Sundance 6g72 "3.0 turbo build thread"(N/A DYNO SHEET pics inside)

[Sundance 6g72]

Good thinking on the valve cover deal. I guess I can weld it to the flanges directly. Id love to make a bolt on setup but im not sure the best way to go about that other than thickening the bottom plate to maybe 3/8" and threading some holes. Cover the holes with a welded plate of aluminum that way the studs/bolts can be removed rather than permanently locktighted into place.

I dont really see the downfall in welding directly on the lower intake. If the fitment is off, it will be off whether I use bolts or not and ill have to cut another piece.

The biggest hangup is getting the TB flanges to be level. The Chrysler TB only has two bolts and the gasket/TB/plenum flange do not have a flat level surface to reference. I have the dimensions for the TB flange correct but the TB might be angled a degree or so. In a perfect world, the TB setup will be perfectly level so I can attach a rod between both TBs so they have identical throttle positions 100% of the time with only one throttle cable.

[Ondonti]

Brent (Ondonti) is the person who welded steel and aluminum together...kind of. He still had to cover it with epoxy.

I can't remember if this has ever been brought up, but I'll throw this out there: We all know how very large throttle bodies screw with part throttle engine response. Well, why don't we take a page from the "old days" and have a primary throttle body along with a secondary throttle body? Hmmm...sounds familiar....kind of like a 4bbl carb! I guess they kinda knew what they were doing after all.

Yeah, the only purpose of the weld was to create and interference fit on my steel runners to the cut off upper aluminum flange. I would have had a steel flange made but when I was getting materials it was summer and the shop stuff at school was basically closed (no student programers who have access to pay to do the work). I made a drawing and then gave up. I had gone with an interference fit that failed and ruined a race day so I added small welds above and below the aluminum flange so that would never happen again. I had already epoxied this joint and did it again after I fixed it. For me I would almost want a throttle that was less sensitive around 800-1500 rpms and then more sensitive as the ability of the engine to swallow air increased (as rpms rise). Probably only possible with complex drive by wire programming.

BTW I would stick with a bolt on upper regardless of how high you want things or material choice. Make a stainless upper flange, or aluminum, whatever. I found that I didn't like taking apart the upper manifold so I would just remove the entire manifold if I needed access to something. My setup made that easy and its easier to work on then an OEM manifold. On the other hand, taking it apart requires removing what holds my fuel injectors in place which always made me grumpy. I realized I really had no reason to take it apart since I didn't have a 90 degree elbow mitsu style upper or hidden fuel injectors like a Chrysler 6g72.

Its really really easy to progressive throttle cam your TB. I think I overdid it on the 58mm on the Spirit because it feels gutless at low throttle. It is really easy to play with low rpm throttle inputs for leaving in 1st gear etc. If I used the same ratio on a much larger TB it would probably be great. The Duster has one too on the 65mm and I will definitely go with a much larger TB, probably 5.0 Ford style since the modular engine has no giant TB options.

[c2xejk]

For those looking for larger throttle bodies, I would recommend looking at ones from Inifiniti cars. The ones I got from (from a Q45, I think) have a progressive linkage stock. The two 80mm TB's were easier to control than that prior 2 58mm TB's.

[Sundance 6g72]

I acquired one of these at no cost to me. The feed port(s) appear to have too small of an inlet. Looks to be 1/8th inch. I think the actual thread in those areas will support something bigger (1/4 - 3/8?). I think im going to fit the biggest feed nipples on that I can source locally and then fit identical fittings to the plenums. The idea is to have each plenum feed into the block.

I plan to use the block to support
- MAP reading
- BOV source
- Wastegate/boost controller source
- Fuel Pressure Regulator
- Boost Gauge
- empty / extra port

Brake booster will get its feed from the rear plenum (between the firewall and the plenum). This will help keep the hose hidden and out of the way.
Intake temp will be mounted on the same side as the brake booster in an effort to keep the wiring hidden and the sensor out of the way.

