low enough for the turbo to start kicking in and it must be seeing basically a NA type power curve at 3000rpm's.
I run a G head just to make the lower end a little "Soft" to aid in traction (L Body...) and to run pump gas at 28psi. So I figure I've killed off to much power for a normal power curve (I've run many a pass in the Challenger and know what a high stall feels and acts like...). So I figure I'll bring the power curve down by advancing the camshaft to 10 degrees.

Wow!:nod: It makes power now and holy smokes! (Literally!) So I adjusted some more and came up with 6 degs advance but these turbo cars and converter stall are really weird (at least mine is...). Mine stalls initially at 3100rpm and then it slowly makes it way up to about 3400-3500 and the turbo starts spoolling and then it really starts to climb! It gets to about 3900 rpm and my brakes can't hold the car (foot brake racer, no tranny brake) so I really don't know where the stall actually goes to (yet).

So here's my theory and would like to know if this is normal for a low 12sec car with a g head.

G head is lazy in the bottom end compared to a swirl. So it already makes less power (before turbo kicks in) than a swirl.

As I power brake it the convertor stalls at 3100, as the power getting into it is low. It slowly builds (not sure if it's converter slippage or boost starting to build, nothing on the boost gauge) to the point where it makes boost/power at 3500rpm. Turbo kicks in and with the new power level moves the rpm/stall very quick (and I mean QUICK!!!). This all takes about 2 to 3 seconds (from 3100 rpm to where the tires break loose) which will be very hard to control for a consistent launch.

Until I get new brakes (SLH mod or better...) I figure I'll set the rev limiter for about 3750rpm's and just time my staging accordingly. 2 to 3 seconds! Sheesh!!!



So moving the power band down verified I'm not making as much on the bottom end as I thought. My dyno curve has a very sharp climb up when 3500 rpms is reached. It almost looks like nitrous coming on! So it looks like I have to live with the weird stall and compenstate with the launch routine (come up on the converter and power brake it into the staging beams). Is that how you guys do it? (I'm looking for other TM cars running low 12's and a G head combo to answer this please. But I'll listen to everyone....:) )

Sorry so long folks! All of this testing is for my "Special Purpose" project and I'm trying to learn the ATX stuff.

[Ondonti]

just wanted to mention that nowadays lots of people using auto trannies in FAST cars are looking towards running tight converters and spraying 20-75hp worth of nitrous (depending on if its FWD RWD or AWD) to spool the turbo.
That small amount of nitrous wouldnt cause crazy traction issues but is would get you into your powerband sooner.
Lots of people will turn the spray off after the turbo has achieved about 2/3 of peak boost.

On spray with a tight converter you can run faster then someone with a loose converter that is gobbling up power.

[powermaxx]

just wanted to mention that nowadays lots of people using auto trannies in FAST cars are looking towards running tight converters and spraying 20-75hp worth of nitrous (depending on if its FWD RWD or AWD) to spool the turbo.
That small amount of nitrous wouldnt cause crazy traction issues but is would get you into your powerband sooner.
Lots of people will turn the spray off after the turbo has achieved about 2/3 of peak boost.

On spray with a tight converter you can run faster then someone with a loose converter that is gobbling up power.

Thought about that also. I used to run nitrous in the Challenger and got tired of the game of; How many passes, too high/low of bottle pressure, did I turn it on.... But that was on a 500hp system (2 passes per bottle...).

Now 50hp shot off the line and then turn it off may be a lot different but I'm trying to avoid that as it means a weight penalty in one of the classes I'll be running. (But I will be keeping it reserve if I have to!):thumb:

[glhs875]

I have a Pat's converter in my car. I stall mine to about 3200rpm on the line. Get's kinda tight there off boost. When boost hits, the converter flashes to 5000 to 6000rpm depending on how much boost I'm running and never drops below that point, but gets really tight above that point. Works great for my type of tuning/setup. One thing you can do to make more boost easier on the line is to have a bunch of timing retard in the launch rpm area only. I'm talking like 15 or more degrees. That will also kill some power and make it easier to hold the car against the brakes. You just need to make sure the timing goes back to normal right after the launch. The retarded timing can allow a manual trans car to make boost just by free revving. And should work even better with an auto trans.

