Dyno Tune Scheduled

[STU]

Just made an appointment to have the S1 dyno tuned by Brenspeed on Nov. 1. They are running tests right now on a driveshaft. 4 " dynatech I think. If they have it ready I will have them install and maybe get a before/after HP comparrison. I'll update then.

[07roushgt]

that would be neat to see what a driveshaft actually equals in hp.

careful with the 4", you will need to pound some metal out of the way!!

[STU]

As you have probably read I had my dyno tune today. Very happy with the results. Had the Steeda underdrive pulleys, Steeda aluminum driveshaft and Steeda strut tower brace installed. Tune with SCT Xcal2. The driveshaft install turned out great. No rubbing or vibration at all. It also cured my 28 MPH vibration which I diagnoised as coming from the stock driveshaft. I was right. I'll post the graph, couple pictures and 2 pull videos for those interested.



Dave & Brent






Guess I don't know what code to wrap the video links with?

http://cobrapages.com/videos/MOV00642.MPG

http://cobrapages.com/videos/MOV00644.MPG

[spindlecone]

Driveshaft upgrade, will get you no H.P Gains

[07roushgt]

did you do a before dyno run? if so what was it at?

[STU]

Originally Posted by 07roushgt

did you do a before dyno run? if so what was it at?

Sorry, was not able to get a before and after.

[STU]

Originally Posted by spindlecone

Driveshaft upgrade, will get you no H.P Gains

I think you are probably right. In their testing I don't think they saw any dyno improvement either but it is good for about 2 tenths on the quarter mile.

It did cure my vibration and I am very happy with it. Nice quality piece.

One thing they did say shows up on the dyno is heavy wheels. They thought my heavy forged wheels held me back slightly. They were dynoing a car once with hefty wheels and drag radials. The numbers seemed off to them. They jacked up the car and installed a stock set of Gt wheels they had around and gained 18 HP from the lighter wheel/tire combo.

[STU]

Originally Posted by spindlecone

Driveshaft upgrade, will get you no H.P Gains

I just wanted to add that while it may not net you much HP gain, the weight saving is pretty significant if you like twisties and performance driving. Any significant weight you can shed allows you to accelerate faster, brake later and pull more lateral G's.

[07roushgt]

i would be more interested in seeing if it changes the power curve any?

[STU]

Originally Posted by 07roushgt

i would be more interested in seeing if it changes the power curve any?

If you look at grabber07's graph our power curves are pretty much the same so it does not appear to have changed it any.

[grabbero07']

Originally Posted by spindlecone

Driveshaft upgrade, will get you no H.P Gains

I am going to have to disagree with you here. NO a driveshaft doesnt add horsepower...it frees up horsepower. We all have drivetrain loss.... the more we do to decrease the rotational weight on the car the more HP we will ge to the Rear wheels. By switching to an aluminum one-piece your first off getting rid of the nasty OEM 2 piece that weighs a ton.... your taking 27lbs of rational mass off the car.... For you road racing guys thats like switching to a light weight wheel...car will accelerate faster and takes less HP to turn the rear wheels. This is the reason they are claiming 2 tenths of a second in the quarter mile... more hp to the ground, less resistance on the drivetrain.

I know this thread is semi old but I thought I would throw in my 2 pennies...very good numbers by the way.

[spindlecone]

Ordered my leonard shaft yesterday, have talked with Ron the owner at lenth about the benis of the shaft.
His dyno results are minimal, maybe 8 H.P. but none the less a gain so I am wrong.
he also said the 2 tenths are on the conservative side, some people have seen 4 tenths.

[grabbero07']

Originally Posted by spindlecone

Ordered my leonard shaft yesterday, have talked with Ron the owner at lenth about the benis of the shaft.
His dyno results are minimal, maybe 8 H.P. but none the less a gain so I am wrong.
he also said the 2 tenths are on the conservative side, some people have seen 4 tenths.

WOW thats great! I hear the car feels a ton smoother throughout the RPM range...no more slop on the drivetrain..... Let us know your real world opinion after the install. I personally havent done this mod yet, but a close friend has and said he gained an honest 2 tenths...maybe a little more...so you are correct.

[STU]

Got to drive my car 4 or 5 times after the drive-shaft install and it definitely smoothed the car out at all speeds/RPM's. Was a great addition.