Supra Forums banner

1 - 20 of 63 Posts

·
I'm back!
Joined
·
6,712 Posts
Discussion Starter #1 (Edited)
FINALLY got out to the track tonight. Had some major issues getting a good burnout, eventually I figured it out. This was at LACR, which is 2710ft above sea level, cutting a 2.05 60ft on BFG Drag Radials.

My best 60ft was 1.9, and I blew a coupler on that run. That run was well on the way to being a mid 10 second run without a doubt.

 

·
MKIV intervention needed
Joined
·
2,988 Posts
you were next to a 17 sec car LOL!!

nice run, i totally screwed up my first try at the 1/4 mile. time witheld.
 

·
19in 795R HRE's FTW....
Joined
·
6,305 Posts
Nice but you can't use a CF for the drag strip:) Doesn't quite work the same...
 

·
I'm back!
Joined
·
6,712 Posts
Discussion Starter #6
WOTM said:
Nice but you can't use a CF for the drag strip:) Doesn't quite work the same...
Why not? LACR straight from their web site.
http://www.lacr.net/week.html

Altitude Correction
LACR is 2,710 ft. above sea level.
To figure the altitude factor the formula is as follows:

ET: multiply your et (at LACR) by .97
MPH: multiply your mph (at LACR) by 1.03
This will give you the ET & MPH at sea level.

Everyone who runs there uses correction.
 

·
19in 795R HRE's FTW....
Joined
·
6,305 Posts
braddman said:
Why not? LACR straight from their web site.
http://www.lacr.net/week.html

Altitude Correction
LACR is 2,710 ft. above sea level.
To figure the altitude factor the formula is as follows:

ET: multiply your et (at LACR) by .97
MPH: multiply your mph (at LACR) by 1.03
This will give you the ET & MPH at sea level.

How did I know you'd ask why not...

Because in the real world you can't take a formula off a website just because it says you can.

I've been racing for many years Brad and I've been at 4000ft and 0ft and I KNOW how alititude does and does NOT affect mph and ET. Turbos change that formula quite a bit as well.

NO ONE EVER goes by a silly CF for racing ET's and MPH.

I assure you any racer will find it quite comical when someone goes by a "corrected" mph and et. You ever see record MPH and ET passes being "corrected? No...
 

·
I'm back!
Joined
·
6,712 Posts
Discussion Starter #8
WOTM said:
How did I know you'd ask why not...

Because in the real world you can't take a formula off a website just because it says you can.

I've been racing for many years Brad and I've been at 4000ft and 0ft and I KNOW how alititude does and does NOT affect mph and ET. Turbos change that formula quite a bit as well.

NO ONE EVER goes by a silly CF for racing ET's and MPH.
So you're saying trapping at 131mph with 800+rwhp is normal? Come on, the car is quite a bit slower at altitude, turbocharged or not. You could feel it driving it around.

The formula isn't perfect, but everyone knows running at LACR your trap speeds and ET are always lower than a sea level track.
 

·
Premium Member
Joined
·
2,887 Posts
braddman said:
Why not? LACR straight from their web site.
http://www.lacr.net/week.html

Altitude Correction
LACR is 2,710 ft. above sea level.
To figure the altitude factor the formula is as follows:

ET: multiply your et (at LACR) by .97
MPH: multiply your mph (at LACR) by 1.03
This will give you the ET & MPH at sea level.

Everyone who runs there uses correction.
I believe these correction factors (like those used on most dynos) are to correct for hp loss due to ambient conditions (including altitude). But turbo cars, unless they are badly outside of their turbo efficiency, do not lose hp at the same rate as a naturally aspirated or belt driven supercharger car would. This is the reason that you cannot accurately apply these correction factors (both at the strip and at the dyno) to your turbo car when above sea level. There are a lot of different factors coming into play, but the end result is that the correction factors tend to "skew" the numbers higher than they should be on turbo cars when dealing with elevation. Just my $0.02

Nice job for your first time out with the single!




John
 

·
I'm back!
Joined
·
6,712 Posts
Discussion Starter #10
John Reed said:
I believe these correction factors (like those used on most dynos) are to correct for hp loss due to ambient conditions (including altitude). But turbo cars, unless they are badly outside of their turbo efficiency, do not lose hp at the same rate as a naturally aspirated or belt driven supercharger car would. This is the reason that you cannot accurately apply these correction factors (both at the strip and at the dyno) to your turbo car when above sea level. There are a lot of different factors coming into play, but the end result is that the correction factors tend to "skew" the numbers higher than they should be on turbo cars when dealing with elevation.



John


John

Alright I can accept that. I ran 11.5 @ 131.
 

·
19in 795R HRE's FTW....
Joined
·
6,305 Posts
braddman said:
So you're saying trapping at 131mph with 800+rwhp is normal? Come on, the car is quite a bit slower at altitude, turbocharged or not. You could feel it driving it around.

