and when the special heads went onto a 7L engine 44 finally made 650-700hp, but did say they were not very reliable engines. some talk of 700+ engines in UK , and we shall know more of the story, when Allen Scott gets the latest book out.

and then Jag dissolved grp44 relations, stopped the money, jag gave all later money to TWR of UK, and they went on into Grp C cars and engines, rest is history.

Tom W. did a fine job of promoting his company, and made great contributions to motoracing,.

NOW to change the subject a little!

if you guys that are building an engine to Group A specs, it will be an already 30+ year old design, so 500hp just maybe could be done(maybe).
you are not using very little if any modern developments, what will be different in your engine compared to a 1984 Grp A engine?

 

I think I am going to end up FI SFSC where the PS pump lives. I am not looking to build for outright HP I want a torque monster engine. FI overcomes some of the problems with the intake and head limitations.

A very light port, mostly just cleaning up and matching of intake and exhaust. Possible enlarge the valve seat area (if there is enough meat in the seat) so its around 86% of the valve diameter, and recut the seats to 3 angle.

I have not removed the heads from 6.0L yet. I need to get the car re-assembled and registered once this is done then I will strip my spare engine.

 

with my motor I have done a lot of things that may have not been done by group a, for 1 the quench height is .050 thousandth, which is the ideal quench.

forged aluminum pistons with the dish centered around the sparkplugs with two valve pockets

cams with .440 and 278 advertised duration

the heads have been ported to full gasket match
and consistency. the exhaust didn't really need.to be opened up seeing as they were larger than the gasket inside.

 

I asked this question before, but the answer wasn't exactly clear. Can a stock 5.3 HE handle twin turbos with low boost? I believe the current compression is 11.5:1.
Would there be any significant performance from doing so?
There are enough cars with turbos nowadays that finding a set from a 4 cylinder in a junkyard shouldn't be too difficult or expensive for experimental purposes.

 

11.5 is probably too high for pump fuel. If you can avoid detonation you may be able run very low boost. Water/Meth injection may help here.

What I would do is add the turbos and run say 1 psi boost. You will need to make a knock detector, part 2 of this Autospeed article has a very simple diy detonation detector with headphones.

AutoSpeed - DIY Detonation Detection - Part 1

If knock is present with say 2-3 psi then lower CR is needed. easiest way is to use a copper headgasket, 10:1 might be ok for low boost, but it will be trial and error. I also think it will need programmable ignition to get the advance curve right for the boost and high CR.

 

Perfect! Just what I was looking for!

 

jamey, google remote turbo systems, STS is a good company, they can sell you parts to make a simple twin turb. setup,remote mount its just pipes running back and forth, much simpler and CHEAPER than any other forced induction system.

good idea to use some small turbos from 4cyl. car, dont forget you are not going to build a *****-out super-duper go-fast engine, you should be just wanting,say 5-10 psig at full throttle, cruise will register a vacuum(good for mpg). for a stock used engine, i'm sure it will work, been there,done that.

most of what talk I about is REAL, not all types of numbers and theory ideas, with no actual hands on experience.

you will need gages, for manifold readings of boost and vac., fuel pressure at full boost.
all basic simple stuff, R&D turbo related sites on line, there must be hundreds out there now a days.

i been doing turbo cars & trucks since 1979, and the cheapest way for regular street car is rear remotes.
pic of my Opel diesel turbo setup, works great and has reasonable power without blowing it up, better mpg ,done it back in 2007!

sorry dont have many pix of others i have done!

 

Turbo playing will have to wait a little while. My daily driver just bit the dirt so I'm on the hunt for a new one.

 

I'm still confused as to where under the car you'd mount thoes turbos, because having to build 8 feet of 10 psi would give you turbo lag that would.be uncontrollably long.

the camaro race car.I had made 10psI on 350 cubic imch 9:1 was ridiculously bad with the lag, and it makes it a chore to drive aggressively, especially if yhe backend was out.

that's why I chose NOT to.go turbo on my car, because it's never as nice.to drive as a.well built naturally aspirated engine.

 

I know what you mean. In about 1989 I had a locally made GM (Holden) car with a Nissan 3.0L I6 turbo, I had modified the car for club racing and it made about 500hp at 19psi, BUT it was like driving with a switch if you below 4000rpm. Made it very difficult to drive on the road in the Wet.

I do like the idea of rear mount turbos on a large high CR engine but I don't think there is enough room for pipes under the car.

