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Greg Gordon
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2.5 Supercharged dyno results

Post by Greg Gordon »

My 2.5 has been dynoed. It puts out an incredible 236 flywheel horsepower and 244 pounds of torque! It has 219 pounds of torque at 2400 rpm (for comparison a 3.0s PEAK torque is 181). These numbers are converted from rear wheel horsepower, I will put the raw data on my site and hopefully the dyno graph if I can figure out how.
The engine is TOTALY STOCK other then the supercharger kit. When I say STOCK that's what I mean. It has it's original AFM, injectors, manifolds, L-Jetronic, everything.
I did everything I could to make this a fair dyno run. It was done on a warm day, I used my worst flowing cone filter, not the good filter I include with the kit, 1/2 tank of fuel (more fuel in the tank=more power on a forced induction motor), stock ignition timing, 93 octane (r+m/2) PUMP gas with NO additives, and so on. We stopped at 6200 RPM since that's near the stock rev limiter.
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Post by Mats »

Sounds very nice... *drool*

If I calculated correctly that should be ~330Nm of torque? :)

Now, I'll start the usual stuff:

Charts!
Pics
Soundfiles/video!

;)
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Post by Greg Gordon »

Thanks Mats, I must confess I don't know what an Nm is. But I can tell you the torque number translates into a massive amount of acceleration, even more tire smoke and quite a few embarrased WRXs.
I am working on the chart, I want to put it on my site. I don't have a video camera. There is already a decent picture on my site.
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SydneyJules
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Post by SydneyJules »

NewtonMetres!

Mmmmmm! Plenty of em!

I wonder whether it will work as nicely with my cams and a comp drop!?!?

I must admit, this is really appealing as far as a street car is concerned!!!!

No need to stuff around with gearboxes other than what I already have in..... and the torque.....

I cant wait to see some vids, please, Greg!!!!
Fixing it bit by bit....
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Post by Greg Gordon »

Everyone keeps mentioning videos. I can barely work a digital camera and post pictures on my site.

However in the event that I can figure it out, just what is it you want a video of. My car looks absolutely dead stock with mostly original paint, original wheels, 205/60 P-6000s. Not much to see there. One burnout video looks much the same as another too me. Let me know and I will see what I can do.
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Post by Zamani »

What about getting the pulley with the highest boost, and then put in an electronic boost controller? THat way you can boost up on short runs.
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Post by SydneyJules »

Yeah but that way you're gonna get the hotter charge air of the higher boost setting, whether you bleed it off or not.... the best boost controller is your right foot! I woudn't ever bother with boost controllers.

I really must say, that my opinion of volumetric blowers has really changed in the last year!

I would never use a centrifugal for anything other than a high speed run car- and Greg, your Blower set up has me thinking about ways to get my 2.5's comp down on the cheap so I can start forcing air into it!

I'd love someone's opinion on the 3.0 pistons and liner swap, in terms of comp ratio achieved. I recall it being around 10:1, but less is better!

EXCEPT! With the crazy overlap and duration on my cams, I wonder whether I will be blowing all my boosted air out the exhaust, or whether the forced volume of air will increase my effective CR, as it's really a given volume, and not so much a compressed volume of air.

Barry, Kev, Mats, Z, Greg- anybody- opinions on that please!

Greg, you did say the 3.0 you fit it to was mildly warmed over with 10:1- what boost was he running? What octane?

What sort of Boost-per-CR-Point are you guessing with this setup? I recall a figure of 4 psi per compression point being nice....
Fixing it bit by bit....
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Post by Greg Gordon »

Zamani, you are a thinker, but this is just not a good idea brother. I actually thought about it. The problem is this, for a given amount of boost the power needed to drive the supercharger goes up with RPM. That is at say 5 pounds of boost the blower uses a lot more power at 14,000 rpm then it does at say 10,000. So if I was to use an electronically controlled valve to release pressure to keep boost down the supercharger would be spinning faster then it would be at the same boost level without this controlled leak idea and thus wasting energy. I hope I am making sense, I have had a really long day.

I have gone through a HUGE amount of trouble to set this thing up to be efficient. I don't even want to think about all the discharge ports I designed and made trying to reduce the needed blower RPM for desired boost levels (5-9 psi range on the 2.5 and 4-7 psi on the 3.0) while still fitting the thing under the stock hood. It's probably the most efficient remote mounted roots type blower kit out there.

