NewmanFirstgen

I know someone here was planning on using a chevy TBI to get a cheaper injected 12a.. Any updates?? I am planning on trying this also in place of my holly 465.. megasquirt and a tbi would make tuning a turbo much easier... My Wideband is on its way, so i am trying to get some parts together for my project..

What size tbi should i get?? what cfm would be good for a na project going turbo soon?? one off a 350 chevy or larger?

FB II

i, personally, would think that a TBI setup would be insufficient for going turbo. in general you need alot more fuel than you would n/a... even of the same horsepower so you would have to utilize very large injectors. plus, they are restrictive and having only 2 injectors (i think, let me know if some have 4) you will have a hard time having good drivability and idle if trying to go for higher power due to the size of each injector because of the fuel neccessary for a turbo. if you were staying n/a then this would be a nice economical fuel injection setup. other than that tho, and you should stick with something more proven.

just my opinion

rrluthi

I was planning on doing this, but ended up swapping in a gsl-se engine.

Not only that, but the company that I worked for that had developed an ECU specifically designed for chevy TBI systems grafted on to different cars, went out of business. I still think it is a definite possibility however. I may do it at a later time. I still needed to work out fuel delivery, although I have a complete intake system.

A megasquirt would easily run this system as a standalone without spark control.

Given the ready availability of parts, if you get something together and work out all the kinks, it would be super easy to sell kits (wiring harness, fuel pump, TB).

NewmanFirstgen

Yeah only 2 injectors on a chevy tb.. and i think they are manufactured by holley.. and the injectors on the tbi are not standard size either.. I was looking at the tb's on rotaryperformance.com and was wondering if a dual ida style 50mm tb's would flow enough cfm for a turbo12a setup

rrluthi

Believe me you can get 4 barrell chevy TBI.

That's total overkill for a rotary. General rule of thumb is figure out how much HP you want to make, then design your system around that. Figure out the flow you need, search on google for the cars with the right size TB, and run to the yard. Grabbing a TB out of the junkyard for $25 is a lot cheaper than one of those IDA setups. Plus you can get every sensor you need for free. You can buy a Chevy TBI to Holley adapter on ebay, they are pretty cheap.

NewmanFirstgen

four barrel with 4 injectors?? I've only seen 2 injector tbi'2

Rx Seven

iTrader: (12)

I think the guys thats running the Chevy TBI screen name is autopaul.

FB II

the TBI setups you will find 95% of the time are two barrel. also, lets think.. this guy wants to boost on something of this nature....

tell me this isn't a restriction of airflow and under boost that it's not going to be a disruption...


that's just plain junk... n/a sure not bad. boost? i wouldn't waste my time when you can get amazing power AND drivability with a good carb setup.

Hyper4mance2k

iTrader: (40)

he was talking about this I have pix, but that's it, and I don't know who posted it... maybe it was autopaul

trochoid

iTrader: (6)

I think that setup in the pics above would work well, if he used a 13B center iron with the primary injectors and the ones on the intake as secondaries. I've been tossing around something along this line, but I don't want to crack open a 2k motor to change the center iron.

NewmanFirstgen

I was thinking of also welding injector bungs on the manifold.. but it seems it will be cheaper to go with the ida's.. only question is what size? In the end i want between 250 and 300 whp, this shouldn't be a problem with a turbo. I am just stuck between turbo'ing my 12a or converting a 13bt for use in my fb or locating a 12at... can't seem to find a 12at anywhere, a 13bt sounds good but i already have 2 12a motors and i'd like to keep these for spare parts and rebuilds if and when i need it..

so 12a turboed is the direction i want to go..
FBII I know that a carb setup will run good when you get it tuned right.. but i don't want to be breaking my carb open multiple times just to try getting things workable.. plus I think that once you get the carb tuned correctly, it's old technology.. the best tuned carb does'nt control fuel as well as a shitty FI set up.. and then theres the whole "Bogging while cornering" problems with the holleys. Even with a center hung float.. I don't want to spend a bunch of time and money setting it up only to find out that it is lacking on the track..

And as much as the Chevy TBI's look restrictive.. they made them for big blocks also I can't believe a tb set up for a 454 would be too restrictive for a 1.2 liter rotary.. and maybe the turbulence around the injectors would cause the fuel to atomize better?? lol dunno.. I wish Robert would just answer my email's he must be very busy..

rxtasy3

iTrader: (2)

u'll find the 4bbl throttle bodies on mid to late 80's chevy trucks. i too have thought about this, but have decided that with the rb holley intake, i'll be using that 4bbl throttle body that someone here has used. i think it's like a 1000cfm and i believe it was like under $200. anyone know what i can get the MS already built for or anyone here building them and what u would build one for?

NewmanFirstgen

Where can i find this 4bbl throttle body under $200? Does it have provisions for injectors? i've been searching and searching.. My only concern with something this big is velocity of the air going past the injectors.. Would this cause a hesitation in the low to midrange rpm's?? I feel too big a throttle body may effect drivability but don't know for sure...

FB II

i'm not saying to not use fuel injection... i was just comparing to a carb that's all. my point is Throttle Body Injection is restrictive. that's it.

the 4 barrel throttle body you guys are thinking of is the one i almost used, made by Auto-nomics.

http://www.auto-nomics.com/cgi-bin/s...part=12168-001

NewmanFirstgen

Yeah that one looks nice.. Adjustable cfm with the bore inserts. I think that may be the answer.. now 1 more question...
Does the s4 or s5 CAS fit the 12a??

trochoid

iTrader: (6)

Both.