I'm just following TNTUBA around posting on anything he's been posting on, since we have similar SSM goals in mind. Also, I'm completely unable to leave a thread alone with people crapping on superchargers. It's a personality fault of mine.

This is my twin-screw supercharged power curve:
https://www.miataturbo.net/attachmen...ine=1341269331

It's about as flat as you can get, and makes it much easier to drive since it's predictable, linear power all the way through the curve, and it modulates with the throttle pedal in a predictable, linear fashion.

A turbo will never do that. Turbos are great for the track where you're just modulating mid corner and then flooring it on exit from a high RPM, but when you need to constantly go on/off gas and get the most power you can (i.e. autocross,) a twin screw supercharger is unbeatable.

A normal (M/MP) roots is okay, but tends to fall flatter on its face at higher boost at higher RPMs. For low boost they're fine. A centrifugal is all the worst parts of a turbo (power lag), without any of the advantage (laggy but still AVAILABLE torque at low RPMs) and is only useful for a track car with a VERY close ratio gearbox to keep it up in the boost. In that circumstance I'd still choose a turbo over a centrifugal SC since you can get so much more maximum power without parasiting it all away. Centrifugal is mostly just cheap and easier to plumb since it's small and can drop in a spot that has an A/C compressor or power steering pump...

https://www.miataturbo.net/attachmen...mathjtdall-jpg

All out turbo motor for comparison. Same dyno! got to be ready for the wall of torque that hits at 4000 rpm and a tiny bit of response lag mostly at lower rpm's.

owned:laugh:

And which one of these cars was faster this weekend?

What is done to the twin screw setup? How much money invested? Lets start there.

your "friend" likes to post dyno plots with no parts list or setup, then say something crummy about turbos and disappear

Can you read? He has a link to his build in his signature?

I got my ass handed to me. But we put miatas on top of the fleet of vetts vipers and RX7's.

I think Race logic traction control, Quafe Transmission so you can go fast enough in second gear, and a better rear wing were an advantage for David. I also think I got some suspension setup issues. maybe half of the differance could be chocked up to that. The other half he just out drove me.

Another thing was it was Goodyear vs Hoosier but I dont know what the differance there is.

Bob

Good job putting the Miata's on top. Now we all have to work to do it when the "real" RX7's are there.

signatures turned off:facepalm:
thanks for being a devensive a$$hole tho:giggle:

I'll check it out.
(PS: I do think his plot is impressive, don't get your panties twisted)

I try :) .........Anytime

You can't get your panties twisted........if you don't wear any :)

Bob: Are you running a 6spd? The quaife set really is perfect for autox... I think autotech has 2 kits left -- you should pick one up, especially if you're talking about building an XP miata.

BTW, We should spend some time Friday figuring out how to tune our wings. I bought a giant spool of pink twine from harbor freight for the purpose. :D

The goodyear vs hoosier thing is really interesting, and I think a lot of it comes down to driving style. I wish there was a good way to get really good data on the two tires, but the setup changes for the two tires on an SSM car to optimize them differently are huge...

But I don't have a dog in this fight. I don't think I would have anything for either one of you. My Co Driver might....but I have no skillz.

FWIW Scott Frasier still kicked both our asses running in CSP also in the same run group.

Bob

Scott is a machine. I was texting him Saturday night asking him if he just ever got tired of winning.

Total expense list for the build: Expense Log - DestinationSSM
Powertrain details for the build: Engine - DestinationSSM

Motor: Around 4500$ all done, half of which was the machine shop labor charge. In the end, I still think I overbuilt it, but I'd probably do about the same thing again if I had to start over. I'd spend a little more money on it if I were going turbo (stronger rods probably,) but it's a very very similar build to a high power turbo build.

Supercharger head unit: 2000$
SC crank pulley from FFS: 150$
Manifold from Corky: 860$ + infinite headache
Intercooler: 80$ + maybe 100$ of fab time
Intercooler piping: 100$ + maybe 100$ of fab time
RB header: 425$
Custom 3" stainless exhaust: ~1500$
AEM: 950$

In the end, the motor build, exhaust, and AEM are identical to what I'd do/have to pay for on a higher end turbo build. So, the SC "kit" is around 3000-3500$, depending on how much you can do yourself and how much you have to pay a welder to do.

Still got the 6 speed 3.636. 7400 rpm rev limit tops out at 60.3 mph in second. I kept blowing sound on sunday bouncing off the rev limiter past sound station. Just wasnt quite enough I think to warrent 3rd though.

Bob

Just looked over some of your site. Pretty sweet actually. Why can't more SC guys be like this. If there were more people like you and TNTUBA here maybe, just MAYBE we wouldn't hate on the sc guys so much:D

Yeah, sunday. I got him by quite a bit saturday. I left multiple seconds on the course sunday, which I fully admitted all run group sunday, and my PAX paid for it. :)

I think the courses were terrible for any cross class comparison, though. There were very few sections to use any power. I think our cars were basically overweight CSP cars for most of this weekend, especially on Sunday. I was just happy to stay ahead of Scott overall by 3 tenths for the weekend. :)

Awwww that's the sweetest thing anyone has said about me in years :)

Not all us blower guys are douches. I will freely admit I'm a jack ass....but not a douche.

David's car is breaking my heart. I had been thinking all winter I was going to have a bad Autocross Miata......and he had to come along a take it up a few notches.