[Speedeuphoria]

One thing you can do to make more boost easier on the line is to have a bunch of timing retard in the launch rpm area only. I'm talking like 15 or more degrees. That will also kill some power and make it easier to hold the car against the brakes. You just need to make sure the timing goes back to normal right after the launch. The retarded timing can allow a manual trans car to make boost just by free revving. And should work even better with an auto trans.

Any info on what the EGT's look like while retarding on the line?

[glhs875]

Any info on what the EGT's look like while retarding on the line?


They definitely climb higher! At least in the manifold/ header and turbine housing and probably would show up cooler in the cylinder. But, it's only for a few seconds or maybe less at a low power level, so engine/turbo, etc. damage is very unlikely. The best setup in my opinion, would be a button activated rpm limiter/timing retard so as to have both on/off. I will have such a setup on my car eventually. For when I start running slicks. The street radial tires can't handle it!!!

[8valves]

Any info on what the EGT's look like while retarding on the line?


Very hot.

[glhs875]

Very hot.


I could be wrong, but I don't think EGT's will actually be much hotter than what is normally in the cylinder itself. It will definitely show up being hotter on an EGT guage with the probe mounted in the exhaust system somewhere do to the hot part of the flame front happening more in the exhaust mani/header than before, and with that and the turbine housing absorbing more of the heat than usual instead of mainly the pistons, block, head, coolant, etc. Rally cars use such a device. A Hondata computer has an anti - lag option on it as well. With the timing retarded alot on the H 23 I built for a customer, it would hit 10+ psi by 5500rpm, with just one stab of the throttle while just free revving ( in 1 second or so). It has a 50trim hybrid .63 AR stage 3 wheel for a turbo.

[bn880]

I don't know man, I run a stock 86 T1 converter with a G head and just 7.2:1 CR, I can boost probably upto 30psi stalled near 3200rpm (but I dont want to!). I just run a stage 1 wheel with .48AR housing. Who knows if that's the big difference. Anyway, I can break traction on just about anything if I break boost long enough.

You really have to double check your fuel mixture at low boost, maybe youre way rich? i had that issue before with a stock cal, and could only build boost at part throttle not full. (too much fuel)

that reminds me, I will be retarding the cam a bit. Currently it's ~3 degrees advanced (TAFT S2) + 2 degrees from gasket heights. i say ~3 because it's a square tooth wheel on the TAFT 2.


Quick update (well long at least...:D ). Installed a new converter (Pat's). with a "Sea level" stall of 5000rpm.
That may seem high but altitude affects HP even on a turbo (Steve Beher(SP?) even confirmed that, as he has a few Buick GN's running up here.

So thrash after work and get it in late friday night. So Sat morning I test it in the driveway. Only goes to about 3100rpm :( . It's a lot better but still long way off (I haven't talked to Steve B. about it yet). So I got to thinking about what's what and was looking over my dyno curve some more. So I figure the power band just isn't low enough for the turbo to start kicking in and it must be seeing basically a NA type power curve at 3000rpm's.
I run a G head just to make the lower end a little "Soft" to aid in traction (L Body...) and to run pump gas at 28psi. So I figure I've killed off to much power for a normal power curve (I've run many a pass in the Challenger and know what a high stall feels and acts like...). So I figure I'll bring the power curve down by advancing the camshaft to 10 degrees.

Wow!:nod: It makes power now and holy smokes! (Literally!) So I adjusted some more and came up with 6 degs advance but these turbo cars and converter stall are really weird (at least mine is...). Mine stalls initially at 3100rpm and then it slowly makes it way up to about 3400-3500 and the turbo starts spoolling and then it really starts to climb! It gets to about 3900 rpm and my brakes can't hold the car (foot brake racer, no tranny brake) so I really don't know where the stall actually goes to (yet).

So here's my theory and would like to know if this is normal for a low 12sec car with a g head.

G head is lazy in the bottom end compared to a swirl. So it already makes less power (before turbo kicks in) than a swirl.

