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Compression test - 944 S2

Too true. There are a number of issues I've been trying to resolve this year. I was originally running an early gearbox which last year made the car feel very nippy but as the box was never designed for S2 power the pinion detonated at Brands in Quali, so in went the S2 box. Made a noticeable difference, slower!

Had some handling issues due to new coilovers which I'm slowly getting my head around but even after running the longer ratio/slower S2 box for most of the season, the last two races I've really struggled and I was convinced there was a power issue.

I'm going to check the timing and get a borescope to be doubly sure but otherwise it must just be related to the ratios in box and less than ideal handling. That's pretty much all that's left that I can think of.

Geo on the front was checked a couple of weeks ago and is good, will throw the gauges on the rear and double check that end too.

Gearbox is off for a service next week and will have a lower ratio installed as well, although it may only need the final drive swapping out, that should help with lap times.


 
Hi Anthony,

We haven' tried the race car but Tom's road car produced 180psi on all four.

So I guess you're in the right area.

Gerry
 
Hi Gerry,

Is that an S2 as well and was that a dry test?

If it is, its in the same area but I would have expected the race engine to be a bit higher given it was a fresh engine last year.

There's no obvious signs of anything wrong except the chatty tappet but as it doesn't appear to be using any more oil than normal, there's nothing that immediately jumps out that would cause a loss of power. Althought it could be injectors but they were new when the engine was rebuilt.

The only way to know for sure is removing the head. A dyno run could help though. Might try and squeeze in a dyno run before Brands as that should provide a better idea in relation to power and air/fuel ratio.

Desperately trying to end our run of DNFs for the final race. A good result would be a bonus.

Are you going to Brands Gerry?
 
P1050036.JPG

Hi Anthony,

It's a S2 about 100K miles on the clock, tested with WOT and no extra oil in cylinders.

We probably won't do Brands, not sure our lights are good enough.

Gerry


 
Cater_Racer said:
We probably won't do Brands, not sure our lights are good enough.


Drop me a line if you change your mind and need someone to stand around and look decorative. [:)]


Oli.
 
Hey Gerry,

Thanks for the info and nice pic! Looks very tidy!

Yep lights is an issue. If the car is fit to race but if I run out of time to fit the lights I'll do the day race and cancel the night race.

Will hopefully be off for a dyno session in a couple of weeks once the gearbox has been reinstalled but it dawned on me earlier that the compression may be lower due to the cam reprofile. Although it's only mild the cross over has changed which I believe will give lower readings at low RPM and why it's a bit lumpy on idle.
 

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