Rotary_Rocket_87

If you are running faster than T2s and RX8s, then why was that Sport you were racing pulling away from you in the long straits? It looks like you were just the better driver in a car that had enough power to keep up.

trainwreck517

iTrader: (1)

His motor was ported, with less then 5k on it.
full strait pipe exhuast.
intake.
SAFCII.
And he didn't pull on me in the straits.
I let him pass me on the straits so I could chase him down, point by rule apply's at the track.
I then give him some space coming out of turn one to make it fun to reel him in.
He also had 235's racing slicks, when I only had 205's street tires, so I had to take it slower in the turns.
I was only running 6psi, and STOCK exhaust... and tuned at 10.5-10.8 which is pretty rich.

The car was faster then a stock rx-8. I did a simlar run with my friends 05 Rx-8.. battery died so didn't record it, but after turn 1.. he couldn't get rid of me.. and then I had him chase me.. after turn two, "cotton corners", I was long gone. and he couldn't catch up to me after words.. by the time I hit sun set, he was bearly going into the esses.. I realy wish I would have the footage.. but if you'd like I can ask him to post here on what he thought of the car.


And thanks for the comment about being a better driver, makes me feel better.

But for people thinking of SC.. don't expect to make crazy power. But it sure is fun to have that instant throttle responce.

And I'm sure the car would be alot more fun if I had a full exhaust though, that stock exhuast is just choking it down.

evelhalo

not that were on the original question but im still tryin to figure this out, keep in mind tho when im doin MY math, the t2 starts at like 2000-2500 after install if i do it myself, then i would need to upgrade things and possibly get a new tranny/rear end.
I have a stock port n/a in good condition, which i am porting here in the near future, for free,
so if i make it to 220-250rwhp then i may also need to replace my diff
so i think the supercharger may be a better, mor cost effective way to go......

....... anyone know of any superchargers you could fab on? maybey not specific ones, but size, brand, any other cheaper setup i could pick up that would just require some fabrication??

ErixHvn

I'm in the process of fabbing my Millenia twin screw SC on my 86 sport. There are some issues I still have to contend with at the moment but will soon be finalizing the actual install. Will be posting about it as soon as I start the build.
Meantime if you're interested check this out then. https://www.rx7club.com/forum/showthread.php?t=527282 [url]

Stick around, It might be a pleasant surprise using this particular blower as it may yield higher Hp/torque than a Camden. I'm trying to keep this build as close to bolt on as possible and finding the right sources for machining and welding the parts has been the hardest obstacle yet. Maybe there might be other NA owners who might be interested in a kit after I'm done with it. If I didn't have to spend so much money on the R&D of my project, I'd buy Trainwreck's ride just to have a different SC'd Rex to compare to.

The Camden kit has been maligned for it HP/$ cost. Howevere most of those that knock it have never even been in a supercharged RX. Mostly it's out of fear of the unknown. The turbo community does have a lot more support because of the turbo setups having been tried and tested over time. But consider the fact that the supercharger properly sized and tuned is a much more predictable beast to drive as a DD or even on the track. The throttle response quicker and more torque on the low-midend. Which is partly the reason why I chose to SC rather than turbo for my project. Trainwreck gets my kudos for going this route. The road less travelled may not always be smooth but the ride might just be that much more fun. Right Trainwreck?

adrock3217

J-spec with tranny, shipped to your door, $900. Osaka.

And who would spend $800 on a stock T2 exhaust? Your dreaming, buddy.

I stand by my post, except the SAFC2 pricing.

T2 > Supercharger. More potential for higher horsepower, more potential for less spending.

adrock3217

Consider the fact that a properly sized single-turbo, with a wastegate that can flow enough, will be just as much of a predictable beast to drive as a DD or even the track, and will give you smiles at the top-end rather then just the low and mid-end. The throttle response on any supercharger that can provide significant gains will spool much like a turbo, but still choke at the top-end. Good luck with that.

trainwreck517

iTrader: (1)

$900 for a jspec with tranny? Better come with some kinda warrenty, because at that price seems like your buying a paperweight, might not even be a good core to rebuild.
Do forget you will also need a uncut harness and ECU.. sure its not encluded in that price.

You sitll have to pay over $1500 to rebuild it.. 2.5k+ if you go with new housings.

$800 was for a turbo back.

And yes the T2 has more power potential, and would be cheaper for higher power. I have established that.

trainwreck517

iTrader: (1)

What do you mean by "choke at the top-end"?
Durring the track event, I took my car up to 9k.. and it pulled ALOT harder at 9k then it did at 8K or 7k.. ... it just wanted MORE.. main reason why I would shift early.. don't trust my flywheel at those high rpms for to long.. don't want to lose my legs.

And I don't know about being predicable on a turbo setup.. on my FD.. it gets pretty tricky when secondary kicks in, or when the boost just comes in out of nowhere.

Same thing goes for my rx-2 with a single turbo, .86 hot side 60-1 compressor... Its goes from 0psi to 14psi in about second.. and really hard to controll the boost with your foot when coming out of a corner.. and 1/4 I can stil build about 10psi of boost.. and thats more then enough to make it get *** happy.

With the superchager at 1/4 only seeing about 1psi of boost.. and that will never change and catch me off guard.

ErixHvn

Quoting Adrock (I like your avatar BTW)
"Consider the fact that a properly sized single-turbo, with a wastegate that can flow enough, will be just as much of a predictable beast to drive as a DD or even the track, and will give you smiles at the top-end rather then just the low and mid-end. The throttle response on any supercharger that can provide significant gains will spool much like a turbo, but still choke at the top-end. Good luck with that."

