Underdriving

[Greg@GLD]

Call me a wuss, but... I decided to take this blower install in baby steps and will underdrive the blower to begin with. I ordered a 3.70 pulley direct from Vortech and it came today, so I hope to finish this thing tomorrow. Will be somewhere around 7-8 PSI to start out, and it will take less HP to drive the blower this way. If things stay together, I'll go with the 3.33 pulley (11-12 PSI) eventually.

Coming down to the wire now...

[Kirk]

Gotta learn to crawl before you walk.

Good plan to feel it out before going for broke.

[Greg@GLD]

If I have a problem I'm going to be broke allright!
Getting more "debate" info.. Been told if the motor's got too much compression it won't matter if I underdrive it or not, it will still rattle and melt down. But we'll never know if we don't try.. :D

[Nick 1]

Big Bang Theory Greg ?????? ...................... :eek: :thud: :eek:




Nick 1

[Greg@GLD]

I have some ideas I'm kind of keeping to myself. This could go either way Nico.
Never seen such conflicting info on a tech subject in all the years I have been into these fuelie Mustangs.

[1slo5.0]

Call me a wuss, but... I decided to take this blower install in baby steps and will underdrive the blower to begin with. I ordered a 3.70 pulley direct from Vortech and it came today, so I hope to finish this thing tomorrow. Will be somewhere around 7-8 PSI to start out, and it will take less HP to drive the blower this way. If things stay together, I'll go with the 3.33 pulley (11-12 PSI) eventually.

Coming down to the wire now...


Where did your nutsack go Greg? Come on, hit it hard right away. :thumbs_up

[Nick 1]

I have some ideas I'm kind of keeping to myself. This could go either way Nico.
Never seen such conflicting info on a tech subject in all the years I have been into these fuelie Mustangs.

Kind of strange no one definative answer. I'll tell ya one thing Greg, the NMRA guys run some compression with a blower to make the Awesome power that they do. A race tune with Good Fuel & I think you'll be ok, IMO.


Nick 1

[bobtodd]

Let me know if things work for you Greg. I need help too with the compression I've got:D

[Kirk]

And you do have current A/F data too.

[Greg@GLD]

To answer Darrell- Figure it this way- I'll get my feet wet first, if the water's warm I'll jump in the deep end.
Once upon a time, I had an awesome 306 with a Vortech and all I had to do was leave it alone and drive it. Instead, I had to try to keep up with a couple guys I've had friendly rivalries with. So what did I do? I stuck a smaller pulley on the blower and for about a week the car ran like it had a 200 shot on it. Was keeping up with crotch rockets. Never got to the track with the smaller pulley and the pegged boost guage though- split the 306 across the entire deck and back down the rear while playing on Good Hope Road.
So much for big balls... They still hurt when you get kicked right square in the nutsack... ;)

[Yelooooh98GT]

I guess we'll be getting an answer on the debate eventually here.....

Nothing like tried and true real-world testing eh Greg? :)

[Greg@GLD]

And you do have current A/F data too.

The data from Saturday will mean NOTHING when boost is in the mix though... Have to start all over again, back on the dyno. Might take a roadtrip over to Paul's High Performance and dyno it there...

[NitrousEdge]

Sponsorship!

I'll definetly need spots and the hit!

[NitrousEdge]

I'll race you heads up Dan!

[Mark302]

At least you will have it on. That is the most important thing.

[Greg@GLD]

Mark, how did you run your PD? Underdriven? Were you really only running 5 PSI or was that an inside joke??

[NO CHANCE]

Greg,

Call ASSC Racing here in IL. I know for a fact that they've experimented with high boost/high compression combinations in the Pro 5.0 ranks of the NMRA. I've heard some discussion coming from their program relative to increasing compression, and underdriving blowers, as a method to make more horsepower, and increase engine/component durability.

http://www.asscracing.com/

[1slo5.0]

To answer Darrell- Figure it this way- I'll get my feet wet first, if the water's warm I'll jump in the deep end.
Once upon a time, I had an awesome 306 with a Vortech and all I had to do was leave it alone and drive it. Instead, I had to try to keep up with a couple guys I've had friendly rivalries with. So what did I do? I stuck a smaller pulley on the blower and for about a week the car ran like it had a 200 shot on it. Was keeping up with crotch rockets. Never got to the track with the smaller pulley and the pegged boost guage though- split the 306 across the entire deck and back down the rear while playing on Good Hope Road.
So much for big balls... They still hurt when you get kicked right square in the nutsack... ;)


I'm just messin' with ya buddy. :p

[Greg@GLD]

Jimmy Summers used to be involved with them and he used to test at GLD quite often.. Dangit! He works for Procharger now, so he does not come to GLD anymore (moved to Kansas I think?)
Keep in mind, this is a STREET car Jer, not an NMRA car that gets torn down after every race... It seems though I am getting good info as to underdriving it, and Paul Svinicki and Rick Anderson both suggested I try that if I am so paranoid. So I will. :D

Thanks for the info jerry> :BEER:

[Greg@GLD]

I'm just messin' with ya buddy. :p

Oh I know you are Darrell mah brotha! But I let the messin' get inside my head in the past, know what I'm sayin'?

Should be able to ship that PP tomorrow or Thursday BTW...

[Tom]

Does the EEC IV system have knock sensor capability? That's how the Buick boys were able to wring so much power out of 3.8 liters. Tuning by using the knock sensor. Maybe use an aftermarket unit. I know they're available.
Plus it would be another cool toy to play with.

[1slo5.0]

Should be able to ship that PP tomorrow or Thursday BTW...

Cool, thanks again!

[Kool Rock Steady]

Greg I agree. I only have stock pulley on my car and won't change it until I get a Keith Craft shortblock with motorsport block. I make enough power now with 6 psi. Let us know what it makes on the dyno

[Greg@GLD]

Larry, thanks to Robkong (QTRMILE) I found out something I didn't know- that SQ's make more boost than S-trims do out of the box. This is one reason I am underdriving the SQ. Hopefully everything will work out. I've stepped down (boostwise) 2 pulley sizes from "stock", the powerpipe is like stepping back one size. Difference is that the increased CFM from the powerpipe will add HP without creating extra drag on the blower. Also less stress on the crank.

Man am I nervous... :thud:

[Kool Rock Steady]

why be nervous? If you are 500 or more then be nervous.

Jim Summers is at all the NMRA and WFC events I've been too. Go outside WI sometime greg.. :D