JR supercharger as a "beauty mod"

J

JustinR32

New member
Yes, I wanted the power, but also I always thought that it is as much the look under the hood that I was always after. See what you think. I still have some hose- and wire routing and looming to clean up, btw.



Before:



3620dscf0116-med.jpg






After:



3620dscf0136-med.jpg








Tom
 
WOW Holy boost! Man that should give you a good kick!



Nice work and attention to detail, as if that wasn't a factor.



Good luck with this sick unit!



Regards,

Deanski
 
this may be a dumb question but....did you put anything between the exahust pipes and the supercharger(heat shield, wrapping, etc.). As in the pictures it seems it is mounted directly above them.
 
Ben,



Yeah, stock clutch. There's a little slip under full throttle shifting, but since I never shift under full throttle anyhow, it's no big deal. And yeah, smaller pulley. The stock kit is 5 to 6 psi, I'm about 7, maybe almost 8; the line to my gauge is long with a slight kink. I'm going to sort it out this weekend.



Calestus,



The header is ceramic-lined, but I know where you're coming from. The lower SC mounting bracket uses the upper header bolts. It isn't shielded, but it isn't an issue, either. I honestly couldn't tell you why it's not an issue, but there are several thousand JRSCs out there, and they're all mounted the same way (except for the cold-side conversions, of which there are less than 50, I'd bet), and it's not a problem. And, interestingly along the same lines, dyno tests on the stock JRSC show that an intercooler decreases hp. Again, I don't know why. I read the thread about it, and ignored the "why" but took the information I needed (which was, don't buy an intercooler).





Tom
 
superchargers arent all that efficient to begin with......neither are most intercoolers....they will drop the psi any where from .1 to 5 psi (some even more) depending on just how badly they are designed. but on the flip side a very efficient intercoller will drop your intake temperatures which means you can squirt just a wee bit more fuel in there mmmmm forced induction. as in everything there are gives and they are takes



i would give up 1 psi knowing i could squirt enough fuel in there to more than make up for the drop in psi even then i like cooler air flowing into my cylinders anyway.
 
Yeah, I should have said what I meant, "don't buy an intercooler for this particular application." I think that it doesn't cool enough, in this application, to make up for the loss in psi. And, it's like 900 bucks.



Tom
 
Mosca,



If you ever decide you want more boost (and you will :D), but intake charge temps temps and/or detonation become an issue, check into water injection . . .



Tort
 
BE VERY CAREFUL in coolish/cold weather. Blown engines will detonate in a heartbeat and you could loose rod(s) and/or get block ventilation. Back off some timing advance, make sure you are running really rich, run 93 octane or better to help control detonation. DYNO TUNE, DYNO TUNE, DYNO TUNE.



BTW the pix don't show up
 
Gonzo said:
BE VERY CAREFUL in coolish/cold weather. Blown engines will detonate in a heartbeat and you could loose rod(s) and/or get block ventilation. Back off some timing advance, make sure you are running really rich, run 93 octane or better to help control detonation. DYNO TUNE, DYNO TUNE, DYNO TUNE.



BTW the pix don't show up
Click to expand...

:xyxthumbs
 
Yeah, I didn't think the thread would have legs this long; the pics were in my Autopia gallery, and the spce there is limited. I'll repost them to cardomain & re-link.



The JRSC is really mild for a Miata; the engine can handle up to 250 rwhp before needing strengthened internals, and I'm at maybe 165. And, there isn't any tuning to do, really. You set the timing, then set the ACU to back out timing to 8* at full retard, and that's it. If the base timing is 12*, you set the ACU to pull 4*. If you set the base at 14*, set the ACU to pull 6*. I have mine set at 12* to pull 5* at full retard, to cure a mild knock at 7200rpm (redline). And I only use 93 or 94 octane.



The only other adjustment is to start pulling timing at 2500, 3000, or 3500 rpm. The Miata ECU isn't chippable. Attempts at i/e cam timing usually wind up with worse results. It's really by all accounts a turnkey operation on a turnkey car.



Miata performance mods are some of the most heavily researched and documented out there, every bit as much as Hondas and 5.0 Mustangs. for more info, anyone interested can check out



the Miata Forum Power Section





Tom
 
I've read your recent replies on miata.net and the brp forum. I too have recently installed JRSC on my 95' Miata. I have the same set up you do. 62.5 pulley, Bipes ACU and JR header. No heat shield for me either. I've heard lots of people bash the unit and complain how it doesn't compare to turbos, but I've been nothing but happy with my unit. The way I see it is before the install my car was faster than 65% of cars on the road. Now its faster than 90%. That's good enough for me. Nice car! Did you ever get that intercooler that guy was selling you?
 
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