I can always lose the boost gauge or T it somewhere else. I now I ran it to the brakebooster in the duster because the booster its self had an open port. I have learned to ignore my boost gauge anyways, its more of a decorative thing than anything else.

The MAP reading getting air from both plenums is an effort to keep the reading accurate. There should be little to know variation in pressure between both plenums but you never know.



In the future I can add macro fittings (similar to the ones used on paintball equipment and other pneumatic machines found in shops). I know my BOV and Wastegate will accept them. Its not high on the priority list though.


Back to the plenums them selves. I am hoping to find a way to have them offset just right so that the throttle bodies line up evenly. I think with the Alternator removed and the dizzy clocked forward (which I still have no idea how knitemoves did that way back when) I will be able to accomplish this. Also, im still not sold on the fact that I need to have the uppers bolted into place. Material usage might be an issue. Adding thickness to the bottom plate wont raise the intake up any further but it will cut down on volume (which im not concerned with). From a maintenance standpoint, i dont see why I would ever need to remove the plenums from the lower intake. They will be out of the way of pretty much everything I can think of but maybe im just being lazy.

I guess I can increase bottom plate thickness to 3/8th and add holes for studs to be locktighted and then use nuts on the underside to secure it in place with a stock gasket. If this all does work out, my buddy might consider making some him self and selling them (but im not sure how far that will go with all the downsides to having a large dual plenum setup.

I still need to go tear the upper plenum off one of my motors to measure holes spacing and diameter. I have not been feeling well sense Thursday and I have a Great Lakes Series Paintball Tournament on Sunday that I need to be healthy for.


tl:dr - waiting for vac. block to get here so I can size the source ports and get the cad file specced for the correct diameter holes and I also need to get measurements for the lower intake to mate up with the plenums properly. All in due time.

[Reaper1]

Usually I agree with the "less joints, the better" thing, but in this case, I still think it's a good idea to be able to take the uppers off of the lower seperately.

[Sundance 6g72]

well I have decided to go with a removable design considering it will allow me to "radius" the inlets of the runners as ed suggested. I made the bottom plates 3/8" thick instead of 11gauge. This way I guess I dont have to use Aluminum if I cant source any.

I got that vacuum block today. Its nice and includes all the fittings and hardware. Should work well. Has 6 ports (Boost, FPR, WG, MAP, BOV,). Im not sure what else needs to be hooked up to a line but I think that is it. Break booster will have its own dedicated port near the firewall.

[Sundance 6g72]

Im putting the finishing touches into the single intake cad. Right now my hang up is which throttle body to go with. It must be a junkyard throttlebody that I can find locally because I dont feel like spending more money than I have to. My local yard gives me deals on school projects. Im thinking a Jeep 60mm but I know I can go bigger and I would like to if I could. I have provisions for a 3inch throttle opening (76mm) but I can make it smaller if needed. Cant imagine id be going bigger.

It looks like the volume will be a little over 6L (but no more than 6.25 L). It wil be built out of Aluminum and tig welded and be bolted to the lower intake. The total height is 3 inches from the lower intake's flange. My stock plenum with half inch spacers was 3inches roughly.


side note, is the site slow for anyone? I can only get on with my mobile network. My home network wont let me get to the site and neither will tapatalk.. not sure what the deal is. I switched to google DNS and cleared my caches.. nothing helps.


edit: Did my volume math wrong. It will be roughly 6.5L if you dont include the throttle body adapter that will position the throttle body slightly away from the plenum in order for the throttle lever to clear without smacking the plenum because it does not sit flush with the throttle body flange.

[Sundance 6g72]

I acquired a ford 68mm (rear is 65mm) throttle body for my intake. I could go bigger but I dont think its necessary for my power goals and motor size (and drivability wants)



Now that I have my TB of choice I can move forward. I have the CAD pretty much done, just double checking dimensions so I dont waste any material.

