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796spdbu
03-21-2005, 05:51 PM
Hey guys,
I just purchased a 91' tpi engine with a painless harness.The engine was rebuild and put into an s-10.The 700r-4 trans went bad and he sold the truck to me for a song.Heres my situation,I want to put this engine into my 79 malibu with my 97' six speed tranny.First can i swap this engine and trans with the auto tranny harness and computer.I dont really want to buy another harness and computer if i dont have to.can i fool the computer into thinking it is and auto if i put a toggle switch for the simulated park positionto start the car.I plan on running all autometer gauges.Second i think the car is speed density,what can i do to improve performance.I have been told that you can not do much with speed density.I'm not looking for 500H.P.but maybe 380/400H.P.Any help would be appreicated. :help:

Fuelie Fan
03-21-2005, 07:11 PM
Spend about 2 weeks straight reading the boards at thirdgen.org

The first limitation is of course the TPI intake itself. Making HP is tough becuase it's pretty restrictive above 4500 rpm on a 350. There are lots of aftermarket parts to help alleviate this problem. T

There's no limit to what can be done, HP-wise on speed-density systems. The limit is that you have to update the ecu anytime a significant change is made, whereas a MAF system can handle broader changes without any updates. This means heads, cam, or intake change could all possible require some recalibration.

As for the wiring and ecu, I don't think it'll be a big problem. You'll have to rig a p/n switch for idle control, as you mentioned I don't think it has anything to do with cranking, as I didn't have a p/n wired to my GM ecu for 3 years. You'll have to cut out the transmission connector. Not sure if you'll need the brake switch or not. The guys at thirdgen could answer all these questions. On the ECU side, you'll just need to burn a new chip (or have someone burn it for you). If you're comfortable with computers and fuel injection, I would suggest you get into burning chips yourself using Tunerpro RT or something similar, as I have had poor luck with mail-order chips for custom engine combinations.

Here's the wiring info and some ecm info, though a stock m/t cal isn't listed. Not a big deal, someone on thirdgen will have one.

http://www.diy-efi.org/gmecm/ecm_info/1227730/

And the link to tuner-pro

http://tunerpro.markmansur.com/

paul67
03-22-2005, 06:31 AM
If you did not want to mess with the comp it might make more power cheaper if you switching over to a carb set up because some times I read its not recommened to use auto engines on manual boxes and visa versa ?
paul67

gen3bu
03-22-2005, 07:02 PM
i use www.tunercat.com for my 355 tbi 93 sonoma. it ran a 14.2 on a stock cal, got it down to a 13.7 by the end of the season, but it still has more. it is a speed density system and i love it. from my calculations i am making @ 360-370 hp with all stock gm injection parts. the p/n switch is for starter engagement only, just hook up a clutch pedal position switch close the full pedal travel.
btw - my brother has a 1986 t/a 305 tpi mass air system. we built a 383, mild cam and afr heads. it pulled to 5200 rpm and ran 13.9's with no tuning. on the chassis dyno he put down @ 270 with a 700r4. he swapped to a big roller and lingenfelter super ram intake and did not see any improvment at the track, but he did lose some low end tq. the stock tpi is air flow limited at high rpm but it can still work great with the right engine package. i still need to tune his car though. it should make @ 425 and run low 13's. time will tell.

796spdbu
03-23-2005, 04:40 PM
thanks first to Gen3bu,I will most definatly check out the web sites. I have heard of them.Never realy checked them out.As for your truck i take it that it is a tune port.As for my car,I dont really think I'll be on the drag strip much.I building it to be a blast to drive in the twisties,maybe do a little track testing to dial in the car.The engine was rebuilt about two months ago,I would hate to tear into it but i thought about doing a vortec head swap with some kind of bigger roller.Not really looking for crazy horse power.I read chevy high performances' build on the vortech head swap,and they made like 420 h.p.That is what im wanting to do.Can i do this or would i be better of adding a pro charger? Thanks

Paul67,
From the begining i had planned on a fuelly engine.When i pulled the body from the frame,and have it sand blasted.I ran all -06 braided fuel line for the feed and return lines.thanks

gen3bu
03-23-2005, 06:21 PM
my 355 in throttle body injected. if you want to see stop by the shop some time.
511 home ave
xenia,ohio
ask for kevin

gen3bu
03-24-2005, 07:20 PM
btw - if you want it tuned or need help tuning it let me know. i can tune it in real time on my laptop. it is actually pretty fun.

:icon996: :revto9k: :3gears: :drive1:

Fuelie Fan
03-25-2005, 07:57 PM
I hate to get off topic, but I guarantee the ECU uses the p/n for idle control. I can also guarantee that my 7747 ecu started for years without a p/n switch input to it, I just recently wired one into the ecu becuase the hunting idle was driving me crazy.

Now, to clarify: I always had the stock P/N switch in the car (70 nova), as it does make the connection between the ignition switch and the starter solenoid. That is absolutely necessary. What I am saying is I don't believe the ECU will withhold injections if it doesn't see a p/n input, so if you can get your engine to turn over (using the stock p/n, bypassing it, or relocating it to your clutch pedal, whatever it takes) and the ecu is seeing an RPM signal, it will try to start the car regarless of whether the p/n switch input to the ECU is connected.