That's the reason I'm going w/ the Twin screw Millenia lysholm SC, Should I decide to go above the initially designed for boost pressure of about 8lbs my SC will blow all the way up to 14-15 lbs. with the right pulley. Don't think it'll choke there. Just instant boost that comes on and stays on. No lag or creep. The low end driveability of an SC'd NA would also be an advantage in the curves whereas a turbo would have to downshift to keep the revs/boost up IMHO. Thus higher exit speeds like Trainwreck is experiencing.

It's hard to compare performance if all that's considered is top end. Apples to apples it's not. The turbo and SC's characteristics are similar but there exists a difference in where peak torque is achieved and maintained on the powerband, At least that's what I believe. And I do believe that the SC's wider torque curve would be more suited to my style of driving. But then again, I could be wrong.......
We'll just have to wait and see when I get mine together. Damn AC lines getting in the way at the firewall is what's slowing this project down the most.

Twofer

Every time a S/C thread comes up, I wonder why noone has tried an intercooled centrifugal supercharger like a ATI Procharger, Paxton or Vortech.

I know a fellow who races Porsche 924/944's (the competition to our cars) who helped a friend with a Procharger setup w/out intercooler and said it was a pain. Had to fab all the mounts and never got it to idle right. He seemed like a pretty knowledgable guy but no professional tuner. Also I don't think he did any fuel system or fuel computer work.

Jager

iTrader: (10)

Because of the companies that you listed, only Paxton has made a kit for the FC and they only sold like 10 of them.

Unseen24-7

I have had an idea for an intercooled supercharger setup. See pic.

Unseen24-7

yeah i know it's an old thread, but i didn't feel like starting a new one ^^^^. The supercharger replaces the A/C compresser, if you were confused.

importsown

Yea thats what i always wondered. Even if they dont have "kits" how hard would it be to fab up a bracket and pulley system to turn a properly sized centrifugal?? Replacing the A/C with a supercharger seems like a decent idea to me. Space may be the big thing here.

rarson

Unseen: Looks good, but I think you'll find that you will need an idler pulley. It would go underneath the bottom part of the SC belt, in order to give more wrap around the SC pulley. Superchargers are notorious for belt slippage and I think you'd eventually find that another pulley would be necessary to add grip while preventing belt snappage.

Here's a big disclaimer though, I'm not a supercharger guy and I don't have experience with them. But I've heard enough about belt problems to know a little about fixing and anticipating them. I just think it's a no brainer that you will need more belt contact through an idler pulley.

ramses666

iTrader: (1)

Put a whipple on it, & add a aftercooler as well. Linear curve for torque & HP for a twin-screw vs. somekind of blow-off valve dependant turbo limit on the same motor would appear to be worthwhile. This would be only a guess & an expensive one for sure... but we are not talking about $$$$$$. I guess we won't know until someone does one. How about a 20B? Now that would be worth talking about!!

Ramses666

trainwreck517

iTrader: (1)

Some one on this forum did just that, using a twin screw from a melluinum(sp?).

He also had the TB infront of the SC.. he was running a megasquirt ecu.. so no afm.

ErixHvn

That was 88intergraLS's setup but it never really got tuned before he gave it up for a V8 transplant. Had good potential but never really got to the full realization of the project. That's why I'm doing mine. Also w/ a Millenia twin screw and intercooler. It's still on standby right now due to other more important obligations, However, As soon as I get the time this will be the next goal.

Roen

iTrader: (2)

Regarding the screw-type superchargers, I always thought Kenne-Bell made better chargers than Whipple. Does anyone have any information around this?

rarson

I thought this was already covered in this thread: KB superchargers are Whipple.

raptor22

OR...how bout this? Go "class A rally style" and have a clutched supercharger that runs on the low end...and cuts out after a it spools a huge turbo?

Fast throttle response AND huge power.

Sideways7

iTrader: (7)

I've always wondered why no one's tried that setup, too. I know I've seen some Ferrari tuner super-turbo-charge a testarossa. Of course if it ends up anything like a rally car(especially the focus) it'll be crazy loud from all the popping and weird noises.

rarson

There's no need to cut the supercharger out. Just plumb the turbo into the supercharger.

See most people can't seem to grasp the concept of series pumps. The supercharger takes x amount of airflow at y psi and adds z psi to it. So having x amount of airflow at y*2 psi, it's still adding z psi on top of that. No "overrunning the supercharger", it's still flowing more air than the engine is (just at a greater psi).

raptor22

Heck, the turbo-super-charged setup isn't even allowed in rally anymore because it is too fast.

Class A similar to the class b rally that we are familiar with, but there were far less restrictions. it was eventually abolished because the cars were too fast for the drivers of the time to control and there were alot of deaths. I talked to a guy who owns and used to race a class a rally car...he used a massive airplane turbo with a clutched supercharger. I don't remember the horsepower figures, but he said the little 4-banger could do 0-60 in 2 seconds or some insane number like that.

Rarson: the whole point is that the turbo is more effecient at producing power, so it can be sized to produce full boost most effeciently while the supercharger can have a very high rpm pulley to produce best power at low end.

--Alex

88IntegraLS

Supercharged rotaries are ******* sweet when they have a real twin screw charger making the boost. I saw 8 psi with my millenia S setup on my large streetported 13B and the damn thing felt like it grew a third rotor! We're talking almost instant boost at LOW rpm, fmic and everything.

The only thing that could top a twin screw supercharged 13b would be a bigger twin screw charger feeding a 20b, or the real practical solution, NA V8, bwahahaha.