but everytime you let off you lose your boost and get your lag back with a turbo.......it depends what you want it for. If your autocrossing, a SC may work better in a thight course since there are many corners and you can't afford to wait for a turbo. Most other types of racing, drag or high speed road course will prolly be best with a turbo. Like they say, there is more boost to be had with a turbo.

The biggest difference other than total boost pressure is how the boost behaves.

 

But if it is centrifugal, it brings lag back into the picture. Also, the vortech kits are much more time consuming to install than a turbo with lackluster gains.

 

Turbo a jdm lol what's the point. It's going to blow up anything over 8lbs of boost guaranteed. Turboing a high compression motor sounds like a pretty smart idea! Sleeve it then turbo and you won't have to worry. Plans for a supercharger are no different really. This prelude forum is the worst on the net, why I only post here about once every year. I laugh at some of the info passed on when it's not even correct to begin with!

 

Superchargers in general are a reliable source for boost, however, I'm not really a big fan of JR. In retrospect I should have went with a turbo instead of the JRSC kit, but I got the blower kit for a really good price at the time, so I went ahead with it.

The eaton blower itself is only good up to 10psi, after that, the high IATs will not make you any more power. Like somebody mentioned above, the JR kit does not allow you to run an intercooler, which is a really big factor, furthermore, the blower placement doesnt give you any room to run nitrous. Running the nitrous before the blower would damage the coating on the rotors, and there are clearance issues with running the shot between the blower and baseplate. There are also clearance issues with running a wet shot... so in short, it has not been done with the JRSC kit yet. There are similar problems with running water injection, it HAS been done before, but we're still unclear as to how it will interact with the coating on the rotors (really hot rotors + cold mist of water could cause something to break).

My main gripe is with JR's customer service. Back in the day when they were still in the minor leagues they had an awesome reputation. They would send out parts that wore out for free etc. I recently had a pulley melt on me due to debris from the ABS lines getting into the bearings (yes, the belts WILL cut into your ABS lines if you dont protect them... clearance problems again). At the end of the day I had 2 melted pullies and I was stuck at work. The techs at JR (specifically keith) were talking to me like I was an idiot, and refused to send me new pullies at their cost or even giving me the specs for them so i can get them for MUCH cheaper at NAPA. Keep in mind that they USED to have great customer support, and something like a pulley wouldnt really "set them back" or anything like that. Anyways... enough of the rant...

In short... JR kits:
You're stuck with JR, you cant get parts for the blower anywhere else
You cannot swap out the blower for a different size, all repairs/replacements must be through Eaton/JR
The EMS is a piece of CRAP, basically a bandaid system (some call it a piggyback)
No intercooler
No boosting over 10Psi (keeping in mind you'll have to change the fuel system and EMS.. a good $1200)
Cannot support nitrous
Will not make over 270whp EVER

A properly sized turbo will not have any noticible boost lag, however the torque does not come on instantly. A JRSC lude will have about 180lbft tq at 3k RPM and remain constant, a turbo lude will be stock at 3k rpm, but might have a higher peak tq. Take a look at the dyno's i got my hands on, both at 6 psi:

Turbo setup:............................................ ...............SC setup:

(dyno's taken from a dyno library at www.preludeonline.com, PM me if you want them taken down)
take note that at 6psi, the parasitic drag from the SC is neglegible in the dynos. Granted with much larger blowers (the M62 is a REALLY small blower) the parasitic loss would be a big factor. What I wanted everyone to see is that at 3k RPM the turbo at 6psi (not spooled) was making 70ft-lb, while the JRSC was making ~150ft-lb

Keep in mind, with a turbo you can always resize and get a larger one, with the JRSC, you're stuck with the M62. There is also a problem with vibration in the JRSC kit (specifically for the prelude), however JR is not willing to admit there is this problem... i experience a lot of audible vibration between 3.5k-5k, on the otherhand, turbo's have boost creep....

Hope this was helpful to some of you....

 

Do I sense sarcasm? If so, then it's a good thing you only post here once a year. Turboing a high compression engine is, in fact, a great idea. A higher compression ratio + x amount of boost, will ALWAYS make more power than a lower compression ratio with the same amount of boost. Will more reinforcement work need to be done? Yes, since the possibility of detonation rises along with the compression ratio. If you think I'm an idiot, then you're wrong. Go to www.preludepower.com and search for a post called "Raise Compression with Turbo". It's been proven. So before you run your mouth off about people not knowing what they are talking about, why you don't you get your facts straight. You're wrong, plain and simple.


Matt

 

I couldn't have said it better myself. Higher compression with turbo will always yield better HP than lower compression assuming tuning is very conservative.

 

I just got done building a 7000 dollar motor on my 99 sh I think I know what I'm doing. Don't believe me go to superhonda.com. Block was sleeved and built by Golden Eagle. Full stage 2 port and polish with full crower valvetrain and cams. I'm running Je 11.5 to 1 forged pistons and forged eagle rods. I'd never myself turbo a high compression motor just for the simple fact that your boost levels must remain low because of detonation. Your telling me you could easily put 25 to 30 psi of boost on that kind of compression you my friend are an idiot! Don't tell me I don't know what I'm doing. Golden Eagle warranties their blocks to 60 psi on sleeve cracking and sinking for 1 year. I'd guarantee if I put 25 psi to anything over 11 to 1 compression it's blowing up no matter what engine management you've got.

 

But saying that it is guaranteed to blow up over 8 psi is just ignorant. I have an open deck and run 8 psi daily driven with shitty engine management and 10:1 CR and I have yet to detonate or even come close to blowing my motor. A closed deck Prelude's only fault is the ring lands. If you can get a conservative tune, a higher compression motor that is built will handle 20 psi as long as detonation is nonexistent and it will beat the shit out of a 8.5:1 running 30 psi.

 

Actually, no, that's not what I said. I said you would have to do more reinforcement work to handle the higher compression ratio. Yes, the chance of detonation does increase, which is why you must build the engine correct. You seem to be missing the point of my post though. I agreed that blowing the motor is more likely to happen (if not properly built), I was saying that turboing a JDM is a great idea because higher compression will ALWAYS yield more power than a lower compression engine. I run 30 pounds of boost on my MR2 with 11:1 compression and it's going strong.. no signs of slowing down. Go ahead and put 30 pounds into a lower compression engine of the same type, and I'll run him all day long.


Matt

 

And for the record, you must not know too much of what you're doing if you had to have a shop do the entire build for you.


Matt