hello, first off let me say that i do not even own a third gen but got referred here by some fellow members on ls1tech on advice on tpi or tbi setup. I do love third gens and just recently sold my heads/cammed/stalled/n20 fourth gen TA. I have built and worked on several ls1 projects and several older carb setups, and so on. I tired to skim through you guys stickies real fast so if i post up something that has been answered before..feel free to direct me to that thread. What i have is this, i have an 88 chevy pickup that i want to convert to tpi or another tbi. It was orginally a tbi truck (obv) but it was worn out, the harness was starting to fail,and it just plain had too many miles on it. I opted to throw a cam in it, holley 600 carb, and old style hei. I know the tbi heads are ****ty, but it was a quick fix. I am wanting to swap the heads for better ones and was wonering about the camshaft i have. Now i have read, and read, and read some more about the "biggest camshaft" you can put in the tpi/tbi/lt1 etc..what i really would like to do is buy a realatively inexpensive tpi setup or equiv and throw it on there and be done. I want to know is my camshaft going to be able to be tuned to run smoothly with the stock speed density system. I know it will require custom tuning but i dont know if its even possible. ive read about having to make so much vacuum at idle to work effectively and i belive this camshaft falls right on the edge of the required vaccum. I would not throw out the tbi setup idea either. I just want to avoid having to go with an aftermarket ecu such as a Gen VII setup that will be ungoldy high $$. I have looked hard at the accel stuff but came to the conclusion i dont want to spend that kind of coin, nor do i want to for the F.A.S.T, holley, or any of it. Thats why i want to know if there is somene out there that can tune this thing to run. This will not be a super high horsepower racer etc..like i said , its going in a 4x4, daily driver, with the cam that i will post a dyno graph of and specs, headers, decent set of heads, and your regular mild stuff. I DO not want to swap this camshaft out, i love the power curve of it, its fairly new, and has a great idle. I know its only a 110 lobe sep and that is where i think is going to be the problem..any advice would be appreciated..i belive that if i cant stick with this cam, and stick with the stock efi systems, whether it be tb or tpi, i will just replace the heads and keep the carb. If it helps i still have the ecm and stock tbi. If it was possible to make a chip for it, i guess i could have the tbi rebuilt with bigger injectors, and have a chip burnt. i dont know..im just trying to get going in a direction before winter gets here so i can work on it on my downtime..
thanks and sorry so long
matt

here is the comp dyno sheet for my cam
http://www.compcams.com/Technical/Dy...62H-10_001.asp

if all else fails, ill have no choice but to rip it all out, and put a late model 6.0 in it..it has crossed my mind..more than once

 

Well, welcome to the forums! One of the greatest part of TGO is the DIY PROM board and its faithfull following. There are alot of people on these forums that share the same feelings regarding thousand dollar aftermarket ECM's and stuff. Because of this there is a large following of DIY ECM tuners, and this has branched out to include ALOT of different types of ECM's used in different applications. This has also resulted in better tools we can use to DIY tune, its now at the point where there are DIY romulators and flash PROM's so you can tune and datalog in real time at the same time, and update the PROM in real time via the flashing equipment. I would say there is a very good possibility you will be able to work with the stock ECM that came in that truck (if it is still there). If not you have the option of running a different ECM that might be better for your application but keep in mind you might also need to change the older style HEI to work with the newer EFI setup. You mentioned TPI and Speed Density so for that application you would be looking for the proper wiring harness and 730 ECM for speed density TPI. But regardless of what route you go, I think you should be good to go on the tuning side. I know there are a few people that are currently tuning their TBI equiped cars/trucks and ALOT of people tuning the TPI stuff (165 MAF and 730 SD), I'm sure it will be possible to properly tune the car with that cam. If vacuum is an issue you can get one of those vacuum canisters to help out. Good luck!!

 

yes, now that im a memeber i can search posts and look around a bit,,I have found that it would be possible to tune although i havent got that far on what will be needed. Im sure i can read the stickies and find out. Im used to the ls1 stuff where its just grab a laptop and go, or the older stuff where you need a screwdriver.. I kind of jumped generations ...haha..i was just wanting to get some good advice on what to get before i started..i mean since i was pretty determined to get the fuel injection, i was going to end up spending a crap load of money on one of the aftermarket setups. That means that there is no reason why i should not get the best factory setup that would work the best with what i want to do for cheaper..I will get the computer that is recommended, as well as the setup itself..that is why i joined to get some info on what i needed..Im sure i can work on the tuning end of it, or if all else fails, get someone to tune it for me..i just want to have an idea of what ecm and system will work best, or work at all,,.be it a tbi or tpi..i need to start hunting for one.

 

I'd at least go with a 112 LSA, if not a 114 to smooth out the idle.

 

well..i would like to think that that is not an option, i would like to keep the cam i have. The question is, can this cam be tuned by someone who knows what theyre doing , to run good. All i need to know is yes or no. If it cant then i will just have to wait until i can afford a dfi setup or just keep the carb..
matt

 

You won't ever be able to tune an engine, to circumvent that part though. You can only "tune" for certain things to maximize power, mileage, emissions, etc. You basically tune an engine to operate at it's peak, like they all should be. It really only adds fuel for power, or subtracts it for mileage and cruising. The cam design is a mechanical thing that you can't alter by tuning. I ran a VERY mild cam in a Monte Carlo, with a 114 LSA, and only 210 @ .050" on the intake. I had a 2.41 axle, a TH 350, and Holley adjustable TBI. It ran like a champ, and got great mileage, because it had so much torque off of idle. I couldn't believe how strong it was from a stop, considering the axle ratio. It couldn't spin the tires much, but it just went!

 

????? I didnt really follow that post about the cam being "mechanical" ..if your referring to there is no way to fix the 110 lobe seperation becuase its ground into the cam, i am well aware of that..i realize that a 112 would work but there has to be people out there that have smaller cams , such as the one i have running a 110 and driving it all the time..i realize its not going to idle smooth...its going to have a lope, but i refuse to belive that you cant tune it out..hell i had a 231/231 .598 cam in My TA,, we tuned it and it ran flawlessly, not surging or loading up at idle..it WAS on a 112 lsa but still considering, it was a decent size cam. There are people out there running waaaay bigger than that and driving them daily..I know i am referring to an ls1 engine with a computer that has a little more tunability that the older speed density stuff. I will try and read some more here and there..thanks for everyones replies.

 

Might be a good idea to make a post in the DIY PROM forums and ask the experienced tuners what they think about DIY tuning with those cam specs you have. I'm a NOOB at tuning so I dont have any specific answers, just a general feeling that there is a good chance it can be done. Also keep in mind you dont have to run the TPI intake with the 730 ECM Speed Density setup. You can use that same Speed Density system to manage other types of intakes, like a modified LT1 intake or a Holley Stealthram. Might as well go with the intake you want from the start. Probably want to get the intake that matches up the best with the cam you want to use (low end power go TPI, high end power go with LT1/HSR, etc, etc).