All things being equal, compared to the 9.5:1 engine, it'd have better throttle response and more off- boost torque. Where the meat of this conversation is is going to be in the effective compression ratio. There's a few engine specs needed to accurately calculate this that I haven't seen published (degrees ABDC the intake valve closes and rod length), and because the engines have independent and continuously variable cam timing, it's nearly impossible to say what the valve closing spec would accurately be. I mean, the factory service manual doesn't even state what numerical range a compression test should fall in, only that the lowest cylinder needs to be within 75% of the highest, so nobody can really say short of actually having done it on a fresh engine what the compression test pressure range should be.

But, for the sake of comparison, I took the specs (bore, stroke, rod length, intake valve closing spec) off a Windsor 302 and used the AJV8 compression ratios and boost pressure (9 PSI, not 27... lol) and came up with this:

11.5 compression ratio NA has a dynamic compression ratio of 8.49:1.
9.5 compression ratio SC has a dynamic compression ratio of 7.06:1.
9.5 CR SC engine @ 9 PSI has an effective compression ratio of 11.38:1.
11.5 CR NA engine @ 9 PSI has an ECR of 13.69:1.

I've personally run 4 cylinder turbos up in the 15- 17:1 ECR range on stock internals without issue, and plenty of guys run upwards of 20:1 ECR's with proper fuel, tuning and spark management. At the end of the day, this is all just a WAG and is pretty much worthless if you're really going to sit down and build an engine, but for the sake of us all just BSing here without actually having done anything with the AJV8, I'd say that from the mechanical standpoint, installing an XKR blower on an XK would not be a problem at all. The gotcha is going to be keeping detonation in check with what would be a razor thin detonation threshold; expect lots of timing being pulled to the point where it wouldn't make as much power as ut would on the 9.5:1 engine.

 

I thought 27PSI was rather high, but that what I found online from JLR intro to shop manual as applicable to F-type S.

 

I disagree. I think the elephant in the room is BUT WHAT ABOUT HEAT?

 

What about it? My post intercooler temps are about 40° higher than ambient, and my coolant temps are the same as the NA engine.

 

In honesty if the OP has gone to that much trouble he would be more inclined in going down the higher efficiency path of turbo's

 

The OP did a drive by, and I doubt they even own an XK.

 

It certain does appears that way

 

Odds are he doesn't even own a Jag. Provocatuer!

 

Mandrake, having seen "supercharger to a XK", and "Turbo to a 944" asked many times over the years, it has always been my observation that the poster is "angling" to not spend the additional $$$ of buying an XKR or 944 Turbo, but still get the same thing.

It just doesn't pan out that way. Yes you can supercharge or turbocharge a non factory boosted 944, and you can do the same with the XK. But I highly doubt the original posters that ask this have the dedication of money and time to spend. Its less expensive in money/time to just buy the boosted car from the factory.

 

My thoughts exactly, and I couldn't agree more.

 

+1. The OP hasn't been back since he started this thread.



What's the point of continuing this discussion?