800HP build Study: Use 4.2 R type or 5.0 R type
 

800HP build: Use 4.2 R type or 5.0 Supercharged as a baseline for installation into a jaguar that uses a 4.0 or 4.2 engine?

Recent posts on engine builds, supercharger porting and head porting started me thinking about what Jaguar V8 engine would be best to try to reach 800HP.

The 5.0 build thread posted by Dave Tibbs, https: http://www.jaguarforums.com/forum/xf...rebuild-177468
, leads me to believe that rebuilding a 5.0 engine is perhaps more difficult, time consuming and more expensive than beefing up and building a 4.2L to a 4.8L.

I‘ll presume that these builds will have to use a stand-alone engine controller, and probably have to use a manual transmission. (No way to remotely control either the ZF 6 or 8 speed transmissions.)

Seems that the 5.0 engine is a better designed engine. Direct injection, Inlet and exhaust VVT, Front fed Supercharger and a lot of other small details that they corrected in the 4.2 design. But as far as I can tell, no one has done any significant engine mods to date.

What do you guys think?
(Based on Avos hitting 700HP, what would one need to do to get to 800HP?)

Considering my setup as a base, with street fuel (98 octane we get here), it would be the following.

Design it for higher rpm, considering my flat power curve, just adding 500 rpm would already make a jump from 634 to 660 rwhp.

Work on the inefficient last 2 cylinders on the lh side, so manifold/exhaust and possibly airflow optimization after the Supercharger. That could add to possible 675rwhp.

In general optimize the airflow after the supercharger into the cylinders, via right cam design/vvt/intercooler/intake runners, where I would think this would increase efficiency so much that I would jump to 700 rwhp easy as it would also lower the power consumption of the supercharger, leaving more to the wheels.

Let’s assume that this already would be in the 800 ehp range.

Then there are many small things that are not optimized on my engine, as mentioned I use the stock manifold/exhaust , and of course the MB gearbox, going manual would yield also a bit, though not that much anymore as some may believe.

So all in all if you can design it from the ground up, the 800 ehp is not that far imo.

Strength of the block could be a concern that would count just as well for the 5.0 as the 4.2. For the latter RSR went for a stronger lower bedplate. I don’t dag/race, so the engine is less exposed to heavy thermal/stress loads.
I would think as well the 4.2 could be easier and one I use has shown it strength so far as well.

Nevertheless a TS setup on the 5.0 engine would be an interesting setup as well ;-)

...and when you reach 800bhp, you want 900hp and then 1000hp :) Power is not a problem when you have big motivation, a lot of time and enough deep pockets fto meet your target. Big power requires mods to almost everything. The big question is whether the car is a daily driver or you just want to run 9sec 1/4miles or something else.

Well, I was reading a magazine years ago. A shop owner bought an '84 Corvette for his girl friend. She dumped him before he could give it to her. That's probably why he bought it, as a bribe. Anyway, he said it didn't have enough power so he pulled the stock crossfire 350 and cut and pasted a big block into it. After replacing the windshield three times from the torque twisting the frame, he installed a newer 350 with just a little more power than the original.

You have to look at everything if you want big power. Don't know how much power the Jag can handle.