A couple of weeks ago I looked online to see what the rods looked like inside of a 4.2 liter XKR engine. I found a photo, but it was of a 4.2 rod sitting next to the rod from a 4.7 liter Aston Martin engine and a custom made rod that was put into a rebuilt AM engine. The photo was posted by a skilled engine builder named Pavel. The custom rod in the photo is designed for 900 hp levels.

I told Pavel about my plans to have another engine built at some point next year and that his high level of building interested me. He pointed out that the rods in our engines may be the limiting point when it comes to how much boost can be applied. I think that he said that they are made from a sintered or powdered metal vs. being forged.

An engine like Pavel describes below would cost around $18000 PLUS the cost of the engine being rebuilt.

I received an email from Pavel this morning about my interests in having him rebuild an engine for me so that I can explore higher boost levels:

"Hello Jeff,
Very nice to meet you. Thank you for the kid words you left in thread
on 6speedonline. I read through the post several times and you have
one incredible machine. After finishing the 4.7L Vantage engine I have
done more R&D with exciting news. I found a company willing to
manufacture engine sleeves. This allows any older Jaguar or AM engine
to be sleeved for thicker cylinder walls in the forced induction
applications as well as vary cylinder bore size from stock 86mm bore
all the way to 91mm. This can safely increase your displacement up to
almost 4.7L if you choose to go that route. My contact information is
listed below in the signature. If you have any question and want to
discuss further details please don't hesitate to email or call.
Regards,
Pavel"

Hmm... a 900 horsepower Jaguar XKR. THAT sounds like it could be WAY BITCHIN'!

I wonder what AVos would do with a 4.7 liter Jag engine (with beefed up internals) sitting in his garage?

If you look up "Pavels Racing Engines" on Facebook you can find him. I would post his phone and address here for you, but it didn't attach in his signature. I have his email address, though, and you can PM me if you'd like to have that.

This is the forum where I found Pavel. He has great photos from the Aston Martin engine rebuild and the photo of the rods is further down its page:
Vantage V8 4.7 engine rebuild - 6speedonline.com Forums

 

Thats a carillo rod, they, oliver or the company i used pauhter can all make custom rods if you send them the stocker. They can change boresizes on rods, shorten or lengthen. I spent $200/rod on mine. That rod should be able to handle 2000hp as mine and olivers are. So should carillo's unless thats a spec'd less expensive hipo rod. My opinion is there is never anything wrong with over spec'd parts for reliabilty. The engine should be studded too with arp studs instead of bolts as they clamp much better(you need that to keep the heads down and head gaskets in place on high boost apps) and since they dont torque into the block threads theres less danger of damage

 

Have read his posts before, great stuff. I have other plans for a 4.8 ltr engine at a lower budget than 18K, but that will only materialize if I can create a budget for it, or win a lottery ticket ;-)

 

Pavel Osovets, engine design specialist
Shop: 224-400-9569 | Direct: 847-732-7696
Alternate email: posovets [insert the at ] ( aa aaaa aaaaat )gmail [insert the dot] ( d aaaawt )com

Pavel's Racing Engines
950 N Rand Rd | Suite116 | Wauconda, IL 60084

 

Until there is a high performance set of tubular headers to allow the free flow of exhaust from all the improvements in cylinder displacement, compression and air induction, power gains will be restricted. The first and foremost, modification to a stock engine system should be the exhaust. Sure removing restrictive mufflers, restrictive catalytic converters, and faulty pipe bends is a start, but the most restrictive thing is that up-stream restriction called an exhaust manifold. Take a look at any engine from a performance marque, Porsche, Aston-Martin, Ferrari, Chevrolet, Viper or any other. What do the have in common? A well designed exhaust starting with a set of headers. A high performance Jaguar shouldn't have a passenger car exhaust. Some well known manufacturer should produce a set, after all you can get high performance headers for a Chevy Nova, why not a Jaguar XKR?

 

I think I have seen some "performance" exhaust manifold for the XK8/XKR but as I recall (1) they were very pricey (as is most stuff for these cars) and (2) they looked to be the same basic shape as the stock manifolds but in stainless steel rather than cast iron. A third consideration is that they are likely to be a bear to install.

Doug

 

Yes, an engine is essentially an air pump. The more air that it can pump, the more power that it can produce. Back in the Muscle Car days you could get very dramatic increases in power from a good set of headers.

I think that the reason that we don't see a lot of headers for XKs is the limited demand. Sure they would do a great job of increasing the air flow and power, but I suspect that the companies don't think that they would sell enough of them to make it worthwhile.

As has been stated, there probably are some, but the cost of them will be high and installing them, or having them installed would be quite a project.


----Index----
XK8's were not equiped with tubular exhaust headers.
XK8's were built with iron exhaust manifolds just like the ones found on American cars in the 1960's with cast iron V8 engines. So, why didn't XK8's come with tubular exhaust headers rather than the restrictive exhaust manifolds? Two reasons. First, since most of Jaguar's production is luxury 4 door sedans, and tubular exhaust headers do not absorb engine noise and vibration like iron exhaust manifolds do, so for luxury 4 door sedans, the iron log shaped exhaust manifolds were preferrable. The second reason is that Ford Motor Co. wanted Jaguar to be lower status than Aston Martin, which is why the Aston Martin with this engine does have tubular exhaust headers.

Performance modifications.
A set of tubular exhaust headers to replace the stock exhaust manifolds would give a big boost in performance. I don't know if the stock exhaust headers used on the Aston Martin V8 Vantage will fit the Jaguar XK8 chassis. A picture of these can be seen at;
2009 Aston Martin V8 Vantage Engine Cutaway Photo 8
The factory part numbers for these Aston Martin V8 Vantage exhaust headers are 6G33-5G236-BC for the right side and 6G33-5G232-BB for the left side and the factory prices are $1616.49 and $1432.55(prices correct in July 2008).

Replacing stock XK8 exhaust manifolds with headers

 

No doubt that you can improve the exhaust system, but considering what I can push out with just the sportcats, I think it’s a bit exaggerated as a holy grail. Bip has recently done some long tubes, yielding about 15 hp on a xjr with lower and upper pulleys (amongst others, on an eaton). So considering the price and yield, it’s onlyfor the ones where budget is of a lesser importance.

I wouldn’t go for 900 hp orso, although you can beef up the mb gearbox with ease, the rest of the drivetrain is not up to that job I guess, so more needs to be adjusted for these levels. For me it would be to have build an engine for once which is as efficient as possible (not overly strengthened, yet still with light components, strong enough for the job), and also lower boost pressures to drive (so less power consumption from the engine to drive the SC, meaning power to the wheels), yet still have a high power level (at least a little higher then now). Of course for some fun (with a simple upper pulley change if you have a TS kit) you could get lots more power. Have just run for testing purposes at about 24.5 psi (after I installed a water/meth kit) , pretty scare again ;-).

 

There is no reason i can think of why they wouldnt work. The same chassis configuration for yrs. But I also agree with Andre on the headers. A shorty set, cheaper and easy install would certainly be a better bang for the buck. And while you may get them in...what about when you have to do other work again sat motor mounts. ac/tranny lines?

 

There's always eBay... 08 Aston Martin V8 Vantage Left Driver Exhaust Header Manifold 6G33 5G232 BB | eBay