As I power brake it the convertor stalls at 3100, as the power getting into it is low. It slowly builds (not sure if it's converter slippage or boost starting to build, nothing on the boost gauge) to the point where it makes boost/power at 3500rpm. Turbo kicks in and with the new power level moves the rpm/stall very quick (and I mean QUICK!!!). This all takes about 2 to 3 seconds (from 3100 rpm to where the tires break loose) which will be very hard to control for a consistent launch.

Until I get new brakes (SLH mod or better...) I figure I'll set the rev limiter for about 3750rpm's and just time my staging accordingly. 2 to 3 seconds! Sheesh!!!



So moving the power band down verified I'm not making as much on the bottom end as I thought. My dyno curve has a very sharp climb up when 3500 rpms is reached. It almost looks like nitrous coming on! So it looks like I have to live with the weird stall and compenstate with the launch routine (come up on the converter and power brake it into the staging beams). Is that how you guys do it? (I'm looking for other TM cars running low 12's and a G head combo to answer this please. But I'll listen to everyone....:) )

Sorry so long folks! All of this testing is for my "Special Purpose" project and I'm trying to learn the ATX stuff.

[8valves]

I could be wrong, but I don't think EGT's will actually be much hotter than what is normally in the cylinder itself. It will definitely show up being hotter on an EGT guage with the probe mounted in the exhaust system somewhere do to the hot part of the flame front happening more in the exhaust mani/header than before, and with that and the turbine housing absorbing more of the heat than usual instead of mainly the pistons, block, head, coolant, etc. Rally cars use such a device. A Hondata computer has an anti - lag option on it as well. With the timing retarded alot on the H 23 I built for a customer, it would hit 10+ psi by 5500rpm, with just one stab of the throttle while just free revving ( in 1 second or so). It has a 50trim hybrid .63 AR stage 3 wheel for a turbo.

Sure. But who has an EGT gauge in their combustion chamber! :p That's exactly why it will read hot.

We prefer AEM over Hondata... and when you use anti-lag on an AEM controller things can get very hot in that manifold/header, and make wonderful pop bang booms with some of the best fireworks you'll see!

As far as I know Hondata S300's only have a two step rev limiter, not an anti-lag. :confused:

[powermaxx]

Good comments folks! (Maybe this should be in a different area seeing as it's more technical vs Strip/Street :) )

Anyway, I just happen to have a couple of MSD 3 stage retard units so a test is in order.

Talked to Steve Bahr at Pat's and he confirmed my theory. So I will need to learn how to stage with no boost or keep the cam timing advanced. It is bracket racing so I can learn either way.

As far as fuel during staging it goes lean so I don't think I'm overly rich.

Don't mind learning now but next season I want to be a terror right off the trailer!:evil:

[glhs875]

Sure. But who has an EGT gauge in their combustion chamber! :p That's exactly why it will read hot.

We prefer AEM over Hondata... and when you use anti-lag on an AEM controller things can get very hot in that manifold/header, and make wonderful pop bang booms with some of the best fireworks you'll see!

As far as I know Hondata S300's only have a two step rev limiter, not an anti-lag. :confused:


I noticed an anti-lag option on the Hondata. Not sure what all it will do. I need a users manual for the Hondata so I can learn how to work some of the options on it, so I can help out my Honda friend. I told him when he, and the rest of the young crowd that I know gets smarter, they will be driving Turbo Dodges!! :thumb:

[Ondonti]

well with the spray and tight converter you can more then make up for the weight difference AND you can place the weight strategically.
its bracket racing anyways so I dont quite understand your issue.
If you hate spray then you hate spray.
a 20hp shot for 1500 rpms in 1st gear would last a whole season with 1 bottle lol.

[Aries_Turbo]

you could hold the BOV open a little when brake boosting with vacuum like carl (dbltrbl) on TD did. it helped him get real consistent launches on street tires.

Brian

[GLHNSLHT2]

If you're boosting how do you get vacuum?

[Aries_Turbo]

store it in a canister with a one way valve and use a solenoid to connect the vacuum to the BOV when needed.

Brian

[DblTrbl]

Ha ha. I converted the vacuum canister after a while. I now use it to supply vaccuum to the cruise control solonoid instead. The cruise control solonoid controls the throttle to an adjustable (closed loop) boost level on launch. I don't need to watch the tach or boost gauge that way.