The concept behind my build will be to have good(but not too much) power, have the car drivable and reliable. I beleive this is possible if all the support mods are done ie. wide tires, suspension, brakes, reliability mods (cooling, grounding, good parts, solid hoses and braided lines, good tuning)and a full microtech standalone.

I want the engine to retain a stockish quality of craftsmanship, ie... matching the turbo to the motor and matching all the other parts so everything works well together. I am still debating between a gt35r, 99 spec twins. Im looking for 350-400rwhp and good torque numbers (320-380).

Becuase i live in a mountainous area it is kind of important to me to have decent power under 3000rpm. This is why im still concidering the 99 specs.


Can a gt35r be drivable under 3000rpm?? Does it boost at all under 3000rpm and how much? Which will be more reliable and cost effective? Do the 99 spec twins boost creep even with ported wastegate??


-Ben

 

The only problem with spending the money for the 99spec is if down the road you want more power like most people do. When building an rx7 you should try to do everything right the first time. You may want to look into bnr's

 

If you want the best all around package, most reliable, and least amount of heat, get the GT35R. Your gonna be generating alot more heat with the twins, plus with all the damn vacume lines and selanoids that go bad all the time. The twins are more of a headache than they are worth.

 

I had 99 spec twins for a while and they were nice but not for the money. I am single turbo now and much more happy. I think you should go with the 35r, maybe even possibly look into the t3 35r kit.

-Austin

 

what about air pump? if u deceide to keep emission?

 

Electric or relocate

 

No emmissions, no ac, probably going to keep PS, havent decided on the OMP.


And im planning on running it 100% on 100 LL with premix.

This is the thread that will hopefully solve my dilema.



Thanks,

-Ben

 

So I just finished my gt35r singel kit and Im very very very happy i did it. Spools rediculously quick and comes on strong, sounds amazing, vacuum is easy, heat is down and everything seems solid. Although i love the twins I cant say enough about this single set up. Pluss the motor longevity depends on your goals. Look at it like this you put on 99 spec twins and boost 14 lbs tuned and make around 320-340 depending on modds. With a gt35 kit at 14 lbs youll make more power more torque and it will put the same stress on the motor.

Chris

Chris

 

I am planning to keep my air pump is there a kit that keep the air pump.
Khris

 

A-spec makes one check with them.

Chris

 

that post made no sense. if you are making more power and more torque, then there is more stress on everything.

 

More power and more torque means more stress on the drivetrain not the motor. What breaks down the motor is pressure and heat. Less pressure on the seals from being able to run lower boost levels to get the same results. Less heat from more efficient parts. This is why it is important to make sure your temps. are maintained and low ( Water, Oil, Air ). Just for example, if I was to run untuned at 12 lbs of boost and have crazy detonation, High EGT, and horrible A/F ratio im going to make less power and put more stress on the motor. Now if I was to get that same setup tuned properly at the same boost with everything in line im going to have little detonation, good EGT, Efficiant A/F ratio and make more power and have less stress on the motor.

 

yes, but your other post didnt make that type of comparrison. it was comparing turbos at different boost levels and your above post was comparing tuned and untuned. two totally different ball games.

 

Although I understand what you mean this is my point, 12lbs of boost on eighther turbo will put the same pressure on the motor. 12lbs on the stock twins is the same as 12lbs of pressure with any other turbo pressure is pressure. Just becaue the turbo makes more power doenst mean it excerts more stress.

 

i think we were talking about two different things. what i meant was since its making say, 50 (i know it may be more) more hp at the same boost, yes the pressure stress exurted on the engine may be the same, but the torsional forces that the engine puts on itself from the cumbustion cycle would be greater. are we on the same page now?

-masin

 

I have a customer who wanted the same deal, a little more power with great spooling and more reliability. He went A-Spec GT35R T3 with the .72 AR turbine instead of the 1.06 like mine. Mine reaches full boost (15.5psi) by 3600 rpm.

My engine has the stock air pump on it with my own custom new bracket to move it higher. I have passed TX emissions for the ywo years by replacing my MP with a cat at inspection time.

 

You totally wrong sir. 12psi out of the stock twins is NOT the same as 12psi on any other turbo. Its called "CFM". And 12psi out of a larger turbo will put more stress on the motor.(although nothing is going to hurt a motor at that low boost level tuned right).

 

^^^Ditto!

 

Does anybody have a dyno run graph of a gt35r setup with boost vs rpm info?? I want to see waht it boosts at differant rpms.


Thanks,

Ben

 

From what I've seen, a T4 35R will usually see about 1 bar boost around 3200-3400 rpm. My 500R (35r hotside with larger comp wheel) sees 1 bar around 3700ish rpm.

 

Spool-up is also affected by your wastegate spring. The heavier, the quicker it will be. My Tial F46 came with the 7lb spring. Changing it to 10lb increased spool-up by a couple hundred rpm.

 

That seems pretty decent. So im assuming that at under 3000rpm the turbo boosts around 7psi?

The reason why im so concerned about spool time is i am emphasizing my build on drivability and reliability. I want to keep a stockish quality of craftsmanship. I also live in a mountainous area, i dont want to have to drive in boost all the time.

My goal is only 350-400rwhp at the most. Suspension and brakes are also high on my list.

-Ben

 

I can see how that works. I wonder if there is a way to actuate the wastegate right when you want it to. A spring will obviously flex slightly prematurely. The only thing that comes to mind is an electronic wastegate actuator with a boost sensor that activates a servo at a set boost level, not sure if their is such thing. However im sure there is some mechanical way to acheive this as well.

-Ben