TPI on TBI PCM

[Fast305]

Guess what guys, it works very well. All I did was jumper the MPFI select in the Memcal and start with a CPI 4.3 tune. Added in the Spark and Fuel tables from a 92 TPI 305/A4 camaro. Let men know what you'll think. Keep in mind this is a mildly built 305 pulling around 5,500 lbs.



I think it runs pretty good (she gets up VERY GOOD for a 5,500lbs girl). Kinda hard to compare with the top-end HP nature of my old 350 Vortec, but it does well in the low-mid range with the TPI and the very conservative production LT4 cam. I am still pulling timing out of the tune as it is still getting run-away knock counts right after the transmission upshifts. Its definately knocking, it knocked so bad I could hear it the first WOT 2-3 shift it made. As I pull timing, it gets quicker and pulls harder.



PS- My speedo is about 5 mph slow because the P295/50/R17s are larger diameter than the stock P225/75/R15s.

Still waiting on Photobucket.com. Atleast its faster than Youtube and the audio stays in synch though.





Right after I did that, I had a police car come flying up on a side street a couple of blocks up. Took a look around. I passed right on by. If I had been in a Camaro he would have had his lights on and been behind me.



Babying it a little up the steep on-ramp. Caught up with the guy in front of me and had to let off. I got some wheelhop on that moderate launch. My comment was because I thought it was just going to sit, spinning tires. It fought for and achieved some traction though and picked up and went.

[91chevZ71]

Where did you get the TPI parts? junkyard or ebay or whatever?

[oldred95]

Originally Posted by 91chevZ71

Where did you get the TPI parts? junkyard or ebay or whatever?

I'm always wondering the same thing.

[94Blazer383]

Wow, sounds like it runs pretty good. Where is the jumper you are talking about?

Whets the broadcast code and mask for the 4.3 CPI?

[Fast305]

Originally Posted by 94Blazer383

Wow, sounds like it runs pretty good. Where is the jumper you are talking about?

Whets the broadcast code and mask for the 4.3 CPI?

The Mask is $0D, I used BNBH which is a 1995 CPI 4.3 Astro/Safari Van.

[91chevZ71]

Are you running MAF on that 305? Is that a cold start injector TPI rig?

[Fast305]

Originally Posted by 91chevZ71

Are you running MAF on that 305? Is that a cold start injector TPI rig?

I ran it with MAF, but Dimented and I decided that his code was actual tailored more toward the TBI. So I went back to speed density.

It had a cold start injector, but got plugged along the way with what looks like an Accel kit.

I bought it off the TGO forum for $100. I bought the LT1 injectors off TGO for $37.50 shipped. Bought a throttle body for $35.00. I found a new gasket kit at autozone for like $25.00. I re-used the stock chevy van throttle cable. Had to buy a TPI TV cable though for the transmission ($18.99)

EDIT- Added some pictures of the setup and mockup of the TPI from the beginning.

[91chevZ71]

very efficient. How about the wiring, all DIY?
Since I was 15 I have always wanted a TPI engine...
7427 ecm, right? or 7730

[Fast305]

Originally Posted by 91chevZ71

very efficient. How about the wiring, all DIY?
Since I was 15 I have always wanted a TPI engine...
7427 ecm, right? or 7730

7427. I zoom in on the TBI PCM in this picture. 7730 has 3 harness connectors.



LoL, I've wanted one that long too. Had a 1994 G10 van with one, but sold it. Had one on my 1983, but put a complete 350 TBI in it. Now it has gone full circle to TPI again.

Wiring was simple. Cut the injector harnesses off of a couple of 2.8 MPFI camaros in the junkyard. I also robbed one of the cars of the TPS and IAC connectors with about 2' of wire on each. I created my injector harnesses a little weird. My TPI setup does not batch fire complete banks like all the others. I modeled the injector harness off of a TBI dual plane manifold. 1-4-6-7 all fire from the left injector driver. 2-3-5-8 all fire from the right injector driver. This puts the injector drivers feeding the same cylinders as a TPI engine. I then lengthened the TPS and IAC wiring. The CTS wiring was long enough on the van to drop down from near the thermostat housing on the TBI, to the front of the TPI manifold. Took me about 2-3 hours to piece all the wiring togather, solder everything, heat shrink everything, and add wire loom.

