I did the mitsubishi because they are plentiful here in Aus - especially if you use the 16G compressor on the TD04 turbine, this will give a faster spool. Only thing to be careful of here is compressor surge as the turbo might spool too fast compressing more air than the V12 can handle at lower RPM.

The maps I posted were based on air flow preditctions at around 500hp.

I can buy a TD04 for under $100 from the WRX guys who have upgraded. Also APS here in Aus have a twin turbo setup for the LS1 using Mitsubishi turbos and it spools mighty quick. I'll see if I can find the article.

 

fair enough warren, that set up, 16g comp. with the smaller td04 turbine, does make more sense, but you then are getting into a hybrid turbo! that can change costs.

steve,, remember most XJS have automatic trans, so finding the turbo sweet spot can be a little interesting, manual you can drop into a gear where you know it can boost quickly.

warren, compressor surge is way over rated, have built many, that the guys actually like the rump-rump surge sound, never lost a turbo, surge worries are more for constant rpm when turb is held in the surge zone for long periods of time.

and here in USA, many LS series have been turbod, an LS 5.3 has much more exhaust energy than a jag 5.3. exhaust energy is what spins the turbine.

and anyway, i personally like a lot of torque, early, especially for a street car, i just dont race much past 100mph, i'm all about acceleration, and getting it over with.

but to each his own!

and i'm still waiting to see M90s twin turbo, hehe!

couple pix , small one is garrett, equal to a 12g mitsu, mounted on a 1.8 Isuzu, and it takes a while to come on boost, but great top end,just where I dont need it!!
other one is for a 2011 nissan GTR, one side, notice how small the turbine hos, is compared to comp.hsin.
car made 850WHP, yup it was quick.

 

that nissan hybrid turbo cost $2400. usd, each.

steve ever tried to brake/boost an automatic, with a lazy turb?

 

I do tend to agree Ron, I am not looking for a ***** to wall racer. I really like PD supercharger but dont want the complexity and weight of 2 M90s on the front, and I do not think there is any way I can fit a single supercharger in the V or anywhere else in the engine bay for that matter.

I have researched the F1 turbos and they used to run quite small turbine housings with massive compressors and then use a very LARGE wastegate to bypassed exhaust gas this 1) controled boost creep and 2) reduced exhaust back pressure up top.

This is what I ws thinking - 2 stock TD04's from a WRX/Volvo/Saab, I can upgrade the compressor housing later. As I said I can pick up 2 of these for around $60 each in good condition and the upgraded 16g compressor housing and wheel for $150 each, there are so many on the second hand market here as the Subaru WRX is plentiful. The Mitsubishi also come standard with WC bearings, this is a must have. The cheapest I can get a T28 is around $400 each.

I had a Subaru WRX with the TD04 and the 2.0L struggled above 5500rpm, not enough compressor flow, the Volvo V70 T5 also has this turbo with a 16G compressor which was a much better deal on the 2.3L. I only used the TD05's as I could not find a TD04 16G and 20G map.

Why I was concerned about suge was that have seen a Toyota Supra detonate a turbo in under 30seconds on a dyno due to surge.

 

a V mounted m90 wouldnt do you much good on this car. mostly because of how hot the V12 runs, and partly because of how hot the Delta temperature on an intake mounted m90 tend to get. you could get down a few pulley sizes but that would just make deltas hotter.

 

The 2 M90 's would not be V mounted but side mounted on the manifolds. One M90 would be too small, I was referring to one V mounted Whipple.

I was driving home tonight and I do like the instant response from the M90 (on my daily).

 

Hi Ian,
Oddly enough, I plan to do exactly what you have in mind on my V12 test stand in order to avoid all of the complexity required with the FI setup. I only want to run an engine with some of the mods I do in order to check things out before installing in a car. A couple years back, there was a person on ebay who actually made some very good looking intake manifolds for two four barrel carbs for the 5.3L V12. My issue with the set up was the smallest carbs available are the 450 cfm Holley which would total 900 cfm. The engine would have to be highly modified to run well with that much carb and driveability may be iffy on the street. I have a friend with a cobra replica which has a highly modified 351C with a Holley Dominator which is around 1000cfm and at any other mode other than WOT, you could run a Ford Pinto on the exhaust. A couple of Holley two barrels might be more appropriate. The hood clearance is almost nonexistent above the manifolds, a couple of bulges will cure that. Be advised I'm not an hp engine builder, just offering things I've come across.