Also note that, at some point, the P/N switch design in GM vehicles was changed, but I don't know when. IF your 79 is wired the way mine is, then the p/n only sees +12V during cranking, so its useless as an input to the ecu at any other time. You have to use a relay in conjunction with the p/n to get the correct signal to the ECU. It may not be worth it to you, but it was bugging me so I did it. I can get you a schematic if you want. I came up with it myself then found out the next day painless sells a kit that does the same thing, oh well I saved some money!

69Myway
03-26-2005, 02:23 AM
Also note that, at some point, the P/N switch design in GM vehicles was changed, but I don't know when. IF your 79 is wired the way mine is, then the p/n only sees +12V during cranking, so its useless as an input to the ecu at any other time. You have to use a relay in conjunction with the p/n to get the correct signal to the ECU. It may not be worth it to you, but it was bugging me so I did it. I can get you a schematic if you want. I came up with it myself then found out the next day painless sells a kit that does the same thing, oh well I saved some money!

Did you run a diode on the line so the 12+ would not feed back to the computer during cranking?

nitrovette
03-26-2005, 04:21 AM
i modified a p/n switch from a fbody to fit on my stock shifter .
Heres a nice site to checkout tpi swaps.

http://www.chevythunder.com/index.htm

796spdbu
03-31-2005, 06:22 PM
Hey gen3bu,
Couple questions,first i finnally got the truck home to yank the engine and it has a mass air unit in line like my 95' camaro, so i think it is mass air instead of speed density.Can you help me tune it? Second you say your truck is throttle body,I have a 91' sonoma that I wanted to swap in 350 tbi,I heard that i can use the origanal 4.3 computer but use a 350 tbi chip,is this true?And finally I built a 355 for the wifies c-1500. It has vortec heads a crane roller with 509 lift,its the one jegs has in there catalog for the tpi camaros,the pistons are trw forged four valve relief. I did the swap like chevy high porformance did theres, except the cam is bigger,Im using the gmpp vortec tbi intake.I can i get a chip burned for it.The truck has an art carr 700r-4,richmond 4:10 gear auburn posi unit and moser axles.So this is going to be a real runner.....for a truck. Thanks for any help and I'll have to come up some time,thanks for the invite.

gen3bu
03-31-2005, 07:42 PM
Hey gen3bu,
Couple questions,first i finnally got the truck home to yank the engine and it has a mass air unit in line like my 95' camaro, so i think it is mass air instead of speed density.Can you help me tune it? Second you say your truck is throttle body,I have a 91' sonoma that I wanted to swap in 350 tbi,I heard that i can use the origanal 4.3 computer but use a 350 tbi chip,is this true?And finally I built a 355 for the wifies c-1500. It has vortec heads a crane roller with 509 lift,its the one jegs has in there catalog for the tpi camaros,the pistons are trw forged four valve relief. I did the swap like chevy high porformance did theres, except the cam is bigger,Im using the gmpp vortec tbi intake.I can i get a chip burned for it.The truck has an art carr 700r-4,richmond 4:10 gear auburn posi unit and moser axles.So this is going to be a real runner.....for a truck. Thanks for any help and I'll have to come up some time,thanks for the invite.

it sounds like the truck is a mass air system. we can hook up to itto tune it i think it will use the same def file as my brothers car. although we could make it run better and easier with speed density conversion. yes, if you replace a stock 4.3 with a stock 5.7 the stock chip is the only major mod needed for the swap (also need: bigger injectors, distributor, etc v6 vs v8 stuff). yes we can fine tune both the 5.7 tbi sonoma, and the c-1500. it is simply calibrating the fuel/spark cuves to match the new air flow. the c-1500 is built similar to my sonoma.
btw - it ran a [email protected] tonight at kilkare with a 1.944 60'. so there is a lot of potential to the gm tbi computer system.

kevin

796spdbu
04-01-2005, 04:13 PM
You have been a great help to me so far.You speak of speeddensity swap,what is involved?I'm hoping to swap the engine into the mali some time next week.If you think s.d. is better I'll go for it,as it requires less mess than the mass air.Can you suggest an alterations to the engine either internally and externally :worship: .I'd like to do the vortec head and cam swap.I'd like to get it running first and then this winter i'd like to do the changes that you might suggest.Getting a base line first would be idea to me right know.Id like to get it together for the pro-touring show in june :scared: As for the trucks,the c-1500 will be in the truck soon.Have you ever tried using an intake like a vic junior with an adapter plate for the tbi.I have thought about this for a while now.It seems that every one but you suggests getting rid of the tbi.Thank god some one else sees the potiental.I'll try to get up your way,what time do you guys close up there and are you open on the weekends?Thanks again :bananna2:

gen3bu
04-01-2005, 04:25 PM
we are not currently open on weekends, although someone is usually there. we close at 5:30, if you call the shop and i might be able to stay a little later. crane makes a 2030 compucam, it is very mild but has a strong torque curve. i also have a complete stock vortec roller cam with lifters, links and spider if you are interested (it is tiny though), the cam in my truck is similar to the gmpp lt1 hot cam. also afr heads are 4 thumbs up in my book and they are 50 state legal. i think the easiest way to install the computer is to get a computer and harness for a tbi truck to get the speed density. the 90-92 f-body's were sd too i think. let me know when you want to tune them.
kevin