Depending on the amount of resources available, I may do my double intake design after the single intake and have both options. If I go NA for a period of time, I would not mind doing it with a big dual intake. Or I could sell it

[Ondonti]

Nice to have megasquirt when the TPS sensor changes. I know some people here say "it works" on stock electronics but they are not very close when you look at them on MS.

[Sundance 6g72]

I dont see why they would be the same. Different sensor and different stock ecu (SBEC vs ford whatever)

I didnt run the TPS for a while. I plan on running it once I do this swap simply because im making a new harness and I mine as well. I was fine with MAP fuel enrichment vs TPS enrichment during throttle changes. TPS is needed for other things that would be nice to have again (idle advance, WOT shifting, etc)

[Ondonti]

TPS is also useful for interpreting datalogs.

[Sundance 6g72]

Intake project is still a go. Waiting for available time to actually do it.


So I bought a 3000gt. Needs work but got it somewhat cheep. Its a 94 VR4 complete with AWD, 6spd, and single turbo. Has too many parts to list and I need to go through it with a fine tooth comb before it will be drivable. Mainly needs an exhaust and a tune. It has the MAFT translator pro with GM speed density. Id rather run megasquirt II with the GM3bar so I think I am going to do that. It has a fresh forged piston motor (king bearings, 4 bolt mains, forged crank shaft).


Turbo is a Magnum Performance T70. Cant find much info on them other than that they are not china (brazil). Some people seem to like them others not.. so ill see how it goes.

[Sundance 6g72]

If anyone knows how much I could sell that stupid MAFT pro system (and 3/3.5" gm maf) for that would be great to know. I think I can get $250-300 out of it. I need it too for new wheels and tires. Current ones are ratchet.

[Ondonti]

already putting wheels on the car he can't drive.... hah.

Since the car is a money pit I would get the basics fixed before going too far with anything fun. Get the car driving to you can confirm there are not other problems which you might rather spend your money on. That would probably help the value if you needed to sell it.
Guessing I would compare that turbo to the Masterpower T70. It will make the power you wanted but its like the Western Family brand of mac and cheese. My supra friend raced one pretty hard for awhile. I wonder what turbine wheel is inside. His had a GTQ wheel (larger then the O or P trim wheels) so it had higher efficiency but laggy for the power potential of the compressor.

[MC#4]

3si guys will buy up the maft pro for top dollar. Not sure what the going rate is anymore.

[Sundance 6g72]

Turns out I have the original maft translator and the pro. Not sure if either works but ill sell them anyways and refund if they dont work.

The current wheels are bad (possibly dangerous). One has a decent dent and i dont think the tire is sealing well (not sure, time will tell). If I can sell the wheels, maft translator, maft pro, GM MAF sensor ill put that money toward used wheels and tires if I can find some.

wiring on this thing is a mess. Its really sad lol.

[Vigo]

That picture is so bad it's like you're ashamed of the car already.. hah.

Still doing anything 12v 3.0 related? If not i will buy your cams.

[boostedsohc]

Oh you bought that. I saw that on CL and passed on it. It should be a fun car though, get a transfer case brace for the transfer case and maybe if it hasn't been done, a bell housing brace too as they like to explode with too much power. Check the output shaft for excess wear and replace with 300M or Quadco.

MAFT is a pretty penny for the 3/S guys, but your timing is probably bad as the Flashable ECU has been replacing MAFT. Try to slip it in for around 220-260 for the Translator and the MAF and you might get a buyer.

[Vigo]

Good thing the Tcase doesnt explode from too many drivability problems or it probably already would have blown.

Too much power seems optimistic at this early stage.

[Sundance 6g72]

I wont be making big power. Maybe 400awhp. Tcase brace looks easy to fab at home, bellhousing is more involved.

Im keeping all my sohc stuff (including cams). IF this motor blows up somehow, im not against putting in a turbo sohc AWD. The car its self isnt perfect and im NOT proud of it (yet). I need to fix owners mistakes. The wiring is terrible (worst ive ever seen) and some of the turbo stuff is real ghetto. I dont need the car to be perfect looking but I do want a good engine bay.