Horsepower Guesstimate

[Don Supreme]

I am curious.

Given my trap speed (119.77), typical 1/4 mile A4 performance.... What do you think my AWHP numbers might be?

[gotaudi]

~340-360AWHP is my guess

[spxxx]

what is your setup?

[Don Supreme]

^ Personally the car feels around that range, but the numbers don't match.

I have seen 400 AWHP audi's trap around 114 or so... and most 28 series making 300 -330 awhp trap around 108-109... You need more than 30 AWHP to trap 10 MPH higher.

[Poopie]

7 unicornpower.

[gotaudi]

7 unicornpower.

LOL

[gotaudi]

^ Personally the car feels around that range, but the numbers don't match.

I have seen 400 AWHP audi's trap around 114 or so... and most 28 series making 300 -330 awhp trap around 108-109... You need more than 30 AWHP to trap 10 MPH higher.

A Stage 3 S4 will put around 400WHP down, they weigh about 300Lbs more, and will do what you do in the 1/4 mile on pump (i think) so for you to get the same time with less wieght your Hp would be less. Just go get it dynoed.

[bernB5]

how much boost were you running?

[bassed]

7 unicornpower.

.1 Noobercorns


I'm thinking about 360ish

[Solaris]

See what this calculator on dragtimes.com says

[Don Supreme]

A Stage 3 S4 will put around 400WHP down, they weigh about 300Lbs more, and will do what you do in the 1/4 mile on pump (i think) so for you to get the same time with less wieght your Hp would be less. Just go get it dynoed.

I will never know, because we are about to pull the head off and when it goes back on............... well you can guess the rest.

[gotaudi]

what are your plans for the head?

[fred2ka4]

I will never know, because we are about to pull the head off and when it goes back on............... well you can guess the rest.

Well if you are about to pull the head off, then you should dyno the car because if you plan to do some head work You should want to see what the gains are.

[Don Supreme]

.1 Noobercorns


I'm thinking about 360ish

You guys will see when you run your car @ the track.......

I have used those calculators and I just dont know. For example I used the calculator @ dragtimes.com and it said

Horsepower @ flywheel = 429.90 HP

So I figure 430 * .75 = 322 AWHP................... THERE IS NO WAY YOU CAN TRAP ~120 MPH in this car with only 322 AWHP.

[Don Supreme]

Well if you are about to pull the head off, then you should dyno the car because if you plan to do some head work You should want to see what the gains are.

no can do....

not pulling the head because I want to.

P.S. Can a mod please fix the title of this thread.

[Poopie]

you can change it yourself. Just double click the title box in the b5 forum page. I was gonna run this weekend but it looks like rain.

[Solaris]

You guys will see when you run your car @ the track.......

I have used those calculators and I just dont know. For example I used the calculator @ dragtimes.com and it said

Horsepower @ flywheel = 429.90 HP

So I figure 430 * .75 = 322 AWHP................... THERE IS NO WAY YOU CAN TRAP ~120 MPH in this car with only 322 AWHP.

I don't think the drivetrain loss % is constant for all levels of power, so it would be a little less for you. For instance, if a 200HP car makes 150AWHP, why would a 400HP car make 300AWHP while moving the same drivetrain? It should cost the same 50 or so HP.

[Don Supreme]

you can change it yourself. Just double click the title box in the b5 forum page. I was gonna run this weekend but it looks like rain.

Thanks for the tip.

Dammit Poopie you need to do something!!!!!!!!!!!

But honestly what are you expecting?

[Don Supreme]

I don't think the drivetrain loss % is constant for all levels of power, so it would be a little less for you. For instance, if a 200HP car makes 150AWHP, why would a 400HP car make 300AWHP while moving the same drivetrain? It should cost the same 50 or so HP.

The great debate...................

I took the best Audi A8 time from dragtimes and plugged it into their calc

12.6 @ 113.020
Weight = 3605

They estimate 381.19 HP ---------- Audi says the car makes 420+


You see what I mean?

[CaSp3r9]

You guys will see when you run your car @ the track.......

I have used those calculators and I just dont know. For example I used the calculator @ dragtimes.com and it said

Horsepower @ flywheel = 429.90 HP

So I figure 430 * .75 = 322 AWHP................... THERE IS NO WAY YOU CAN TRAP ~120 MPH in this car with only 322 AWHP.

That's if you're losing 25% of your power through the drive train, which I can pretty much guarantee is not the case. I believe that's for stock HP numbers and even then 25% is on the high side IIRC; I think it's around 23%). The more HP your car has, the less power you lose through Quattro, as a percentage - even though the number of horses(or unicorns) lost is greater.
I don't really think losing 107.5hp with Quattro is realistic at the 430hp mark. Instead, let's say you lose 18% through Quattro at the 430hp mark, which is 77.4hp. That puts you at 352.6awhp, which is more realistic.

Correct me if I'm wrong, because I probably am. I'm just going off what makes sense to me.

[AudiA4_20T]

I think your not making anything because you need to get your car moving first

[CaSp3r9]

I don't think the drivetrain loss % is constant for all levels of power, so it would be a little less for you. For instance, if a 200HP car makes 150AWHP, why would a 400HP car make 300AWHP while moving the same drivetrain? It should cost the same 50 or so HP.

