fredtoast

I have a 98 ITR with a jrsc. I love the way it runs, but it has close to 70K on it, and I'm adding 25-30K every year. So I am already thinking about what I'll buy in a couple of years.

I wasn't addicted to FI when I bought the R. Since I'm going to boost whatever I get I'll probably drop down to a GSR. I know that turbos are more efficient at high boost, but I will be staying under 10 psi. I've been told that since the sc delivers the power quicker then the total area under the dyno graph curve would be greater for a sc under 10 psi. There are thousands of threads about turbo v. sc, but I've never found the definitive answer to this question.

I know that some of you have driven both turbo and jrsc cars. I'm looking for your opinions, but only if the levels of boost were the same. So I am mainly looking for comparisons to the small, fast-spooling turbos that one would select if staying under 10 psi.

I know that there are many other issues to consider including price, reliability, adjustability, et cetera, but I am just trying to answer the power question at this time.

I don't take my car to the track. It is a daily driver, but I drive it hard. The main weakness of a 1.8 is the power down low. That is one of the reasons I originally chose a supercharger, but now I hear that these small turbos spool so quickly that there is very little lag. Does anyone have any dyno graphs to prove this?

roadrunner

Here's my experience with both...

I have a GSR with JRSC @ 8psi, and it produces close to 90% of it's max torque by 2000rpm, and it stays constant until the fuel cutoff at 8400. Mind you, this is using a Hondata so tuning is very much the reason behind this, but there are also design features of a positive displacement supercharger. I also have a 944 turbo that can said to have plenty of lag, not much happens until about 3500, but the torque output will begin dropping well before the 7000rpm cutoff. There is no comparison between the two as the 944 would destroy the GSR, but it's not too fun if you do 140 miles a day in traffic.

Now compared to an 93 RX-7 of which my friend has, I'm impressed by the responsiveness of the turbos, but one thing that I couldn't stand was no matter how responsive the turbo was, it was never in direct proportion to what my foot was telling it. It was not enough for a moment, then too much, and it got even more tiring than my slow responding 944.

My JRSC GSR most closely responds like a bigger engine would, and I just use my foot to control the power, and I can do it without overshooting it most every time. Is it the fastest? Nope... but if I had to balance a car in corner, which is what I do much more often than going up against someone off the line, I would want either N/A or a positive displacement supercharger (Roots, Lysholm, etc). I guess it's the control freak in me that would not want the car to control me...

JRSCCivic98

I could not have said it better myself!!! AMEN to that!

CRVRX

When tuned the supercharger set up is great. one of the draw backs to the JRSC is the discharge temps, The other the fuel managment.
With a Hondata or similar computer you can tune out the tip in problems, and A/F problems . Once tuned propely you can make torque at any RPM any time you hit the gas, It will feel like a bigger motor rather than a boosted small motor.

In most cases the limits to the blower is about 10PSI on a 1.8L, which has a exit temp of around 220 F. If you spin the blower much faster the boost goes up and so does the temps, Which doesn't make much more power and makes it harder to tune.

Now a small turbo and correct size piping will spool very quick and can be sized to run 10psi, Reliabity will be no problem if done right. With both seups tuning is the key.
For instant power, any RPM , I think the blower has my vote. I have built and driven both and the blower is sitting on my car.


[Modified by CRVRX, 4:49 AM 1/17/2003]