Well, I'll be darned. Look what I found, Jaguar V12 Dual Quad Intake Manifold XJ12 XJS | eBay

 

those intakes are rediculously expensive. i was so close to buying one, but if im gonna cut a hole in my bonnet, i want a blower sticking out of it. not a carb.

anywho, the V12 is only drawing about 500-600 CFM at 6k RPM. Those manifolds are designed for bored over stroked out V12 speed boats.

im feeling pretty good about the new motor. with my blower combo and mods, ive got an effective displacement of about 6.2 Liters and 13:1 compression at WOT on a 3.4" pulley and headers. power is going to be on par with a good running V12 but about 300lbs lighter in the front. also since because mid engined!

 

So your twin turbo project evolved into double screwed one? Is it running yet?

 

My twin twin (LOL) compressor project is still in the planning stage, I have two smaller jobs to complete first.

However, if it turns out the damaged 12 is beyond recovery the block will end up as a coffee table. One option is then to use the HE 12 in the XJ-S but I get differing views on suitability. Some maintain it is no good at all while others say it can easily be good for 700HP. I am still looking for about 450HP and good driveability. The route would be to replace the stock pistons with (possibly US spec) pre-HE pistons. Beyond that it would remain pretty much stock except fuel and spark. The current plan is still Megasquirt and wasted spark.

So how (un?) suitable is really the HE? I can guess that with supercharging the air/fuel charge will be dense enough to give the normal ignition system problems under certain conditions, but a modern powerful wasted spark system "should" sort that out? Ideally I would of course prefer coil on plug but even with a more compact Sanden compressor lifted a wee bit that is really not feasible.

Thoughts gentlemen?

 

if you wanna talk to somebody about a good running flathea, get Ronbros on the phone.

hes running bigger cams, bigger valves, and higher compression flathead pistons.

 

Ever consider a V8 swap? An LS2 with a cam and a tune would probably get you up to about 450hp. It's a reliable option, but admittedly it's not very "Jaguar" and not for everyone.

 

if you were talking to me, im not crazy about the way a V8 sounds, TBH. or the V8 tuner scene. i like F.I. 6 cylinders.

 

I meant that for Per - should have quoted his question.

The supercharged 3800 does have a nice sound BTW. This is going to sound strange but I think I like the sound of the engine heard inside the car more than the exhaust note.

 

mostly i like the blower whine.

 

Yea, maybe that's what I like about it. I hope mine sounds like that!

 

With FI the HE is not so bad, if you look at the valve size of the V12 they flow about the same as a 350 chev 2.02/1.60 inlet/exhaust per cylinder. The V12 valves are 1.62/1.35 for ALL V12s pre HE all the way to 6.0L.

I think 500HP from a turbo HE would be possible with modern EFI and minimal mods. Drop CR to 9.0:1. You could use a de-compression plate although I am not a fan of these as they reduce the squish area. I would look at removing some metal from around the valves to deshroud both exhaust and to a lesser extent inlet. Remove enough to set the CR at 9:1.

I don't think you need to go to the expense of COP (coil on plug) a good distributorless system would be good enough, MS have coil packs and ignition drivers. You can install the ignition drivers in a remote box to drive the V12, so you don't even need to go EDIS.

 

ya know, i was just wondering the other day what it is about a 5.3 that makes such an incredible induction noise (growl) compared to other engines (especially american) that make an annoying sucking gargling noise instead.

is it the really long intake runners in the heads? is it the intakes? is it the twin TB's?

 

According to a friend who is an SAE engineer, each engine has a distinctive induction sound based on all of the things you mentioned. According to him, tuning the intake side is literally a matter of acoustics, like tuning a musical instrument.

 

why on earth didnt you throw the 455 in the xjs. so much power there.