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Re: 968 Turbo boost problems whilst mapping
Posted: Fri Mar 21, 2025 10:54 am
by Thom
See
here.
Around 400 hp and 700 N.m at 4000 rpm.
Re: 968 Turbo boost problems whilst mapping
Posted: Sat Mar 22, 2025 3:31 am
by Rickuk1
Thom wrote: Fri Mar 21, 2025 10:54 am
See
here.
Around 400 hp and 700 N.m at 4000 rpm.
Wow great figures
Re: 968 Turbo boost problems whilst mapping
Posted: Sat Mar 22, 2025 5:31 am
by Thom
Thanks.
In what gear was your dyno run done? I assume you still run the original 968 gearbox and ratios?
Re: 968 Turbo boost problems whilst mapping
Posted: Sun Mar 23, 2025 1:34 am
by Rickuk1
I think it was in fourth gear for the run. The gearbox is 968 standard box other than limited slip differential.
Re: 968 Turbo boost problems whilst mapping
Posted: Sun Mar 23, 2025 2:12 am
by Thom
I can't remember exactly but I suppose the 4th gear ratio in the 968 gearbox may be about as tall as the 3rd one in the 944 turbo gearbox, meaning you may want to try doing dyno runs in at least 5th gear as the extra load should help spooling the turbo earlier.
Re: 968 Turbo boost problems whilst mapping
Posted: Mon Mar 24, 2025 6:52 pm
by 333pg333
...
Re: 968 Turbo boost problems whilst mapping
Posted: Tue Mar 25, 2025 12:29 am
by Thom
Looks like a comparison of the 944t ratios with the regular 944's?
Here is the diagram for the 968 'box :

- _20250325_083611.JPG (122.6 KiB) Viewed 4355 times
Re: 968 Turbo boost problems whilst mapping
Posted: Tue Mar 25, 2025 5:02 pm
by 333pg333
Hmm, you're right. Not sure what happened there. I've removed it. You're also correct Thom re the 951 4th gear vs the 968 5th gear. Very close in road speed.
https://members.rennlist.com/951_racerx/gearing.html
Re: 968 Turbo boost problems whilst mapping
Posted: Wed Mar 26, 2025 6:43 am
by Thom
Well, I am wrong re 951 3rd vs 968 4th, as the gap between these two is much larger than for 951 4th vs 968 5th.
It still seems correct to me though to perform a dyno run in 5th with a 968 'box with stock ratios, at least with such an engine set up.
Re: 968 Turbo boost problems whilst mapping
Posted: Thu Mar 27, 2025 5:18 pm
by 333pg333
According to the chart in that link. 951 in 4th gear is doing 21.2mph per 1000rpm and the 968 is doing 21.50mph in 5th gear under same conditions with same size tyre. So yes, testing in 5th with a conventional 968 transmission is most suited.