Intriguing question for you tech nuts...

[Riceburner91]

Hey guys! How's it been going? Been a while since I've posted but..I got something eating away at me..so here goes.
I have a 97 'Lude SportShift and am pretty set on a JRSC or an Endyn if it ever comes out. I will be rebuilding my tranny with the Level 10 PTS Kit and the Level 10 Torque Convertor will be going in at the same time. I believe after the rebuild and maybe a better tranny cooler I will have no fuss from that part of the drivetrain under boost. Since there's not a pulley kit for the Prelude and who knows when it will come out, I've been thinking about something kinda different to get more power. Yes I know I could do a turbo and am keeping it in serious consideration. But what about an engine rebuild with Arias pistons, titanium valves, springs and retainers...but with a HIGHER compression ratio. Like instead of the stock 10:1 maybe a 10.5:1 then port and polishing along with port matching everything. And then other things like throttle body, performance cat. convertor, ignition and fuel addressed as well. With proper tuning of course, what could I expect out of this and is it feasible?? Most go to lower compression when boosting but with only 6-8 psi I'm thinking about other ways of power....Please any feedback from you guru's would be great.

[pvang31019]

you don't need any of that stuff for 9lbs...that's sissy boosting. You just need enough fuel to feed the need

[fritz_269]

Both FI and higher compression increase your hp but they also increase the probability of detonation - a real engine killer. The only answer for that is good engine tuning and high octane gasoline.

It seems that the stock H22A can take up to around 6 (maybe 8) psi with just good tuning on 92 octane pump gas. If you want to raise the compression by 10% (say from 10 to 11) you'll get around a 6-8% hp boost, but you'll need about 10% more octane (101!) to keep from detonating.

This is probably not the way to go. It turns out to be more efficient to raise the boost level to get the power you want; and, in turn, lower the compression to keep away from detonation. You could always have an overdrive pulley custom fabricated, and JR might be willing to port their SC for more efficiency. One drawback of the SC is that the efficiency island is fairly small; at a certain speed, it stops pumping more air and just generates heat. You just can not push 15psi with the JRSC.

Note: if you do want to run close to the ragged edge of detonation, there are products to help you keep your engine from blowing such as the J&S safeguard: http://www.safeguard.20m.com/ But it's a touchy business, and I wouldn't recommend that strategy for a street car.

[Riceburner91]

Thanks fritz!! Thats exactly what I wanted to know and all in a way thats technical. Okay...then this poses another question. I'm sure you are aware of the service that Endyn will perform on a JRSC that puts it to making 12 psi I think...What kind of outcome could I see in 12 psi on the JRSC with all the other goodies of p&p with port matching and a built top and bottom end.....versus a good turbo setup with maybe 10-12 psi. I really like the idea of a supercharger but I'm starting to lean towards a turbo..considering it would be quite a bit more efficient and not have near as much loss when shifting since I have an auto. I'm trying to gather as much info as possible and also to give Level 10 when sending them my torque convertor and what stall speed to be set.

[Someguy]

Hey Fritz, that's probably worth looking into for my application down the road... Handling fuel cylinder to cylinder would be nice too... Thanks for posting it.

Anyway, in addition to what fritz mentioned opening the exhaust will give good gains with a supercharger. Header, cat, exhaust. You want to use a larger tube and exhaust then you would NA.

Openning the pre-supercharger intake helps lower charge tempatures and allows for a little more boost. Although its my understanding that the JSCs are pretty small as it is and aren't going to push that much more boost then 6-8 pounds anyway. In that case you will probably want to run about the same compression (but not higher) then stock even if you do rebuild the motor with stronger internals.

[Someguy]

You posted the same time I did.

Basically you will see more power with a turbo then a supercharger when running the same boost. A turbo will have something on the order of a couple percentage points of loss (to turn the compressor) and a supercharger will have much more then that. On the other hand the power curves will be shaped very differently.

A roots type blower reaches basically full boost very quickly after idle, while a turbo has to spool up. The larger the turbo, the more boost at lower charge tempature it can produce, but the slower it spools. The blower will feel like you have a bigger motor, since you effectively do; at any given RPM above just off idle the engine is ingesting a near fixed percentage more air, expelling the same percentage more exhaust and producing more power less the loss of turning the compressor. The turbo will hurt low end torque somewhat, but make up for it and surpass the blower on the top end.

[fritz_269]

What Someguy said.

And honestly, I don't believe that you (or Endyn) can reliably push the JRSC up to 12psi. That would be well over twice the rotation speed it was designed for. Imagine what kind of modifications it would take to get your prelude engine to spin at 15,000 rpm.

9psi, maybe. 12psi - be very careful.

The JRSC is very cool in a lot of ways, but a major drawback is that it's quite difficult to modify for more power (compared to a turbo kit). If you just want a plug-and-play solution for more power, the JRSC looks good. IMO, if you know that you'll want keep upgrading, you may want to look elsewhere.

The safeguard is a very cool little toy - I've heard great things about it. The only real trick is getting the knock sensor positioned correctly such that it really hears knocking and not valve clatter or suspension noise. From what I understand there's a fair amount of trial-and-error involved. But once you're set up right, you can't beat individual cylinder spark control!