Bleh...said the engine

then Bug-a-dy bug-ady rattle rattle

 

20PSI is not a problem with stock internals. In think you mean 23PSI++ ? There are a few piston manufacturers, which have done forged ones for 4.0 XJRs. Lead time a few months. Conrods can be ordered from many manufacturers. Lead time a few weeks. Then you need bigger injectors, stronger valve springs...etc. etc.

Why not go for 4.2 ?

 

Sure, I would consider a 4.2

And, yes, 23++lbs.

 

Here is a thread that might be of interest:
https://www.jaguarforums.com/forum/x...st-pics-87047/

For the internals, I suspect you will be in complete custom territory. Not to say it couldn't be done, as there are plenty of places that can make custom rods, etc, but it won't be cheap.

There are a few members (Avos, JaXKR) who have been running in that boost range for some time now and I don't *think* they have done a lot of bottom end work to get there.

If you look at the pics in that tear down thread the bottom of these motors is already built like a brick sh*thouse, what with the full skirt for the main bearings and all. The 4.2 has a few improvements as well as a little more displacement and would be a drop in for your 4.0. Jeff in Tucson just replaced hi aickly 4.0 with a 4.2 in conjunction with a Twin screw setup.

Good luck, should be an interesting journey.

 

Oh, well 23++ is a little different.

Can't wait to see what you build for this little project.

 

Yes, I think the 4.2 build would make sense. My thoughts are, if I'm really going to build a motor for big power, I might as well make it reallllly strong and then be able to run more boost than the stock engines were designed to handle.

I will be in custom territory somewhat, but, as you know, it can all be done if I'm willing to pay for it. It will take me some time to think about what I want to do:

A: Build the Jag to be the highest HP XJR/XJR ever built,
-or-
B: Keep the Jag mostly stock with the eaton and spend my car toy money on something like this:
http://cgi.ebay.com/ebaymotors/Rare-...ht_1948wt_1165

or this http://bringatrailer.com/2011/09/25/...ster-miata-v8/

At the moment I am still leaning heavily toward the Lotus, but I think it is worth researching what would be involved to do this right with the Jag.


In the meantime I'm going to use my relatively stock engine and keep my XJR as a daily driver.

 

I believe Avos said in some post he ran the 20 lb pulley and race fuel only for the dyno, but runs much lower boost normally and JgaXKR told me he is running 12 lbs. Please correct me if I'm wrong (again ; )

If I go this route, I would want to be sure to have forged ceramic coated pistons, forged rods, upgraded everything I could for more longevity and peace of mind.

 

After much discussion, the "house" decision is to keep the Jag as simple, and later buy some 2 seater lightweight toy my fast street/track car.

News flash, Now I'm thinking about buying a V8 Miata instead as I already have an nice relaxing Jag which I really like for just cruising or road trips.
I think this would be a better fit for me than the Lotus, as I like cars that don't attract too much attention, but are surprisingly fast.

XKR look fast
Lotus looks fast
Miata-insane handling, even with the V8, and few suspect its potential performance, Did I mention V8 ? 5 liters, 300-400 RWHP is not to difficult or expensive to achieve, and only 2500 lbs

 

Sounds like it's already sorted, but just for fun:
How to build the best AJ33 possible:

Step #1 - IGNORE CONVENTION!!!

Step #2 - Start with the right parts.....

RSR Performance Casting: 357 T-6 aluminum - HIP'd
Increased Deck and Cylinder Bore wall thickness

Updated Oiling / Cooling path

Billet Aluminum Sump - made from a forged reduction of 6061-T6


Billet Crankshaft

Carrillo Rod / JE piston

CNC Cylinder Head

Steel Head Gasket


Step #3 - build a test engine


Step #4 - Dyno, Dyno, Dyno, and then Dyno some more.


Step #5 - Win Races



Hope this helps.

 

Anddddd how much is that engine? I am thinking more than what I paid for my car!

 

Since all design and machining was done in-house at RSR, its not astronomical.

Full dress engine is around $35k - no electronics
Price comes down substantially without the ITB induction.

And wasn't this the point?
If you were going to build an engine to handle "lots" and lots of boost, say 20 lbs of boost from a KB twin screw, what parts would you use? Crank, rods, pistons, etc. etc. We're talking a "take no prisoners", "there's a new sheriff in town" kind of bottom end.


Regards,

The Sheriff

 

WoW !

 

Holy Cow, That is the baddest *** Jag motor I've seen! But I must admit, I was not thinking about spending $35K on the engine for my $15,000 XJR though. That work of art belongs unrestrained, free to run the raceways! Not cooped up in a street car.

 

Watching this with interest as I am building a competition car with the 4.2 SC

 

On my v6 nissan build in the truck with ken bell twin screw, i went to pauhter billet rods, cp forged pistons(coat the top but forget about skirts, its a waste of money on a street engine as the coating will be off the skirts in a few k) and total seal gapless top rings. That setup ran about $3k for custom. That works out to about $500 a hole. Stock crank in a bedplate is pretty damn strong stock. Since youre boosting dont spend money on anything other than reliabilty and getting it running. Great valve job and clean ports and thats it. A turn of the boost quickly builds power like nothing else can. Theres nothing as satisfying (imo) than building stuff thats not on the shelf and not other easily duplicated with a mastercard and cell phone