Realistic fwhp number for Roots Supercharger

[shomethe$$$]

Searched and only found HP runs for the centrifugal guys, around 320 fwhp, i'm having a discussion on honda forums and most are saying i won't get more than 270-280 to the ground, my goal is 350 FWHP on 94 octane

Maintained stock 3.0L engine
1) M90 Roots off 94-95 SC,
-the more efficient one w/ teflon rotors and larger inlet
-16,000 rpm @6400, 2.5 ratio(best guess 13psi and 750 CFM)
-aluminum 8-rib drive pulley and gatorback belt w/ 25lb, auto-tensioner
-75mm throttle inlet
-turboxs or greddy dump valve

2) FMIC w/ 2.5" piping, 24X15X2.5

3) 2-1/8 downpipes to 3" single exhaust, magnaflow muffler

4)Dual rail fuel system, 6AN throughout, mallory FPR, 255 hp FP

5)Accel 48's with MarkVIII 80mm MAF, tuned with tweecer (later with WB)

I want to get a rough idea w/o going to the track or making a dyno run, the centrifugal guys know what they'll get, input please

[Geek SHO]

246 fwhp / 244 fwtq
We later found that the motor was running on 5 to 5 1/2 cylinders. It's a first generation M90 boosting 9psi.





Using the metal-box intake, there's no reasonable way to use a FMIC, though we did toss around ideas of a water-to-air intercooler. Just using a stock intake would probably yield a lot more power, but blower location would be less obvious. Having it stick out the hood is really cool. Also, throttle response is instantaneous. The boost gauge acts like a throttle gauge.

With all the stuff you propose, I firmly believe you could get well over your target of 350 fwhp. As for my project, I will be handing it back over to Tyler Garlock once I can find some space to work on the car and retrieve the parts, and once he stops fussing around with his 2004 Cobra and gets another SHO.

If I may make rash generalizations, Honda guys are retarded. Last time I was at the drags, a guy had a Civic with a monster boosted motor (600 fwhp) but was using stock axles combined with steam roller drag slicks. The axles broke on his second pass . . . DUH!

[yamahaSHO]

Originally Posted by shomethe$$$

Searched and only found HP runs for the centrifugal guys, around 320 fwhp,

What boost are we talking about because I have never been even remotely close to that low of a number with boost?

[somedude_001]

Originally Posted by Geek SHO

246 fwhp / 244 fwtq
We later found that the motor was running on 5 to 5 1/2 cylinders. It's a first generation M90 boosting 9psi.





Using the metal-box intake, there's no reasonable way to use a FMIC, though we did toss around ideas of a water-to-air intercooler. Just using a stock intake would probably yield a lot more power, but blower location would be less obvious. Having it stick out the hood is really cool. Also, throttle response is instantaneous. The boost gauge acts like a throttle gauge.

With all the stuff you propose, I firmly believe you could get well over your target of 350 fwhp. As for my project, I will be handing it back over to Tyler Garlock once I can find some space to work on the car and retrieve the parts, and once he stops fussing around with his 2004 Cobra and gets another SHO.

If I may make rash generalizations, Honda guys are retarded. Last time I was at the drags, a guy had a Civic with a monster boosted motor (600 fwhp) but was using stock axles combined with steam roller drag slicks. The axles broke on his second pass . . . DUH!

you might laugh about the honda guys running stock axles but their stock drivetrain is extremely strong. + that 600whp is not 600 ftlb of torque. probably mid 400ftlb would be my guess.

at 13psi I would guess 320-350whp with a S/C and high 300's low 400's with a turbo.

edit: I woudl love a SHO with a PD blowr like yours. that car will be downright violent.

[yamahaSHO]

The also don't have the same amount of weight to pull around.

If it were a more efficient supercharger, with 13 PSI I would say 400+ whp.

[Off Road SHO]

I would aggree with Jason on this one. BTW, are you using the M-90 off of the SuperCoupe for any particular reason? The M-90's off of the GM cars have the trottle body attached to the back and have an internal bypass that the Ford version doesn't have.

The M-112 off of the Cobras and Lightnings will give you boost sooner and larger volumes without having to spin it so high, which creates heat.

The Other Woman put 278 hp and 300 torque to the ground through her highly parasitic Mendeola Drive train. That was with a max of 8psi and running 39lb injectors. While she is turbo'd now and runs extremely well, I miss that low end grunt that I got from the blower and will be going back to the M-112 soon.

Tom

[cmz829]

Im not sure exactly what he is running but a local guy in pittsburgh has a SHO motor in a sable wagon with a m90 supercharger on it. if i remember right he had a little over 300whp. SV&HOdan may be able to tell you more about it as he knows about it better then i do.

http://www.youtube.com/watch?v=EpQGQ6kX5gU

[rubydist]

Originally Posted by shomethe$$$

Maintained stock 3.0L engine
1) M90 Roots off 94-95 SC,
-the more efficient one w/ teflon rotors and larger inlet
-16,000 rpm @6400, 2.5 ratio(best guess 13psi and 750 CFM)

I don't think you'll get 750 cfm out of the SuperCoupe M90. (BTW, I have a 94 S/C blower on my Ranger). According to their published data for the Gen 3 blowers, they flow 520 cfm at 12000 rpm and 10 psi. As I recall, 12500 is the rated limit for the blower, so 16k would really be pushing it. If it were to survive 16k rpm, it would move less than 700 cfm at 10 psi, and more like 650 or less at 13 psi. At some rpm, you will start having significant pressure drop across the inlet and the flow rate will stop increasing.