 

It doesn't have to be that bad! There are a number of design elements you can use to mitigate turbo lag, especially when you're not trying to ring every last HP out of the setup. An intelligently designed 5.3L engine + turbo setup certainly does not have to suffer from really bad lag, though I don't think you can totally eliminate it. A properly sized turbo, properly sized piping and intercooler, shortest piping runs as possible, etc... these can all be used to mitigate lag.

You guys with V12s are brave to even consider this. I've seen those engine bays, and it seems like it would be really tough to fit a turbo + all that piping under the hood!

 

I pretty sure calvin's car is a manual transmission, turbos and manuals are not ideal as a driver's car. When you let off the go pedal to shift gears the turbo's spool down a bit and the engine gets flat. It's like one second you're driving a low compression econo box from the 70's and then two seconds later your back to a hi performance machine. I've driven well engineered modern cars like this. Its novel at first because the turbo kick is exhilarating but after the novelty wears off then its unrewarding and annoying to drive. Turbo's are a great way to squeeze peak HP from an engine but that's about it. To get the drivability right the turbo's would have to be very small and re-circulating valves would need to be installed and this would further complicate an already difficult install and then you get to diminishing returns from the smallish turbos.

I think Calvin is on the right track by building the largest displacement motor he can afford and making it breath well. With the right rear end gear and manual transmission its going to be one great driver, even if it doesn't get to 500hp as a specific power. Let's face it...the other V12 with a manual that makes 400+ HP has a prancing horse on the hood and Calvin's Jag will ride far better and handle almost as well.

 

thanks ICSamerica,
my girlfriend's 911 used to be like that. go from a geo prism missing on one cylinder to a top fuel car in an instant.

also, jag v12s have a complicated enough oiling system that I don't want to plumb in two turbos aswell.

turbos are a nice novelty and are great when you want to extract as much power as possible on a budget. but having driven switched a motor from turbos to superchargers, I prefer the later way more.

if I were to pick id go with a centrifugal supercharger because they have the least noticble affect when it comes to throttle response.

but not for nothing there is no displacement for.cubic inches that doesn't come with a drawback.

if I could, id build a motor that was 7.3 liters. becaus its much easier to make 1hp/cI which would give me 450 vs the 400 I have.

more displacement pulls harder on.the intake ports creating more suction, which inturn makes more cfm flow from the heads. since each rotation it's creating more displacement.

more displacement also makes more torque and shifts my power band.lower, where it's more useful on the street.

 

Okay, getting my flamethrower out on this one. If you are making power that is in excess of 1 HP per cubic inch, you can eliminate most of turbo lag and near 1.6 HP per CI you can eliminate it all together. FastKat statement rings true and seriously there are a lot of armchair racing going on this thread <---It reminds me of this from posts of people that have not ran built TT and SC cars and “read” this or that or heard some story from another person. Sure, put a set of TT on anything stock and nothing else and you will get lag and lots of it. I'm amazed reading some of these posts here-it is like we need to put a prerequisite up of building a higher HP car to eliminate pontificating as an expert. None of this is hard, in fact it is pretty simple and going turbo, TT, or a myriad of SC is not hard either to install and make power. Sure you have to relocate things, maybe make a manifold, fuel rails, et cetera that is what it will take and this is all normal. You will need a fuel system that can support your needs, space under the bonnet is an issue but again none of this is hard. Parts not available is going to be the tune of the day. What about when you make the HP, when then? Will the Jag motor hold up? If not, to me this is all moot, but seriously on pump 93 you should be able to make 700 RWHP if you have some time, money and you know how to do it but again you will need internals from pistons, rods, main caps that hold up. Personally I am only purchasing or thinking of building 1000+ RWHP on 93 pump at this time in my life so not behind my keyboard slamming keys talking about it. Hell even my one boat I am thinking of putting puffers on my motors as it needs to break 100 MPH. This whole challenge will be what is the mission long term, make power on pump and keep it drivable and then quantify drivable, at what cost and what longevity? Throwing a Paxton on a mildly modded engine is a lot of lag as a Paxton will act much like a turbo due to the Paxton’s design. Anyhow, thanks FastKat for a great post and glad to see some are on point here with experience.

 

agree, agree, agree, i'm still waiting on the actual 500hp Jag V12, this stuff has been going on for a last 2yrs.

there was someone else who talked a twin-turbo, V12 , never came to pass! dissappeared in the ethers of the net.

i'm sure viper knows his stuff, he also has more at his disposal.
he will find most on here, dont have the resources for 1000hp cars.
1000hp engine without the drivetrain to put it down, would be futile.

i cant imagine how the guys with 2000hp cars do what they do, and just yesturday some talked about a 3000hp car. thats nuts on the street(but fun)!
like chuck berry said ,justa slippin& a slidin all over the place. hehe.

will the stock Jag drive and suspension hold 500hp,much less 1K hp?

before all is said and done,a lot of money will be spent! its a never ending project.

