how much boost?

[Need2Speed]

Hello all I have a 91 mr2 with a 95 jdm 3s-gte motor. I have all the JDM parts swaped in the car. I am running a full 3inch exhaust and cold air intake. The only thing on the car that is not JDM is the frame. I just bought the greddy profec boost controller and I wanted to know what is the max boost setting that I can set with out blowing anything. I have a race with a 3rd gen rx7 tt comming up and I need to win. Any info would be great.
thanx

[1QUICK2]

I see no problem with you running 15-18 psi. You might need to plug the MAP sensor to aviod fuel cut, but im not sure on the JDM motors. It has the CT20B correct? I heard not to run too much boost on that turbo for a long period of time.

[MR2Driver]

You heard that because its a Ceramic wheel...

I wouldnt recommend anything about 15 PSI without intercooling. Also dyno tuning of your AFM afterwards is a MUST

[scarecrowX]

Originally Posted by 1QUICK2

I see no problem with you running 15-18 psi. You might need to plug the MAP sensor to aviod fuel cut, but im not sure on the JDM motors. It has the CT20B correct? I heard not to run too much boost on that turbo for a long period of time.

from what i've read, the JDM 94+ are gen III engines. if you disconnect or plug the map sensor, the engine will not run. the gen III ecu's use the map sensor to calculate fuel/ignition instead of an air flow meter.

[1QUICK2]

Word. I know it ceramic, thats why I posted not to run much boost. Gen lll motors do not have AFM's and the car is intercooled stock Lachean. What do you me by dyno tuning your AFM afterwards, and intercooling it?

[JekylandHyde]

There is no way to tune an AFM.
And dyno tuning is not a must.

I also would not run over 15 psi without either: race gas, upgraded intercoolwer or water injection. Personally, I use all three and run 22 psi out of a bigger turbo

Not to burst your bubble, but I would not be optimistic about the race with the Gen3 RX7 (that is the last body style - correct?).

[scarecrowX]

oh, the gen III engines also do use the CT20B.

i'd listen to jek though.. people don't make 308rwhp by not knowing what they're doing.

if i were you, i would look into a decent water injection setup. do a couple 3rd gear pulls on the street with it turning up the boost REAL slowly and listening/feeling for knock or the ecu pulling timing because of knock (you likely won't hear it).

i'd also base the max boost setting on what the other guy is running. you both weigh about the same (FD's are 2700-2800lbs), and if he's stock, just turning it up a little should be enough. if he's heavily modded.. well.. just don't race him for money.

[HondaChili]

I agree, if you're gonna mod your car in limited time like this, the rx7 would prob do the same. Now i dont know too much bout RX7's but i think they should take bolt on's pretty good if not better than you. Considering it comes out of the box a monster already, and those babies almost has no turbo lag and can boost even a TRUCK turbo, I'd suggest not racing the RX7 unless you know its fully stock or at least with minimal mods. On the other hand if you dont care bout your car and you MUST win this race... A quick fix might be to spray. THATS ONLY IF YOU DONT CARE BOUT YOUR CAR. not saying that NOS is will blow your car, but for someone to use it desperately to win a race will prob damage the engine. just a thought.

[Need2Speed]

The 3rd gen Rx is not heavily modified. He has a couple boltons and he put up his boost. He is running low 13's. Ive been monitoring my Boost and at the stock setting it seems like im pushing between 15-16 pounds of boost at 5500 rpms. I will be using race gas, 106 octane. what do you guys think??

[JekylandHyde]

If he is running low 13s, I would say the cars are closely matched ... but I would say the favor goes to him since he has track experience in that car.

Getting an MR2 off the line is not the easiest thing in the world to do. There is a fine line between lagging/bogging off the line and spinning the tires.

Do you know your shift points?

[HondaChili]

Originally Posted by JekylandHyde

If he is running low 13s, I would say the cars are closely matched ... but I would say the favor goes to him since he has track experience in that car.

Getting an MR2 off the line is not the easiest thing in the world to do. There is a fine line between lagging/bogging off the line and spinning the tires.

Do you know your shift points?

I totally agree, i drag raced my friends EVO from stop and i have to admit it was one of my first races. Even though he bogged launching his car, i had just an equal share of my troubles. Most of the time i would peel more than id expect. I dont think that my problem is feathering the clutch but rather precise throtle control on take off. So before i go off on the subject... the point is to know your car better and see how much throttle u can push gradually so there wont be too much of a peel.

[Need2Speed]

I can honestly say that I have a little experience. I took out a 5.0 club who underestimated me, but yesturday I did a couple of quarter mile runs and I ran a flat 13. I kept on messing up my launch. I was lagging and launching at 2500 rpms. when I launched at 3000 rpms my tires spun like crazy what RPM's do u guys think I should launch at? By the way I was just challenged by a guy claiming he had a j30 with a stock 300z engine. What do u guys think about that??

[JekylandHyde]

Where were you doing runs?
I am guessing G-Tech runs? There is no way you were running 13.00 with the mods you listed (unless you have the CT20B turbo).
An expereinced driver could not hit 13.00 with your mods.

With your mods and perfect driving you are looking at 13.3-13.5 at 16 psi of boost.

Your launch sweet point will probably be around 5500 rpms, you should shift around 6600 rpms in 1st gear and around 5500rpms in the rest of the gears. (unless you have the CT20B turbo, not the CT26).

I have no comment on your other "challenge".
As funny as this may seem, I am really not that interested in beating someone else. I go to the track for my own enjoyment and improvement.
There will be always someone faster. So what?

[Need2Speed]

I have the CT20B turbo, I did a run today just to observe my boost meters and I think the most psi I can push is about 20 because at 22.5 the turbo lost a little power and I heard a knock. How much is the difference between the two turbo's???

[JekylandHyde]

The ct20b is significantly better than the ct26.
You should be able to shift at redline with that turbo and a 13.0 flat is much more reasonable.