Ok, heres the layout. I have a '89 T2 i am working on. Street ported engine from Atkins Rotary.
My turbo i sent out is now a T3/T4 Hybrid B Trim.
Factory ECU
Factory 550cc Primaries

My question is, what secondaries should i run??? I am trying to go ahead and put the right size in there now so i dont have to fool with it later on, which is now big deal but just trying to get it done the first time.

I have heard several differnet stories also so thats why i am writing to you guys.

Rx7Store.net tells me that i can't run a bigger cc injector with my factory ECU. That's not true, you can but i dont know where the limit is untill the ECU can't functtion it.

RC Engineering says i can go as much as 750cc on factory ECU. Now i think with the motor and turbo setup i have, 750cc should be enough. But i am not sure so plz guys for those who have tuned out there or know more info then i do what do you think???

 

how much power will you have?

 

I am hoping for 400rwhp. Which is a ver good possibility. 350-400 at 10-12psi. 15psi will be the max i will run and i will only run 15 at times in need....

 

can't you use an afc to fool the stock ecu into thinking you're running stock injectors?

 

400 rwhp is in my opinion a far stretch at 10psi. espacially if your trying to do it with stock injectors. i belive with single turbo pushing 12 psi you should see 315 to 340 depending on your tunning numbers and how far to the edge you want to take it. mine is pulling around 340 rwhp @ 14psi and with real safe conservative numbers ant like high 11s low 12s across the board in A/f ratio

 

yes i am going to use the Super Fc to fool the comp. I just need to know what secondaries to run? i don't want to run too lean. So far every1 is either using 720cc or 750cc with some what the same setup as i have. the 400rwhp i am hoping for will not be with the stock injectors. 400 will be with a lot of tuning and differernt secondary injectors.

 

WTF is a B trim? I'm going to speculate that you meant V trim.

Here is a fuel calculator you can use to see what size injectors you will need.

http://rx7.com/cgi-local/2ndgencalc.cgi

BTW, if you bought a V-trim hybrid, you won't make anything near 400rwhp.

http://www.fc3spro.com/TECH/MODS/TURBO/comphy.htm

 

i would like to know what turbo you're planning on running to make that power at that boost.

if you're shooting for 400rwhp then the stock ECU and a piggyback is not going to cut it, and you should get a standalone, some 720s, and some 1600s.

 

First of all you need a better fuel pump, then you have to be sure you are using the same impedance injectors. If the new injectors are not the same impedance you are going to fry your ECU. I was making 430rwhp at 16psi with 4 X 96lb/hr or approx. 1008cc/min injector at almost 90% duty cycle. The AFC has only a 50% control range over the stock ECU. So you are going to run too rich at idle if you want to make that kind of horsepower. I was using a stand alone ECU. The easiest way to solve this problem while keeping your stock ECU and stock injectors is using 2 additional 1600cc/min injectors controlled by an additional injector controller like the greddy rebic 4, the hks aic or the SDS additional injector controller. The SDS controller is the cheapest. I hope this can help you.

 

i have to say that 430 RWHP @ 16PSI is real impressive. never seen anything near that before. the highest ive seen at 16 PSI was 393 and that car was pushing the limits across the board.

 

I know someone who tuned a to4s to 460rwhp @ 15psi

 

Im correct when I said you cant run larger injectors on the stock ECU, but you didnt mention you were going to use a Super AFC That is doable up to a point. We have tried running 1600cc's with a super AFC and could never get the car to run that well. I would suggest running a microtech and 1600's

Jason

 

why is every1 running such big injectors. Every1 is complaining about running rich. Well hell yea your going to run rich when you are using 1600cc injectors with a something that does not need that much amount of fuel.

One of you guys mentioned for me 2 run a stand alone, some 720's and 1600's. That is WAY too much. First off, i like my factory 550's as primary's. you don't need bigger injectors especially for my setup. 550's should work fine, i mean they are only on at idle and low rev's. 1600 is WAY too much also.

My Point is, most of you guys complain about the car running like ****. Ever thought about getting smaller injectors?? Maybe your running just a bit too rich.

 

for those of you who might have gotten confused. i only ment to say that i am keeping my primary's as 550's. The secondaries possibly 720 or 750.

 

People usually run 1600's in the secondaries because most either need it or have a goal to reach a certain hp that requires them. Plus, they are easy to find, and cheaper than 720's.

Besides, many people run the 550/1600 combo. At 80% duty cycle, that equates to 495 flywheel hp. That means somewhere around 420rwhp. Now, I'm sure there are more than just a couple people on this board that are making 420rwhp or more.

Also, you are wrong about not needing larger primaries. Especially on S4/5's, the secondaries don't come online until 3800rpm. At around this point is where some people have blown their motors. This is why many people suggest running 720's all around as opposed to just 720's in the secondaries. Of course, with a stand-alone, you can take care of that and run 550/720's...

One more thing, running the injectors at a lower duty cycle means the injector does not have to work as hard. This means it does not heat up the fuel as much. Another benefit of running larger injectors and tuning them down rather than smaller injectors and tuning them up...

BTW, 550's primaries and 750's as secondaries will not flow enough fuel to make 400rwhp... not even with them held wide open. According to the fuel calculator above, that would get you around 375 flywheel hp. That is around 320rwhp.

Oh yea, what the hell is a "B trim"? Although it may be possible, I very seriously doubt you will go through with TRYING to get 400rwhp out of a hybrid. With the stock turbine choking up the motor so badly at near that hp level, your motor is even more prone to detonation.

 

I'm vaguely hijacking this.

I'm reworking the intake on a 4-port, and I'm thinking I want both primary and secondary ports to get fuel throughout the band, but I'm concerned the present 1680cc secondary injectors will perform poorly below 4krpm, so I'm considering milling additional injector sites into the secondaries. How insane?