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Hi,

 

Figured it would be interesting to know what your PWR or target PWR is:

 

Weight = full of fuel ready to race no driver

Power = Wheel horse power

 

PWR = Weight / Power (I know it's reversed)

 

It was thread about this a few years ago but given some rule changes and more competition I think that has changed. This is our car:

 

2006 NC Miata, headers, CAI

2366 lbs

165 whp

 

PWR = 14.33 

 

Our HP is pretty peaky,at 4500 RPM it's a turd. 

 

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New meaning to #FLATTENTHECURVE    

Math isn't working for my car(s) right now.   Both are pretty light at the moment.    E36 is probably ~2100 ish lbs as it sits without driver Datsun has to be ~1700 ish, maybe

There's much to be said for bigger engines that make the same hp. There's also a weigh penalty that comes with that but that's what compromise is all about.   I've mentioned it before but I

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25 minutes ago, QuaTTro said:

For our 1990 Audi Quattro sedan:

 

Race Weight: 2700lbs

Crank HP (factory): 164hp

Estimated Wheel HP:  130 (assuming 20% AWD loss)

 

PWR is a measly 20.7

 

You have plenty of points, here is some inspiration:

 

220px-Audi_S1_Pikes_Peak.jpg

 

 

Hold on, is your a turbo??? If so, no excuses

Edited by turbogrill
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34 minutes ago, turbogrill said:

 

You have plenty of points, here is some inspiration:

 

220px-Audi_S1_Pikes_Peak.jpg

 

 

Hold on, is your a turbo??? If so, no excuses

We're not a turbo..just a 2.3L NA motor.

 

I suspect we could save about 200 lbs if we got really creative but my team doesn't want to "drive a car with floppy doors/hood and compromised structure".  So we're saving in little places where possible.  

 

Our future plan is probably to swap in a 1.8t from another modern Audi A4, and maybe by playing with boost we can get closer to 200hp and have a decent PWR.

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58 minutes ago, QuaTTro said:

We're not a turbo..just a 2.3L NA motor.

 

I suspect we could save about 200 lbs if we got really creative but my team doesn't want to "drive a car with floppy doors/hood and compromised structure".  So we're saving in little places where possible.  

 

Our future plan is probably to swap in a 1.8t from another modern Audi A4, and maybe by playing with boost we can get closer to 200hp and have a decent PWR.

After the rebuild, and all the nice valvetrain upgrades, I would vote for you guys to get more aggressive cams for the 2.3 and rev it higher. I like the way those sound... even more above 6500 rpm.

 

I bet you could find cams that would get you to 200 hp (though a bit higher in the RPM range than you race now) and have decent durability with lightweight internals...

 

 

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40 minutes ago, CBraden said:

After the rebuild, and all the nice valvetrain upgrades, I would vote for you guys to get more aggressive cams for the 2.3 and rev it higher. I like the way those sound... even more above 6500 rpm.

 

I bet you could find cams that would get you to 200 hp (though a bit higher in the RPM range than you race now) and have decent durability with lightweight internals...

 

 

There may be a few Cam options, then we'd also need to go to standalone ECU and possibly race gas to get those hp numbers, or maybe increase our displacement a little.  What holds us back most from doing this is budget.  

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1 minute ago, QuaTTro said:

There may be a few Cam options, then we'd also need to go to standalone ECU and possibly race gas to get those hp numbers, or maybe increase our displacement a little.  What holds us back most from doing this is budget.  

 

While I know nothing of Audi performance mods... I know on my platform cams alone can get 50% gains... race gas is really only required if you are raising compression beyond some reasonable number. It was a suggestion based on what I know (which may not apply at all to Audi 5 cylinders). I think you may know somebody who has knowledge of tuning factory Audi ECMs - but perhaps yours is before they started finding ways into them... I like your engine and would like to see it continue racing. just my opinion... and not my checkbook :)

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51 minutes ago, mender said:

Fiero: 2550 lbs, 186 whp = 13.7:1

Civic: 1913 lbs, 133 whp = 14.4:1

 

Since you asked:

Target PWR = 8.75:1 :)

 

Ours is a shade less weight but less power too.

