onefastviking

So someone asked me this question today, "Which is better for getting into Spec 996, a 3.4 car or a 3.6 car ?

The weight is higher on the 3.6 cars, what power differences are you guys seeing between the cars ?
Any of the Spec 996 guys dyno their cars ?

I know what I can get out of a 996,both 3.4 and 3.6 as I have done both, for NASA GTS, but that rule set allow us to do a lot more to the cars that the PCA Spec 996 rule set allows.

jrgordonsenior

Using the easily accessed weight/fwhp figures the 2850lb 3.4 has a weight/fwhp ratio 9.63. The 3040 3.6 is 9.38 a small difference. The 190 lb. penalty for the additional 29 fwhp available with the 3.6 is only a 6.55 ratio which appears to favor the 3.6 as the better choice.

Longevity should also play into the equation. I've heard the 3.4 has a stronger crank, and I believe have less IMS bearing failures at least from what I've seen out West.

All the above make for an interesting choice. Of course I'm prejudiced towards the 3.4 as it's served me well for the past 3.5 years. I've run side by side with many 3.6's and 3.6 X51's in weight/whp classes and neither is noticably faster then my 3.4. Additionally, you should be able to outbrake the same car that's carrying an additional 190 lbs. and identical brakes. But hey, what do I know........

TRT41

+1 But hey, what do I know........ it's all about the drover. For now I have the only 3.6l SP996, we seem to be fairly matched on short and long tracks. At TWS the best times were with in a .5 second. I know the car has more...
I'd look at donor car cost and engine replacement cost if I were starting over, since at the margin the other spec parts all cost the same

onefastviking

JR , you ran as a Spec 996 for awhile didn't you ? What did your car dyno at in Spec 996 trim ? What does it dyno at now in non-Spec 996 trim ? If I'm allowed to ask ?

onefastviking

Have you dyno'd your car ?
I'm just curious how these are dyno'ing in Spec 996 trim. The 3.6Liter cars, and the 2000 996 3.4's should be at a slight power advantage from what I am seeing.

TRT41

I have not dyno'd yet, but I may do some NASA events this summer, so I've get it done then. I'll give you an update ASAP.

onefastviking

Come out to the April NASA event at TWS, it should be fun and I will be there to help out should you need anything. MG will be out there in his new Miata I believe, or his 996, who knows.

The black slightly modded 996 will be out again looking for a new track record in the 45's, and I believe we will also have a driver for the Boxster this time around at TWS to see what it can do.

mglobe

Yup, I'll be there in the Pinata

Ritter v4.0

From my limited experience similarly prepared 3.4 (284 whp) vs. 3.6 (305whp) shows on a faster longer track like Sebring with the edge to the 3.6 (but this is in the context of NASA where the 3.6 may not be carrying the full $1.90 as it would in Spec). 3.6 just has more jump out of corners that really seems to pay off. Much less so on shorter, slower more technical tracks like Barber.
For tracks in between like Road Atl its pretty even but managing traffic becomes critical. Loss of momentum is a real buzz kill for the 3.4

But I'd love to hear more from the Spec guys on this.

onefastviking

But are those numbers for a Spec 996 ? And on what dyno ?
Spec 996 requires,
stock TB,
stock airbox,
stock ECU / programming,
stock 996(not X51 or S) headers,
etc etc.

Ritter v4.0

No. As mentioned, in non-Spec context. But I offered in this light as I wondered if there was a correlation back to Spec.
Dynojet dynos btw.

mglobe

I'm assuming the 284 number for the 3.4 was with a non-stock intake, headers, and an ECU flash?

If I can ever get my mechanic to build a new exhaust for my 3.4, I'll put it on a dyno and post the results.

Ritter v4.0

Cheap eBay ss headers, no-cat exhaust + remap but I think the airbox was stock back then.

Have him make something like this- the weight loss alone is worth the price of admission.

onefastviking

That is a data point although I'm not sure how close to accurate it is for the Spec 996 guys, if that were the case I'd post a 340+ 3.6liter dyno chart but that one is kind of irrelevent for them because they can't do all that I have done to that 996 3.6L.

The Spec 996 guys are allowed open exhaust but must run a stock header and stock ECU mapping, I am guessing that will take them down to 270'ish or less for the 3.4, and maybe high 280's for the 3.6. But that is all just speculation without seeing some real world dyno runs, and even then there are always differences between dynos.

MG is just playing with me. I'm working on your exhaust MG, it will be done next week and we will dyno for sure.

mglobe

Yeah, just giving you shizit.