The formula isn't perfect, but everyone knows running at LACR your trap speeds and ET are always lower than a sea level track.
Mph is a function of MANY things and never just horsepower.

I've been at LACR MANY times over the years. It's certainly slower but not THAT much slower. I race at two tracks in AZ that are 1900-2300ft.

Dyno horsepower as we all know is simply put, meaningless. It's good for tuning and nothing more.

I've run 170-171mph on the same setup with one dyno reading 1100rwhp and one reading 1300rwhp and the mph was the same at two tracks 1150 miles apart and 1800ft LESS elevation at one track than the other.

Point being, real world results are always more accurate than a formula online

And btw, stock motor with your turbo and setup you should be able to run 140-145mph with more boost, good tires, good driving, etc.
 

·
I'm back!
Joined
·
6,712 Posts
Discussion Starter #13
WOTM said:
Mph is a function of MANY things and never just horsepower.

I've been at LACR MANY times over the years. It's certainly slower but not THAT much slower. I race at two tracks in AZ that are 1900-2300ft.

Dyno horsepower as we all know is simply put, meaningless. It's good for tuning and nothing more.

I've run 170-171mph on the same setup with one dyno reading 1100rwhp and one reading 1300rwhp and the mph was the same at two tracks 1150 miles apart and 1800ft LESS elevation at one track than the other.

Point being, real world results are always more accurate than a formula online

And btw, stock motor with your turbo and setup you should be able to run 140-145mph with more boost, good tires, good driving, etc.
Yeah this was a lot of boost. 2 bar...so I don't really understand why the MPH was low..could that just be my shitty driving?
 

·
Inline for the win
Joined
·
4,727 Posts
Brad,

That was not a 10 sec run with your specs on your timeslip. Your car will do a 10 but not with that 1/8 mile status. Your 1/8 mile ET wasn't quick enough to be a 10.

Sorry.

Go back next time on the right wheel and tire setup or progressively ramp your boost.

DP
 

·
19in 795R HRE's FTW....
Joined
·
6,305 Posts
braddman said:
Yeah this was a lot of boost. 2 bar...so I don't really understand why the MPH was low..could that just be my shitty driving?
I think there's a few mph at a better track. I have no idea how your driving is but you could have boost leaks, or any number of issues.

It would also take 34-36psi to run 140mph+ with your setup
 

·
Premium Member
Joined
·
2,887 Posts
braddman said:
Alright I can accept that. I ran 11.5 @ 131.
What wheel/tire setup? Were you fighting wheelspin much? First time I raced a single turbo car (and mind you I don't have Ryan's amount of seat time) I went from around 131mph traps to 140mph traps in a car with similar power to yours. There was no change to the engine or power output from start to finish, I just got better at driving the car down the track. Elevation can affect it slightly (but no way to really know for sure, as the amount of effect will be setup dependent), track conditions, driving, air temp, winds, etc. So I expect with more time and maybe different track conditions you will find the mph will come up to what you expect, even at altitude.




John
 

·
Inline for the win
Joined
·
4,727 Posts
WOTM said:
I think there's a few mph at a better track. I have no idea how your driving is but you could have boost leaks, or any number of issues.

It would also take 34-36psi to run 140mph+ with your setup
I concurr with Ryan. However, you never stated your PSI while running at this level?

DP
 

·
I'm back!
Joined
·
6,712 Posts
Discussion Starter #18
Suprafied said:
Brad,

That was not a 10 sec run with your specs on your timeslip. Your car will do a 10 but not with that 1/8 mile status. Your 1/8 mile ET wasn't quick enough to be a 10.

Sorry.

Go back next time on the right wheel and tire setup or progressively ramp your boost.

DP

You misread. I had a 1.9 60ft run that was MUCH MUCH better that was on the way to being a 10 something run without a doubt. Not the one on the timeslip.
 

·
I'm back!
Joined
·
6,712 Posts
Discussion Starter #19
John Reed said:
What wheel/tire setup? Were you fighting wheelspin much? First time I raced a single turbo car (and mind you I don't have Ryan's amount of seat time) I went from around 131mph traps to 140mph traps in a car with similar power to yours. There was no change to the engine or power output from start to finish, I just got better at driving the car down the track. Elevation can affect it slightly (but no way to really know for sure, as the amount of effect will be setup dependent), track conditions, driving, air temp, winds, etc. So I expect with more time and maybe different track conditions you will find the mph will come up to what you expect, even at altitude.




John
BFG Drag Radials on the stock wheels, 275's..12psi pressure in the tires.
 

·
19in 795R HRE's FTW....
Joined
·
6,305 Posts
With a 1.90 you would have cut 2/10's TOPS and been at [email protected] To drop another 4 tenths for a 10sec slip you would have to cut a 1.70 60ft or pick up 6-7 more mph.

This I am also very sure of:)
 
1 - 20 of 63 Posts
Top