I am leaving on a 500 mile trip in it tommorrow.

I do know the 305 TPI will vaporize the 295/50/R17s at will.

[94Blazer383]

Originally Posted by Fast305

All I did was jumper the MPFI select in the Memcal and start with a CPI 4.3 tune.

I took my Memcal apart and did not see anything obvious to jumper? What did you have to do to the Memcal?

[Fast305]

Originally Posted by 94Blazer383

I took my Memcal apart and did not see anything obvious to jumper? What did you have to do to the Memcal?

http://www.hptuners.com/forum/showthread.php?t=9228

[94Blazer383]

Originally Posted by Fast305

http://www.hptuners.com/forum/showthread.php?t=9228

Nice....Thanks. I did some research yesterday over at TGO and found some posts about this. It also seems that this mod will make a v6 memcal work for a v8 in the older computers like the 730. Which I am going to use in my boat.

[Fast305]

Originally Posted by 94Blazer383

Nice....Thanks. I did some research yesterday over at TGO and found some posts about this. It also seems that this mod will make a v6 memcal work for a v8 in the older computers like the 730. Which I am going to use in my boat.

I personally would not use the 7730. The 7427 is a more powerful PCM and would tend to run your engine better.

[94Blazer383]

So, lets say you are running 26# LT1 injectors on your setup. What value would you put in for the injector constant? Since you were running 2 60# TBI injectors. Would it be 26X4=104? So it would be like having 2, 104# TBI injectors? Or would you just plug in 26#

[Fast305]

Originally Posted by 94Blazer383

So, lets say you are running 26# LT1 injectors on your setup. What value would you put in for the injector constant? Since you were running 2 60# TBI injectors. Would it be 26X4=104? So it would be like having 2, 104# TBI injectors? Or would you just plug in 26#

No, it is per bank. IIRC the injector constant for my 24# LT1 injectors, running at the stock 46 PSI of my STOCK fuel pressure regulator, gives 98.72 lbs/hr per bank.

One other thing, the main reason I recomeend the TBI PCM is that the V8 7730 and V8 memcal are now bringing $$$ on Ebay due to the fact they were only used for 2 years by GM and EVERYONE with TPI or even MPFI swaps, wants this ECM.

I set tne injector constant, plugged in a 1992 305/A4 timing and VE table (filled in gaps where needed). Then started logging. My tuning is not all that far off from the stock TPI VE and timing tables. The only exception is that I had to pull massive amounts of timing down low because of how well the cylinders fill at low-rpm and the 305s high 9.6:1 compression.

[94Blazer383]

Originally Posted by Fast305

No, it is per bank. IIRC the injector constant for my 24# LT1 injectors, running at the stock 46 PSI of my STOCK fuel pressure regulator, gives 98.72 lbs/hr per bank.

One other thing, the main reason I recomeend the TBI PCM is that the V8 7730 and V8 memcal are now bringing $$$ on Ebay due to the fact they were only used for 2 years by GM and EVERYONE with TPI or even MPFI swaps, wants this ECM.

I wish I would have figuered this out before I bought a 730 ECM on Ebay for the boat. I might sale it and try to find a TBI ECM. Other than 94-95 fullsize trucks what else did they come in?

Nevermind, I found it


$0D-16196395 or 16197427, 94 - 95 C/K Truck, Van, S-10 LN2 (16168505), 4.3L, 5.7L & 7.4L

[91chevZ71]

I think I'm gonna rebuild my old L05 and pretty much do the same stuff you've done to your 305. TPI, port heads, LT4 cam, maybe stroke it.

[Tbi-MAX]

Originally Posted by 91chevZ71

I think I'm gonna rebuild my old L05 and pretty much do the same stuff you've done to your 305. TPI, port heads, LT4 cam, maybe stroke it.

i love my L05 block in the burb, and my 95 pcm is the shiznitz...

hey FAST305, what will be your next TBI setup??

[Fast305]

Originally Posted by Tbi-MAX

hey FAST305, what will be your next TBI setup??

http://youtube.com/watch?v=yK2agWA1zhw

[94Blazer383]

Originally Posted by Fast305

http://youtube.com/watch?v=yK2agWA1zhw

Thats funny as hell.....