Jean

I don't really care about this discussion but for informational purposes, the maximum slope or ending slope do not matter to calculate the performance difference. Average slope across the run is what matters..

Gradient= Height/distance x 100.
Climbing KW required =(mass (Ton) x g x velocity x Gradient)/360,000, multiply result by 1.34 for HP.

An average 3% slope impacts 4.7% the power on the ground and 5.7% acceleration time difference on a 3500 lbs GT2RS with driver..

A GT2RS doing a 60-130mph in 6.02s on a perfect straight line does a 5.72s on a 3% average slope. It can only be calculated through a simulation model

2fcknfst

Jean; Porsche Sleeper Agent Extraordinaire...

Pb Pedis

This is where I am too - the balance is just right with my mods and how responsive it is on the road, so why mess with it? Because I don't know how to leave well enough alone.

onfireTTS

Exactly. Jean is top tier.

bigrpowr

i can attest to this when mine was a 3.85 and it was marked invalid due to 3% or just under. the next run a 1% was a 4.09 .

SamboTT@ByDesign

These real world things

Jean

We need to look at this as a percentage rather than absolute number i.e. a 5s run with a 3% slope benefits time by around 0.29s if all other parameters are identical.

By the way the 60-130mph started here on RL by a bunch of us on the 993TT forum in May 2004, way before the 6speed forum. Thread is still here with thousands of views, those were some really silly discussions 18 years ago.

geekcarguy

New to this thread, forum and to this platform also. And already hate seeing the mashing of other tuners / bs talk. Keep it civil folks!

But what I’m not new to is cars and performance times. I’ve been doing 100-200kmh (from Sweden) for over 15 years. Ofcourse slope has a great impact. And the only reason vbox allowed -3%, is because with their software on the computer, it would correct the slope. If you put in 4,86 on a-2.8% in the software it will show a corrected value of around 5.1s. That you’ve run a 4,9x with -0.9% slope is actually quicker then the 4,86s. And thats just how it is, that some have quicker times uphill sometimes can vary on many things, usually it’s the running conditions of the car, maybe it was pulling some timing on the other runs, maybe the shift points wasn’t as good. Maybe it was a different day and different DA. Etc etc.

anyways I really hope the thread starter gets his car sorted. I can only imagine the frustration of having spent that much money and it would be slower then stock turbo cars good luck with it!

But as many have stated. Take it to a different dyno, you’ll see straight away your not making near the quoted power.

Have a great day!

jsbihn

Hey my brothers,
So I have a new thought of discussion to continue to push forward with my current situation....
I know we have alot of really intelligent people on here from AIM, By Design, private builders, and so on...
So hopefully, this might get us thinking

Situation:
Send the car out for a big turbo upgrade kit, get the car back, take it out the first day back with my car acting completely fine and it was doing well for the first day out, i was out running with my buddy all day long full of aggressive driving, but then after the 10-15 mph from stop light low speed methanol issue... no issues after a code reset there has been no codes, no CELs, no smoking or any noise.
But the car started running a little slower... and the trans starts missing the shift from 1-2 and 2-3.... so the car returns to the shop.... ever since the car has had so many issues over and over.
tuning and retuning, has gotten it better but obviously you all know where i am now
it has become such a mess.... Would you think it is in the programming or wouldnt you think it is a broken or improperly performing hard part?
Thanks

Ttz06vette

Sounds like tuning to me, both engine and PDK. What do you mean when you say low speed methanol issue? Hoping you didn't continue aggressive driving if you had a methanol issue?

jsbihn

- pulled away from a light, at about 15-20mph maybe, i noticed the coast was clear... so I hit the gas, turbo start to spool and the car lights up like a christmas tree and every code porsche could think of. I limp home, scan the codes (write them down), then reset. Started the engine.... everything is fine. no CELs, no codes, no noises, no smoke, nothing dripping and so on.... and since then though the driving has been limited because of these other issues... no nothing.

as for the answer, why would you go with tuning versus a hard part malfunction?
just seems weird that from that point, it instantly ran bad and has had issues ever since that continuous tuning cant seem to fix...
(i figured a hard part and all the tuning isnt working because it cant correct for the hard part issue, so i would like to learn here :-) )

onfireTTS

Since you are running Cobb, post up a wide open throttle log to show the data.

Ttz06vette

It's possible you could have blown off a throttle body, intake, or turbo hose, but I'm guessing you checked all of that already as well as vacuum leaks. The fact that it's not throwing the codes again after reset is why I said tuning.

onfireTTS

"the first day back with my car acting completely fine and it was doing well for the first day out"

Any Dragy data when it was "completely fine" ?

jsbihn

- are you asking for me to datalog a wide open throttle log? like a 60-130 run? or are you saying post a picture of the cobb guage setup at WOT?

- True. I know that there are some issues that occur when small hoses come off and it messes up performance without throwing a code (like a small clear tube that is T'ed into and have a tendency to pop off)
Of course, I am not 100% sure the shop did the due diligence when it went back and they checked it all out. especially when the shop owner assured me that the car was supposely 100% perfect, but the day me and my wife drove 7 hours to pick it up... it displayed everything was the same. it has not been touched... other then them putting 300 miles on it. So I have a feeling there wasnt much attention to the engine to make sure everything is 100.

- unfortunately, i dont. i didnt have my dragy yet... it wasnt until the car slowed down that the i felt the need to test it out.