 

Civic: 1890lb, 140 rated crank hp.  Estimated 119 at the wheels = 15.9

Target after turbo = 1950lb, 175whp = 11.2

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3 hours ago, karman1970 said:

 

Ours is a shade less weight but less power too.

 

Civic: 1890lb, 140 rated crank hp.  Estimated 119 at the wheels = 15.9

Target after turbo = 1950lb, 175whp = 11.2

 

How do you do on fuel with the turbo?

 

How can they be so light????

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5 hours ago, QuaTTro said:

We're not a turbo..just a 2.3L NA motor.

 

I suspect we could save about 200 lbs if we got really creative but my team doesn't want to "drive a car with floppy doors/hood and compromised structure".  So we're saving in little places where possible.  

 

Our future plan is probably to swap in a 1.8t from another modern Audi A4, and maybe by playing with boost we can get closer to 200hp and have a decent PWR.

Any 1.8 turbo with K4 out of a Audi TT can make 280 HP with just a tune and live all day. 

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The last couple of WRL races we did, the rules put us in GP3 according to the dyno sheet and weight we registered on their scales which is like 15:1 or something like that.  I said I didn't want to run in GP3 that I wanted to be moved to GP2 or GP1 since that's the cars we would be realistically running against.  We have won 2 races overall and have a P3 overall in that series (I don't remember class positions because I don't care about them).  Point is, PWR although important is not the only significant factor.  I would however like to get lighter and crank out more power, so hopefully that puts us in the 13 range, we'll see.

Edited by Burningham
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14 hours ago, TiredBirds said:

No idea but if you want to figure it out... car + driver + gas is likely 3000lbs. Engine is a slightly modified 305 makes approx 315hp....maybe a tad more. and GO

You can't divide 3000 by 315?

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7 hours ago, Burningham said:

The last couple of WRL races we did, the rules put us in GP3 according to the dyno sheet and weight we registered on their scales which is like 15:1 or something like that.  I said I didn't want to run in GP3 that I wanted to be moved to GP2 or GP1 since that's the cars we would be realistically running against.  We have won 2 races overall and have a P3 overall in that series (I don't remember class positions because I don't care about them).  Point is, PWR although important is not the only significant factor.  I would however like to get lighter and crank out more power, so hopefully that puts us in the 13 range, we'll see.

 

Why would you want to move to GP2??

The top cars in GP2 has about a million points, at least at COTA the GP2 cars where nuts.

We want to downgrade from GP2 to GP3 :)

 

What car was this? 944?

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8 hours ago, wvumtnbkr said:

You can't divide 3000 by 315?

lol I was being silly

7 hours ago, mender said:

2800/275 whp = 10.2:1

 

You'll need more fuel. ;)

no kidddddding. Even with the extra 2 gallons we'd be hard pressed to make 2 hours. The car is going to go on a diet. We might be able to get it to 2900. We shall see. 

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13 hours ago, turbogrill said:

 

How do you do on fuel with the turbo?

 

How can they be so light????

 

We'll find out at Indy, if it happens this year.  Depending on actual power output and tuning, I'm guessing around 75 min per tank - if I get a cell bought and installed.  We get a max of 13.9 gallons to play with.  I've got an idea or two to improve the fuel consumption on down the road, but want to get the bugs worked out of it first.  By that point, the shell will probably be toast; so then we'll transplant all the mechanicals into an Intergra.

 

I don't know why it's so light, but I'm glad it is.  Even with 140hp we were getting walked by some of the Miatas at COTA.

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Cars I have helped with 

 

Stock 2.4 neon 2100 lbs 139 wheel hp   15:10  

Mod 2.4 neon  2100 lbs  160 wheel hp   13.12

Mercdes 230 SLK 2450   175 wheel hp   14

 

To be at front you will need close to or below 13:1 in a small car, 14 in a bigger car. Since the bigger cars have better power vs frontal area, they have better top speed for the same pwr. Really light cars at some tracks can get buy at lower PWR, same for cars with better tire wear (you can flog them).

 

Notice all of these wheel hp numbers exceed the target of the swap calc (which is in terms of crank hp, so correct that by 15 to 20%). You will need to tune or modify an engine from stock for most of the cars on the swap list to reach these goals. 

Edited by Black Magic
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