7747 questions

[1985gmcsierra]

Will the 7747 support over 300 hp on a chevy engine with some modifications to the computer only?

[Fast355]

Will the 7747 support over 300 hp on a chevy engine with some modifications to the computer only?

A stock 350 TBI unit will not support much over 210 HP without modifications and a stock 454 TBI unit not much over 250 HP. The small block TBI in terms of airflow is good to about 275-300 HP at the crank, but the fuel deliverly is not. You will have to put an adjustable regulator or larger injectors.

[lionelhutz]

Do you mean the whole TBI setup (throttle body, harness, sensors, ECM) or just the ECM itself? The ECM will support over 300hp if you put together an induction system that will also support the hp.

[Skinny Pedal]

ECMs are exponential when it comes to power, it just depends on who is pressing the keys. Where TBI falls short is total air flow in CFM and total fuel in LBS. You can increase CFM by going BB tbi and or enlarging the bores. For fuel its injectors and pressure. If you are slick you could run multiple TBI units but that goes back to who is pressing the keys.

[1985gmcsierra]

ok.. i should be more specific.
I've read a LOT of information that could be incorrect.. so I would rather take advice from people on this forum who know their stuff inside and out.

So... if I wanted to make 300 hp at the wheels I'd have to increase fuel delivery and air delivery...

fuel delivery would be> increasing the fuel pressure with a better, more powerful pump and an adjustable fuel pressure regulator??

The question I have is? If you rebuild your pressure regulator to be adjustable on the tbi unit itself.. how do you read pressure on the tbi inlet? IF the regulator is in the tbi throttle body itself how are you going to read the fuel pressure in the unit?.. or do you need to just be aware of fuel pressure being admitted to the tbi throttle body?

also> how can we increase air being admitted to the tbi throttle body?

Which tuner software do you guys use? I've reads that Moates sells the proper hardware to get into tuning on your own.

Apparently tuner pro works well and tuner cat. Which is recommended?

Did you guys purchase the zif socket from moates, the G2 emulator, and all of that? how do you guys tune your ecms?

Also> did you guys do any reading outside the forums to know the order of operations of tuning to become confident in tuning an engine properly? what kind of engines are you running on TBI?
DO YOU GET DECENT MILEAGE?

[buddrow]

You sure have a lot of questions lol. But the gang here likes questions so I'll give you a little info.

1. Increasing fuel involves many factors. You can increase fueling through tuning of the ecm, changing of the injectors you use, i.e 5.7l injectors to 7.4l injectors, and/or install a higher pressure fuel pump(requires an external regulator).

2. Fuel pressure gauge: install the gauge on the fuel inlet line.

3.Increasing air to or through the throttle body. several cold air setups are available for our tucks, hp air filters, etc. There are also modifications you can make to your throttle body casting that will help increase airflow, search "ultimate tbi mods" and you will find a wealth of info on the subject.

4. I, and most everyone here, use TunerPro software as a general rule I think is safe to say. It is a very nice piece of software. As for hardware, I installed the G2 adapter, bought a chip burner on ebay and have been having fun ever since. I have no personal experience with Tunercat so I cannot comment on it.

I have learned much by reading here, as well as jumping in and trying things out. If you like challenges its very rewarding. :-D

Enjoy your visits, may they be fruitful.

Buddrow

[1985gmcsierra]

OK... just a couple more questions. And THANKS everyone for the quick responses. I really appreciate it and its so rad man. The guy at the junkyard laughed at me "pfft this thing is useless" as he looked at my 1227747 ecm. I said "yeah.. maybe you're right"... ;). I can't wait to get ripping around with solid performance and tuning it all diy.

Is it possible to install 454 injectors into a 350 tbi throttle body? if there were any modifications what did you do?
IF there's already a thread maybe I can check that out. The reason I ask is that I've read comments on forums saying a 454 tbi throttle body is tough to make work with a 700r4 kickdown cable. Any experience with this?

Also- When you use tuner pro do you just dive in? what's a good set of guidelines?

How do you figure out what your ideal pressure range is? If you wanted to build a higher performance small block chevy and wanted 300 hp at the wheels do you just experiment?
Or is there a general guideline as to what's a good starting point for a higher pressure fuel pump, injectors, pressure regulator? Any personal experience you guys would be willing to share?
I will read the ultimate tbi mods

[fastacton]

Yes, you can put 454 injectors in a 350 TB and vice versa. The 700r4 TV cable attachment is actually pretty easy, just cut that portion off of a small block TB and weld it onto the 454 TB. It works fine on mine.