Julian,
I have untested thicker headgaskets that reduce compression about 1 point. Untested means just that. I usually don't sell anything until I have put it on my own car and abused it some. I have not used these yet.
I can't answer your cam question, that's a little out of my area. But I don't think they would work well, if for no other reason then an incompatible RPM range. The supercharger kit is optimized for 6000-6500 rpm redline engines, that's how I designed it.
My honest thoughts are that your engine is so awsome I wouldn't change it. It would be a lot easier to use a whole different engine for supercharging.
The 3.0 you are refering to is Bill's SCCA Verde. It's 10:1 "S" pistons with "S" cams, IAP headers and a big AFM and my Stage 2 injectors. He runs pump 93 octane R+M/2 (see the bottom of page 7 on my site for more on this R+M/2 crap) a can of octane booster from the local auto parts store which adds a couple tenths of a point and an Aquamist Brand water injection system. We set his car up with 5.8 pounds of boost and it's putting out about 290 horsepower. Frankly I am a little uncomfortable with it...too much boost and compression for cast pistons. However he says it doesn't ping and I believe him.
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Post by SydneyJules »

Awesome? Shucks! :oops:

A blown forced induction setup seems my only way to get my car to the torque point I want. Then I could keep it as a streeter. And my girlfriend could drive it, and I could drink some nights! Haha
Yeah I'm not too keen on thicker headgaskets, as I believe that it simply creates two weaker spots in the seal, rather than one.

Then again, plenty go around with them for a long time, and never have problems, I just dont like it!

I think that at 10:1 with 98 octane (which is readily accessible here), I could get nearly 8psi into the motor. the RPM thing is a fair issue, though, because my cams probably make peak power @ around 7800-8000. Gilmer drives could be the go, :wink: then I would have some serious mechanicial cacophony going....

Maybe i gotta do this on my own!
Fixing it bit by bit....
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Post by Greg Gordon »

An 8000 rpm 2.5 will need an M90, the M62 just won't do it. Or...TWIN M45s! I have designs for both. I didn't actually design them for a high rpm 2.5 but rather for a higher boost 3.0, like around 12+ pounds, either way it's sort of the same problem, trying to keep supercharger rpm low while delivering the desired boost. By the way, for those not clear on this, those numbers are the cubic inch displacement for one revolution of the rotor group. (ie. M62 is 62 cubic inches).
The trouble is there is no transaxle that can handle 12 pounds of boost on a 3.0 so I doubt I will ever build one.
As long as I am drifting totally off topic here anyway, I think a lightened straight cut gear set would do the trick.
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Pistons

Post by Kunta »

Hi there Greg

I followed up your link that you sent me, but i am a little bit curious abut the pistons you used for the 3 litre block. Do you have any specs on those ones?
As i understood you can drive the M62 for 12 pound/inch sqare2 ( (0.8bar), is it possible do make about 1.0-1.1bar with ic setup? (14-16 pund/inch sqare2)

We want som more pictures!! :D :D :D :D
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Post by Greg Gordon »

Hi Kunta, I assume you are asking about my dad's 8.8:1 non interference pistons. They are flat tops specifically for supercharging with deep valve cut outs. The valve cut out has to be so deep that it gets into the ring grooves. So we slightly lowered the ring groves which puts the oil control ring into the wrist pin hole. So we use a teflon buttons to secure the wrist pin instead of the usual clip method. This is perfectly secure and will out last the factory set up. If you ever want a set I can give you the Venolia order number so they can make you the same thing in whatever bore size you want. We don't sell pistons anymore.
For 12 pounds of boost on a 3.0 you need an M90 which is no problem, I can make the kit with an M90 for just slightly more money.
As a general rule it's better to spin a small supercharger fast to get the desired boost then it is to spin a big supercharger slow. However that's only true up to a point.
If I didn't make this clear before I will try now. The M62 kit is designed to be efficient in the 5-9 psi range on the 2.5 and 4-7 psi on the 3.0. If you want much more then that the M62 has to spin so fast it's better to get an M90 and spin it slower.
Keep in mind 9 psi on a 2.5 will easily provide 270 horsepower on a well set up motor, ie. headers and stuff. On a 3.0, 7 psi will get it above 300 horsepower on a well set up motor. So in practial terms there is little need for the M90.
This may all seem a little confusing, but I do have it all worked out.
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Post by Kunta »

Greg Gordon wrote:Hi Kunta, I assume you are asking about my dad's 8.8:1 non interference pistons.

... If you ever want a set I can give you the Venolia order number so they can make you the same thing in whatever bore size you want.
...For 12 pounds of boost on a 3.0 you need an M90 which is no problem, I can make the kit with an M90 for just slightly more money.
Yes, exactly. I have emailed Venolia Usa a couple of days ago but have not returned any answer from them. The order number would be very interesting.

My engine projekt has damages to all pistons from the intake valves so i will probably swap them for new ones anyway. I saw the prices for your "do-it-yourself" kit, how much extra is we talkning about with the m90 unit instead?

Keep up the good work! 8)
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Post by Greg Gordon »

By the way, although all this supercharging stuff is exciting don't forget to check out the Incredible naturally aspirated motor on page 4 here: http://www.oldebottles.com/italiancarspage4.htm . Built by one of our customers over in Viking territory (real vikings, not the football team) That thing will probably be near 300 horsepower!
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Post by Greg Gordon »

Ouch, dang, that's one damaged piston!
I will dig that order number up and PM it to you. Venolia is bad about answering e mails, good at making pistons.
I have found it's best to call them.
The M90 is $200 more at this time. This is entirely because it costs $200 more.
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