TBIThrottle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.
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I will be swapping a 400hp crate motor into my 91 firebird and need to know if the 670 cfm throttle body from the regular 350 will work with that much hp? I heard that you can go with the Throttle body from the 454, but I have not heard for sure if that works. If so, does it plug in to the same plug? if not, what mods do I need to make for this TBI setup to work with 400 hp?
Thanks
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Last edited by dimented24x7; 11-28-2006 at 08:22 PM.
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Getting the TBI to work isnt a big deal. The holley unit will require that you swap out your injector connectors and TPS connector. The holley uses the old flat style TPS connector. You will also need another intake as your current one not only wont support the power but also has bores that are too small.
With 400 HP, though, the TBI wont be the big issue. The big issue will likely be the ECM. The stock computer wont be able to hack it. Neither will the aftermarket systems as TBI is somewhat specialized. (Im thinking of making this sticky material, so its a bit winded, but I think youll find it informative). In addition to the exhaust, intake, and other mods, you should consider upgrading your computer.
EBL: EBL was developed by RBob, who is quite talented, and was one of the first to really dig into the EFI computers. Based on the stock ECMs, its got lots of bells and whistles, runs cool fans, nitrous, calculates fuel economy, etc. and comes with an add on board for the stock TBI PCM that lets you use additional outputs as well as a high speed data link. In addition to the high speed datalink and included software, it also includes much needed improvements to the code to make it more performance oriented. The system itself is quite good from what I can see. The system is also very widely used, so there is a large knowledge base. Downside? The C3 TBI ECM is one of the worst ECMs ever made. Its tough as nails, but has only the most basic hardware and is slow. In addition the code is still speed density based, so the fueling will wander around with changing air temps and conditions. Lastly, it costs around $300
93-95 TBI PCM: Its the swiss army knife of EFI. Runs bank fire, batch fire, TPI, TBI, MPFI, and both the 4L60 and 4L80-E transmissions, and you could spend a year and not cover all of the stuff they stuck in it. It is also lightyears ahead of any other OBD-1 system and served as the basis for the later OBD-II PCMs. Downside? Its COMPLICATED, and still uses speed density. Tuning the more advanced items requires you to delve into the mysterious and convoluted world of closed loop feedback control.
93-95 TBI PCM with MAF: This is the system I developed. After five years of frustration with TBI, I learned that I hate tuning, I hate speed density, I hate the car not running right, I hate having to redo the VE tables whenever I change the timing, I hate it running like dog doo whenever I mod the engine, and I also hate alot of other things. I just want to turn the damn key and drive the car already. Thats why I made my own system using mass air flow instead of speed density with TBI. Its quick to tune, runs well year round without too much fuss, and seems to work well with engine mods. In addition, the code is FREE and open source, not to mention that its a true, high resolution fueling system. You only need to supply an LS1 style MAF and PCM from a yard. Downside? The MAF doesnt like varnish, and needs to be cleaned evey six months. In addition, you also have the complicated PID idle and transmission routines like the stock PCM. They work very well, but could be a bear to tune if tuning is necessary.
MPFI: Its the most widely used system today in cars, works well, and has lots of support. If youve got a well stocked checking account behind you and you know your stuff, the sky is the limit as far as horsepower goes. Downside? Some of the aftermarket intakes and other items can really put the hurt on your wallet and the stock TPI is restrictive.
Carb: Been in use forever, and everyones used it. Nuff said. Downside? Got emmisions, care about fuel economy, live in california? Also a carb is fairly bare bones as far as fuel control goes, and wont give the precision or smoothness of FI.
If theres one part of the car you cant overlook, its the ECM. This will make or break your setup.
Last edited by dimented24x7; 11-28-2006 at 10:53 PM.
Also, dont forget to read all the other stickies. There is a HUGE wealth of knowledge to be gained from those and they may even answer some questions that you didnt know you even had yet.
I ran the stock 7747, 299, and 8746, 6395 for some time with nothing more than Flash Chip adapters soldered in. Pain in the rear!
Switched to the EBL when it came out, I was actually a Beta Tester on it. With the faster dataloging, much more performance oriented code, and its tech support dialing in the combo was much more complete and I dialed in a cam that others considered impossible with TBI on a 305. I even went as far as to dial in a Weiand 142 on my modified 350 TBI using the EBL, a VAFPR, and 2 bar MAP.
I then switched over to a PCM (16197427) from a 1995 G20 Van. Great running setup for the 3 vehicles I have tuned with it.
Dimented24x7.....I have a question about the system you came up with. I am interested in trying it, but will the LS1 pcm work with the factory TBI setup, chip, etc? Also, how would you integrate the MAF into the TBI harness? I also wanted to know if I converted to this setup, would the GM hot cam work without custom tuning? Just want a little more pep out of my TBI, but without a lot of trouble. By the way, it's a 92 camaro with a 92 truck 350 TBI and computer.
What kind of things do you change to run a mild cam? I've been reading the forum non stop after i bought my ostrich and all i find is scattered information everywhere..
im 17 years old and i just bought an 88 Five0 camaro. i want to make big power but dont want to spend more than 1200 and can i keep the stock T5 5-speed or would i need a new tranny?
I am completely lost,, I do not understand how to switch over to a pcm and how to tune it I am gonna take out my 305 tbi and install my 383 stroker and I know I will have to do something I thought about the ebl but it seems really complicated then i started reading about using other computers but I am really lost....can someone explain this information for dummies Thankyou
I just bought a 92 RS with a 305 TBI. I started to replace the air filters with a K & N air filter, installed a Tornado device, replaced the breather, PCV, fuel filter and fuel pump and replaced the preheater tube. The car runs great and I'm saving to buy the component for a tune up and serviice the radiator with performance parts from Summit Racing plus many more projects are planned when the money is right. I want to know what high performance parts I need for my TBI.
What kind of things do you change to run a mild cam? I've been reading the forum non stop after i bought my ostrich and all i find is scattered information everywhere..
i put a mild cam on mine as well, the specs sheet indicates that an ADJUSTABLE fuel pressure regulator is needed.....i cant find one to this date......unless im looking at the wrong places :/
