I have myself one GSLSE engine, no intake manifold. Stock exhaust manifold. I'm hoping to confirm that I can use a larger cc injectors to cover a low boost (7-9psi) without the need to add aux fuel injectors. I am thinking of a square bore throttle body. As I understand that should give me better throttle response than a IDA/DCOE. If this plan has flaws, then I'll just go IDA throttle body, two in the block two in the throttle body.

 

Low boost from what turbo? A HT-18 at 9 PSI makes about 200HP. A GT40 at 9 PSI makes 350 HP.

Very roughly speaking, you need about 1200 CC of injector total per rotor to make about 250HP with some overhead.

There are 1200CC single injectors like ID that are controllable enough to idle the engine and be reasonable at light loads. This mostly depends on your EMS.

As for the throttle body it really depends on the purpose of the engine. In general for a street driven engine, you would want to stick with the progressive throttle system in the stock manifold.

 

Yeah, what turbo... My original plan was to go for a stock TII turbo as I figured they would be all over and cheap... So with that I'm still waiting. I have been looking at T4 turbo headers.. but there are so many options. I will admit I don't know **** about turbine engineering, but the amount of 19 year old street racing experts out on the internets is frustrating at the least. Back to the car in question. I guess I am building it as a "Show&Go" It will not be daily driven. You did answer my main question, and that is YES, I need 4 injectors. seems 2 could work, but 4 would be safer.

 

It all really depends on how much power you want to make and where in the powerband.

 

I have tried tying 3 times now, and I keep inadvertantly trying to talk myself out of a turbo. I'm only looking for minimum of 200hp, which as I understand it should get me into the high 13s for the 1/4. I was wanting the turbo for mid range grunt. From what I understand a stock turbo would serve my modest needs well. I just can't justify the cost of admission at this point. I hate when a reality hits you..

Also, Aaron... Kudos to your YouTube videos. I have been subscribed for a while. Thank you for the resource!

 

If you're shopping for used HT-18, watch out for cracked exhaust housings. These are subject to massive heat loads on a rotary & many have cracks in them. You can't buy a new HT-18 from Mazda, I bought the last one on the planet years ago...

Here's an example of a nice SE with a turbo (not mine)...

 

Yeah, I am thinking of this set-up on my FD to simplify and strip weight from 13B-REW in a racing class that requires stock short block and stock turbos almost everything else open.

Stock 13bB-REW short block
2x 2,225cc ID2000 in primary position in lightweight FFE rail.
JW Holley style intake manifold
PCE 4150 throttle body
Boost Hat

Divorced parallel stock twins (~420rwhp max)

I am thinking to run 70psi static fuel pressure with 1:1 boost referenced rising rate pressure regulator and stock pump feeding a Bosch '044 to handle the flow at elevated pressures.

Others have used the ID 2000 in primary position and it idles/revs fine.

What is your budget on the turbo?
At the end of IndyCar season the teams sell off their EFR 7163 for ~$750 for good ones. Nice SS V-band exhaust housing you can weld right onto if you don't want to buy V-band flanges. Turbo will do ~400rwhp on a rotary- should do 200rwhp easily at the boost you want to run.

I would make sure your fuel system can support the max flow of the turbo (not desired power level) in case you have boost control issues you won't have lean out.

I would go as far as dyno tuning it on 110 octane up to what the turbo can put out and then turning down the boost and using your pump swill.

 

sounds like a killer deal! where can i get my hands on one of these turbos? i too am planning on a turbo set up for my 85 SE.

 

or you can use a boost/fuel cut.... set it higher than you plan to run (if you want to run 10psi, set it at 12psi, something like that). every stock car in the world uses this, without any trouble, it is a valid approach.