 

I'm thinking if someone one wanted to get to that HP level with turbos it would be a whole lot easier to TT a LS1 or SBC. The turbos and traction upgrades necessary would change the nature of the car so much that a Chevy conversion is a logical and acceptable step. With a SBC conversion there would be plenty of room for the turbo plumbing & intercoolers. Fuel systems are available, proper head gaskets are available, turbo manifolds are available and 700HP on a 383 is basically a starting point. It difficult to get stock turbo engines to live if they're boost is upgraded. I don't think the Jaguar V12 with it's open deck block would live too long with the amount of boost necessary to make it worth doing.

 

It all fine for you guys who have 50years experience building HIPO cars, some of us have 30 years experience in electronics, for me it's about learning how to make power form an engine efficiently before I go spending $$$$$ and getting it wrong.

Please share your experience BUT don't shoot down those of us that are interested in learning.

 

Guys, the manhood measuring has got to stop.

in my buddies shop we have an expression:
"people talk about how much experience they have, only after they have run out of knowledge"

TT a jaguar V12 in the stock engine bay for a drivable platform with 500 hp is just impratical.

even if you were to make 1.0 hp per CU before boost, you'd be running 12 to 1 compression at least before the boost hit because that would require 326hp. you'd have compressor lock and you'd blow the heads right out of the block. I've seen that happen on aluminum blocks running too high compression. Not to mention if you tuning wasn't bang on at that high compression, you'd burn the daylights out of your pistons.

if i made that magical 1.6 hp per cubic inch id be making 521 hp. why would i add turbos? It's car i drive to college and back in.

i understand that boost is this obsession, but i can't tell you how many times i see guys crank up the boost on their cars and all of a sudden their lap times go down because guys build for numbers rather than practicality.

At work i hear a lot of stories of "i bought these garret turbos and 30k later the motor made 800hp" Anybody who pays enough money can get anything they want done. Has anyone else seen the rockets in the back of minivans?

It's cool if you can afford a dodge viper or a few dodge vipers and you want to make 1000 hp, using the highest quality components and electronics. but the rest of the free world doesn't have those luxuries. So we plan, and over plan, and plan some more and calculate all the costs/benifits/drawbacks of what we plan on doing. just like warren said.

Oh, and my motor is already built. I'm just waiting on oversized valve shims. before i can finish putting the heads on. it has a crank stroked to 74.5mm Rob beere overized liners 96mm, Ross forged pistons, Isky XM5 cams. Manley Sportsman rods that have been narrowed 30 thousandths on one side, and 70 on the other. Chevy 229 v6 bearings. total seal rings.

and it will not have turbos or a supercharger (maybe supercharger eventually)

 

Whilst turbos etc are fun, I have to agree that seeing someone take the v12 and see what they do NA is very exciting. Looking forward to seeing the end result of calvin's engine build in terms not just of the KW and NM numbers but driveablility.

 

Well as I have said before, I have seen Blue Dorward's TWR that he built himself when he worked for TWR.
It is 6.4 litres. std cams. many Group A specs. Getrag 5 speed manual.
410 bhp, 405 lb-ft.
175 mph
0-60 in 5 secs
personally that'd be enough for me.

I was chewing the fat with him today when I should have been at work.. I asked him about turbo'ing, going for 500bhp etc.
He thinks any more that 400bhp and the cam buckets will fail, drive train wont cope, etc.

I am not knocking anyone's efforts to extract more power. I have done it myself in small budget ways on most cars I have owned, and I am tinkering with my X300. But I don't own an XJS so in this instance I plead guilty to being an internet racer!

I am aiming, one day, for a late 6 litre XJS.
I will want to warm it up. I don't know how far I would go, but think I would start by aiming for about 350-360 bhp with good mid-range drivability and I would hope using the 'full house' of AJ6 Engineering bolt-on gear would achieve this. I would stick with the GM 4 speed box for a while and see how it goes.
After that, maybe aim for 400 bhp and a manual box, but that will be spending more $$ and may not be an option.

In the end, an XJS is a 40 year old design, and there are many 'off the shelf' cars now that can muster 500+ hp out of the box.
I have driven a 560hp SLS AMG and while it was awesome it wasn't as powerful as I thought 560 bhp would be!
So in the end, for me, a damn' grunty street-friendly XJS would do it, and absolute numbers are probably secondary.