Not enough Vroom for SPA?

General chat that fellow COM'ers may be interested in.
offcamber09
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Not enough Vroom for SPA?

Post by offcamber09 » Tue Apr 01, 2008 9:22 pm

Ok this will come across as sandbagging- but I have the graph to prove it...

From this Sat. at Performance Dyno in Concord:

Peak HP= 318 rwhp @ 5200 rpm

Peak Torque= 360 lb/ft @ 4400 rpm

I'm really surprised by the hp #, especially the 5200 peak. The curve does not fall off dramatically by 6000 rpm, but my "butt-dyno" told me it was pulling higher than it is.

So my question to myself and anyone who wants to listen is..."this car is going to be quicker than the yellow car- but is it enough for SPA since the HP war is on (Hello Joel, Mario and James)"?

Joel is nice enough to advertise his HP and estimating his cars weight at around 3500# that would give him a weight to HP ratio of around 8.13.
My cars ratio is around 9.30.
I bet Mario and James' cars have ratios at or below 7.

Not to slight any other SPAers- I'm just working with the cars I'm most familiar with.

I don't see how you guys can lose to me... are you psyched out yet? 8)
Scott Rosnick
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Mick
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Post by Mick » Tue Apr 01, 2008 11:39 pm

I'm psyched out and I'm not even in SPA.
How are you calculating the numbers, off of wheel or estimated crank hp figures?

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Post by offcamber09 » Wed Apr 02, 2008 6:49 am

Mick wrote:I'm psyched out and I'm not even in SPA.
How are you calculating the numbers, off of wheel or estimated crank hp figures?
At the rear wheels. Pete at Performance dyno says 318 at the wheels equates to 430 at the crank. I thought that sounded like a lot of parasitic loss- I always thought 15-20% loss off bhp would give you wheel hp.
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Post by chaos4NH » Wed Apr 02, 2008 8:56 am

offcamber09 wrote:
Mick wrote:I'm psyched out and I'm not even in SPA.
How are you calculating the numbers, off of wheel or estimated crank hp figures?
At the rear wheels. Pete at Performance dyno says 318 at the wheels equates to 430 at the crank. I thought that sounded like a lot of parasitic loss- I always thought 15-20% loss off bhp would give you wheel hp.
From what I have been reading about Dynos - --all the"kids" on the ricer forums brag about their numbers---there is a large amount of variability from dyno to dyno. In fact, the various types show as much as 20% - 30% difference in results because of the mechanical designs.
I ran my MS3 on the Dyno Dynamics machine at Dent Sport and it gave me 240 WHP and 270 WTQ, with the only mod being the Cold Air Intake. Supposedly, the results on a Dyno Jet would have been around 260-270 WHP. Just for reference sake, Mazda claims 263 crank HP. Lots of number scattered all over the board, right? :shock:
Which is more "accurate"? Ha, don't even go there! Everyone has an opinion. Rule of thumb is to use the same machine for any subsequent testing. Even then, Air temp, Humidity, Atmospheric pressure, phase of the moon, etc., will vary results by 5 -10 %, or more.
As for your parasitic loss, have you thought of putting fluid in your transmission and grease in the rear end? :lol:
It will be fun for the rest of us to watch you guys "go at it" this year! You are certainly some very capable drivers!
Sam
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Post by jlwhorf » Wed Apr 02, 2008 8:59 am

Scott,

Big torque is what you want. Given the 15-20% rule of thumb, that gives you in the area of 450 lbs/ft. As quoted from the cam help guy at comp cams, "All the hp in the world won't do you any good without torque". I'd be pretty happy with those numbers.

Jonathan

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Post by jrottn » Wed Apr 02, 2008 10:10 am

I dont know much about Marios car but I do know a bit about the macaroons.com-mobile
James doesnt frequent these forums so I have been OKd to post some info on his car
The car probably comes in at 2750 or so lbs
hp @ crank 410 (using 17.5 loss = 339 rwhp)
lb/rwhp= 8.11
The car made more torque than hp although I forget the #
The advantage of this car is ability to put the power down out of corners
The disadvantage of this car is gearing- 4 spd with very tall gears (most people gear down or go 5-speed as top speed in 4th is over 200)
Im hoping my car has slightly better power/weight although current dyno #s are 0.0 for hp and trq
john bradshaw
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Post by brucesallen » Wed Apr 02, 2008 11:23 am

jlwhorf wrote:Scott,

Big torque is what you want. Given the 15-20% rule of thumb, that gives you in the area of 450 lbs/ft. As quoted from the cam help guy at comp cams, "All the hp in the world won't do you any good without torque". I'd be pretty happy with those numbers.

Jonathan
Hmmm. As soon as the wheel starts turning torgue becomes horsepower. A tiny bit of horsepower can be turned into infinite torque with proper gearing. Tell that guy about the math.

My Lotary 7 is down at Dent Sport having a new Garrett single turbo manifold welded up and Power FC computer set up. Should I bring the 1,800 lb. former SPA champ out again?
Bruce Allen
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Post by offcamber09 » Wed Apr 02, 2008 12:27 pm

[quote="brucesallen Should I bring the 1,800 lb. former SPA champ out again?[/quote]

Hell no, I thought we rid ourselves of that PROBLEM. Next you're going to tell me Greg Read is coming back to the class. :roll:
Scott Rosnick
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Post by TroyV » Wed Apr 02, 2008 12:44 pm

Scott, do you have the dynojet runviewer files? If so, can you email them to me?
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offcamber09
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Post by offcamber09 » Wed Apr 02, 2008 4:03 pm

TroyV wrote:Scott, do you have the dynojet runviewer files? If so, can you email them to me?
All I got was a graph. It's posted on the SVTOA forum.
Scott Rosnick
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Post by John F » Wed Apr 02, 2008 5:20 pm

Good numbers, Scott. What's in that Mustang? My 302 has 355 RWHP and 365 RWT with 6 psi boost. EFI, though, so limited to 6250 rpm.
Dyno Jet numbers with 3:55 gears
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Post by zip4zat » Wed Apr 02, 2008 6:10 pm

offcamber09 wrote:[quote="brucesallen Should I bring the 1,800 lb. former SPA champ out again?
Hell no, I thought we rid ourselves of that PROBLEM. Next you're going to tell me Greg Read is coming back to the class. :roll:[/quote]

Almost, Greg Read's CAR will be a frequent participant with COM this year.
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Post by offcamber09 » Wed Apr 02, 2008 7:02 pm

John F wrote:Good numbers, Scott. What's in that Mustang? My 302 has 355 RWHP and 365 RWT with 6 psi boost. EFI, though, so limited to 6250 rpm.
Dyno Jet numbers with 3:55 gears
John,
331 stroker, twisted wedge unmolested heads, 9.3:1 CR, shorty headers, Anderson Ford cam and an intake that chokes the chicken at 5400 rpm (GT40).
Numbers were also on a Dyno Jet with 3:55 gears.


Joe,
Greg is still in PA or has he dropped down?
Scott Rosnick
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Post by Mark Swinehart » Wed Apr 02, 2008 7:29 pm

Scott -

Joe didn't say anything about Greg driving.

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Post by offcamber09 » Wed Apr 02, 2008 8:40 pm

Mark Swinehart wrote:Scott -

Joe didn't say anything about Greg driving.
I stand corrected- who bought the car? Let them know it's a PA car- will ya? :wink:
Scott Rosnick
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