You beat me to it! Glad to see I'm not the only one that believes this.

[Poopie]

i would like to trap atleast 120mhp on race fuel which is about 400awhp. No clue on ET, maybe high 11's

[CaSp3r9]

Mike needs to chime in, I remember him talking about this but it was a looong time ago.

[Don Supreme]

You beat me to it! Glad to see I'm not the only one that believes this.

Lets not go down that road on this thread. We are talking about trap speed as it relates to HP in a Audi A4 (B5 or B6). I don't see 350AWHP trapping 120 in this heavy ass car.

Audi r8 makes 420 CHP and traps 113 mph.
04 gallardo, AWD, 500 HP, weighs less than an A4, traps 118 +.

[CaSp3r9]

Lets not go down that road on this thread. We are talking about trap speed as it relates to HP in a Audi A4 (B5 or B6). I don't see 350AWHP trapping 120 in this heavy ass car.

Audi r8 makes 420 CHP and traps 113 mph.

What road? I think you misunderstood me... I was just saying I'm glad I'm not the only one that thinks the percentage of power lost isn't constant at every HP level...

Or did you mean about Mike? I said that because I remember him having some valuable information about HP loss through the drive train at different HP levels. Trust me, I'm the last person to try and start any drama on here.

[Poopie]

Well I an one to believes that it IS a constant %.

The drivetrain loss is from the drag coefficient from the moving parts. It is a multiplying FACTOR so in all power levels so it remains the same.

[Don Supreme]

Ok this is for Poopie and for the trap speed to AWHP in an A4 discussion.

You'll be able to make more than 330whp on pump with the 3071R
With only 17psi I did 320awhp,25psi 415awhp on race gas.
I was being conservative only revving to 7200rpm & using lower boost than I usually do.

After my first spinned, I got another set of exprimental Cats (asymetric) that are pinned.
Used them once at the track ran 12.2@114 with a 1.9 60'
No dyno as yet.
Too much wheelspin.
It maybe better to get billets...

confirmed 400 AWHP and trap speed is < 115 .............................

[Poopie]

dooohhh....thats ok. With the wheel spin and just an okay 60ft time and he still managed a low 12 run, 11's seems obtainable. Although his post a little ambiguous on what boost and such he ran at.

400 awhp with 23% DTL is still 512 hp at the crank.

[Don Supreme]

^ I am not talking about ET......

Lots of things affect ET. I am sure you can run low 12s, but trapping 120 is another story.

[Poopie]

so with all things said....you must be at like 430-440 whp mark right? Just hit the dyno. Plan to drive up in a month and we can all hit a dyno

[CaSp3r9]

Well I an one to believes that it IS a constant %.

The drivetrain loss is from the drag coefficient from the moving parts. It is a multiplying FACTOR so in all power levels so it remains the same.

Yeah, I'm really not sure. I was just going off of what makes sense to me. It seems like the percent of power lost would stay constant but losing 100hp through the drive train at the 400hp mark doesn't make much sense to me, it seems like a lot.

I was kinda looking at it like a terminal velocity problem; an skydiver can only fall so fast, he doesn't keep accelerating for as long as he falls. Such that, you can only lose so much power through the drive train before it hits a plateau. If this is the case, the percentage of power lost would be inversely proportionate to the amount of hp you're making.

Now I REALLY wanna know the answer to this haha

[Poopie]

well that is a bad example because it actually works agains you.

in both comparisons you have a force, gravitational and a combustion force. Both forces result in something increasing in velocity at an exponential rate. The opposite force is friction. You can say there is a point where there is so much friction at a certain level to stop HP from developing as well.

[Don Supreme]

so with all things said....you must be at like 430-440 whp mark right? Just hit the dyno. Plan to drive up in a month and we can all hit a dyno

who knows.....

When I get everything wrapped up, I don't know if I even have enough injector to safely run on the dyno.

[Poopie]

are you running 630s? I think you should be fine. Do some loggon on the way up. lol

[Don Supreme]

are you running 630s? I think you should be fine. Do some loggon on the way up. lol

yeah - 630s @ 4 bar ( some say thats 730cc)

[CaSp3r9]

well that is a bad example because it actually works agains you.

in both comparisons you have a force, gravitational and a combustion force. Both forces result in something increasing in velocity at an exponential rate. The opposite force is friction. You can say there is a point where there is so much friction at a certain level to stop HP from developing as well.

True, I see what you mean. I was looking at it differently which is prob why it doesn't work.

[Poopie]

yeah - 630s @ 4 bar ( some say thats 730cc)

I think thats plenty of injector. I though 630s at 3 bar could support up to 500 whp on a 4cylinder engine.

[Don Supreme]

I think thats plenty of injector. I though 630s at 3 bar could support up to 500 whp on a 4cylinder engine.

ahhhhhh, I have never seen anything like that.... maybe 500 chp - 550...


I think I have seen 480 FWHP, but that may have been 4 bar and I know it was on race.

[Poopie]

hmmm i think you are right. 500chp sounds about right

an s4 with rs4/rs6 hybrids made a tad over 500whp on pump gas with 630s at 4 bar with 95% injector duty cycle.