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It's Back - 3.7 Content *Now With Prelim Results*

PPBB

Off-topic, could I ask what ride heights are you running on your car?, taken form the Porsche suggested points.

How close is your FVD oil pan to the floor with those heights?

Cheers
 
Looking good poppop. Good to see it's back.

What benefit does the Motorsport AOS have please? And how does it compare price wise? I know most Porsche Motorsport parts are usually cheaper.

I'm interested in the IMS bearing goes as the roller type is top of my list should I need to change mine.
 
Looks great.

Is it possible to turn a 3.6 into a 3.7 (by shortening the rods), then? Or are the engines just too different?
 
EGTE said:
Looks great.

Is it possible to turn a 3.6 into a 3.7 (by shortening the rods), then? Or are the engines just too different?

I'd imagine whilst he's retained the original 3.4 heads, he's had them bored out to increase the capacity, plus fitted bigger pistons, unless I have the wrong end of the stick.
 
Different liners and pistons for larger capacity, not sure of the details on the head.
I am suprised that this isn't done more often if people need a rebuild. If ever my 3.4l engine needs a rebuild this is what I will be doing. In fact, it is something I might consider anyway with a spare engine I have.

MC
 
Excited for the figures! :worship:
 
EGTE said:
Looks great.

Is it possible to turn a 3.6 into a 3.7 (by shortening the rods), then? Or are the engines just too different?

No, in short :) If you shorten the rods you will still have a 3.6 just with a lower compression ratio.

3.6 and 3.4 share a common bore, the 3.6 just has a longer stroke crank. If you do the same as I have done (100mm bore) on a 3.6 then you'll get a 3.9L motor, although as I mentioned in my earlier post I didn't want to go 3.6 crank in mine as I wanted to keep the piston speeds low, the pistons I am using are lighter than the OEM ones so rod loads are actually lower now than the were as standard.
 
crash7 said:
PPBB

Off-topic, could I ask what ride heights are you running on your car?, taken form the Porsche suggested points.

How close is your FVD oil pan to the floor with those heights?

Cheers

It is max allowable for a Mk1 GT3 so 112mm front and 135mm rear. This gives me 10mm either side of this to play with as needed but in reality it tends to stay at these heights, the slightly less rake than a GT3 usually runs helps a little with stability on the road.

The pan very rarely scrapes anything, mainly because the exhaust manifolds are lower than the pan by about 10mm so tend to act as useful mechanical bump stops. The car also has quite a bit of low speed compression damping in the rear shocks which helps to avoiding it loosing too much heigh over speed bumps and pot holes.
 
Marky911 said:
Looking good poppop. Good to see it's back.

What benefit does the Motorsport AOS have please? And how does it compare price wise? I know most Porsche Motorsport parts are usually cheaper.

I'm interested in the IMS bearing goes as the roller type is top of my list should I need to change mine.

The Motorsport AOS is a twin chamber design with more capacity than the standard item which amongst other things means it avoids the smoke on circuit with sticky tyres that sometimes happens with the standard AOS. Apparently they are a bit more reliable too but I think that is mostly anecdotal as I doubt the KMs have been done on the Motorsport version to validate that against the standard part!

Image from Rennpart:
MotorsportAOS2-1500x1500.jpg
 
poppopbangbang said:
Marky911 said:
Looking good poppop. Good to see it's back.

What benefit does the Motorsport AOS have please? And how does it compare price wise? I know most Porsche Motorsport parts are usually cheaper.

I'm interested in the IMS bearing goes as the roller type is top of my list should I need to change mine.

The Motorsport AOS is a twin chamber design with more capacity than the standard item which amongst other things means it avoids the smoke on circuit with sticky tyres that sometimes happens with the standard AOS. Apparently they are a bit more reliable too but I think that is mostly anecdotal as I doubt the KMs have been done on the Motorsport version to validate that against the standard part!

Image from Rennpart:
MotorsportAOS2-1500x1500.jpg

I had the motorsport AOS on my previous 996..... it failed at around 40K and 6-7 years old. :sad: the problem was then trying to find another as the Reg number showed a standard AOS but i think from memory the garage said the pipes were in different places?.... Whatever I'm not sure its the cure to all AOS woes - maybe i just had a duff one!
 
poppopbangbang said:
EGTE said:
Looks great.

Is it possible to turn a 3.6 into a 3.7 (by shortening the rods), then? Or are the engines just too different?

No, in short :) If you shorten the rods you will still have a 3.6 just with a lower compression ratio.

3.6 and 3.4 share a common bore, the 3.6 just has a longer stroke crank. If you do the same as I have done (100mm bore) on a 3.6 then you'll get a 3.9L motor, although as I mentioned in my earlier post I didn't want to go 3.6 crank in mine as I wanted to keep the piston speeds low, the pistons I am using are lighter than the OEM ones so rod loads are actually lower now than the were as standard.

Oh I had no idea - I thought the 3.6 was bigger bore hence why it was more susceptible to bore score and ovalling
 
I can confirm that extra mid range is quite significant. We are currently road testing a 996 3.4 converted to 3.7 (100mm pistons), a 996 3.6 converted to 3.9 (different 100mm pistons) and a 997 3.8 converted to 3.9 (same pistons as the 3.6) - all with Nikasil alloy cylinders.

We will also be building a 3.2 Boxster S into a 3.7 and Cayman S 3.4 etc using many common parts for our oversized engine range (just need to finish testing the others before moving them on so we can get in the other models we intend to offer in the range).

All testing is going well and we hope to be taking orders later in the year.

Although it is theoretically possible to change the 3.2 and 3.4 engines right up to 3.9 (or more) to do it reliably would require many more parts to be changed and updated at significantly greater cost for relatively little extra performance and after all that you would question the brakes and suspension etc - so for now we are limiting our future conversions to those ranges.

Also in build a Gen 2 - 4 litre car - something for next winter perhaps?

Baz
 

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