If it flows 650 at 16k rpm, that would probably be around 13 psi at 6400 engine rpm, according to my math. It would also desperately need charge cooling at those kinds of boost.

I agree that the M112 would be a better choice, and a Kenne Bell or a Whipple would be better yet. Whenever I've looked at it, my math says the M90 is really too small to put serious boost into the SHO motor, if you want to let it run to redline.

[somedude_001]

Whenever I've looked at it, my math says the M90 is really too small to put serious boost into the SHO motor, if you want to let it run to redline.

you could be baller and run 2

[bubba]

I would go with the M-112 myself. Do it right the first time. And get a 100 shot

[Brett]

Originally Posted by rubydist

I don't think you'll get 750 cfm out of the SuperCoupe M90. (BTW, I have a 94 S/C blower on my Ranger). According to their published data for the Gen 3 blowers, they flow 520 cfm at 12000 rpm and 10 psi. As I recall, 12500 is the rated limit for the blower, so 16k would really be pushing it. If it were to survive 16k rpm, it would move less than 700 cfm at 10 psi, and more like 650 or less at 13 psi. At some rpm, you will start having significant pressure drop across the inlet and the flow rate will stop increasing.

If it flows 650 at 16k rpm, that would probably be around 13 psi at 6400 engine rpm, according to my math. It would also desperately need charge cooling at those kinds of boost.

I agree that the M112 would be a better choice, and a Kenne Bell or a Whipple would be better yet. Whenever I've looked at it, my math says the M90 is really too small to put serious boost into the SHO motor, if you want to let it run to redline.

Id imagine using the SC off of the thunderbird SC is probably more for budget then performance, most people know they aren't the greatest/ flowing units, m90's can be had for so cheap its hard not to click buy it now.

[rubydist]

At the moment, on ebay there are a couple of S/C M90s for less than $200, and a couple of M112s (one Cobra, one Lightning) for under $250. If you pick up a 14 year old M90, you can pretty well plan to spend at least $50 to put in a new coupler, new snout seal, and new oil. The M112s also have the integrated bypass valve, so that saves another $50 plus. So, you could build a case that the M112 would cost less to put into service. Now, if you want a Whipple, then you need to add a zero...

[Geek SHO]

It runs off the serpentine system. It's just a much longer belt than normal with no added pullies. The blower was bought from a junkyard for about $50, has a gajillion miles on it, and it shows. It slowly leaks gear oil. I see Super Coupes at the junkyard all the time, half of them with their blowers missing. I never see any newer than '92 or so, which I know has the much less desireable first generation M90. I don't know what year they switched.

Even if a Civic is making *only* 400 lbs of torque, that's what, four times as much as the factory motor? Still seems stupid to leave the axles as the obvious weak point of the drivetrain.

[NoSHOAllGo]

GeekSHO, did you rebuild the engine yet and run a new dyno?

Im curious to see what #s you would get.

[Geek SHO]

The car has not been worked on for a year and a half now. I just don't have the space to tear a car apart for more than a week. Once I get to working on the car, I will be returning the blower parts to Tyler, who graciously lent them to me for an unspecified time. Once I get a healthy running motor, I will be preparing for a turbo.

I suspect that if it was a healthy motor (and with crankcase vent problems solved, etc) and a rebuilt Gen II M90, it could make closer to 300 fwhp.

I don't want to hijack the thread, so PM me if you have more questions about my car.

[shomethe$$$]

Originally Posted by yamahaSHO

What boost are we talking about because I have never been even remotely close to that low of a number with boost?

Its a conservative number, very conservative thats why I'm looking for a realistic number with the roots


the 75 mm throttle is before the inlet like the other guys, a 94-95 SC is hard to find, there are only a dozen or so around, the SC guys don't sell them unless the inlet is tore up, they are running 12's in the t-bird with 18psi overdrive up to 15-20%, I think my goal is attainable with the Gen II M90

i'll upgrade to a M112 but budget is an issue right now but it won't come off a Ford Lightning or Stang but most likely a Jaquar or Rover


Remember guys, its going in my Honda Prelude, I'll revive my thread in sho related

[yamahaSHO]

Asked because you said you found dyno runs for the centrifugal guys and I don't know of many below 400whp.

I think the better option, especially if it's going in a Prelude, would be to make a cheap turbo kit. It'll be plenty fast and should be reliable if built right. You can also easily tailor boost after wards to meet your needs. 300whp all the way to 450+whp will be attainable.

[twr]

Looking through the dyno archive, I saw only 1 centrifugal that was below 320whp and it has/had a very bad tune at the time. Hell mine with 8/9psi of boost and a quessed tune was at 355whp, but with adding a little timing it was up to 370hp. But I'm not over 400whp just yet - did 390whp earlier this month.

I think 320whp is extremely conservative number. IMO, 350 is a conservative number.

[somedude_001]

Originally Posted by Geek SHO

Even if a Civic is making *only* 400 lbs of torque, that's what, four times as much as the factory motor? Still seems stupid to leave the axles as the obvious weak point of the drivetrain.

maybe he has the same mentality as a bunch of the SHO guys. it is either axles or the transmission

[twr]

Originally Posted by somedude_001

maybe he has the same mentality as a bunch of the SHO guys. it is either axles or the transmission

Yeah, I'd rather break an axle (and have) rather than the transmission.

[rubydist]

Originally Posted by Geek SHO

I never see any newer than '92 or so, which I know has the much less desireable first generation M90. I don't know what year they switched.

89-93 had the oval inlet, 94-95 had the rectangular inlet and coated rotors. The 94-95 blower is enough more efficient that Ford changed the blower pulley from 3.135 to 3.275 and it still made the same boost.