"The pistons are produced from cast or forged, high-temperature resistant aluminum silicon alloys." MAHLE North America | Aluminium pistons for gasoline engines

"To match the increased output and the increased mechanical and thermal stresses that supercharging imposes, the new XKR V8 has stronger pistons,forged from single billets of aluminium alloy. It also features oil jet cooling on the underside of the piston crowns, for maximum cooling and minimum distortion. " XK8 Lovers - Models

If you KNOW that 4.0 pistons are also forged ones please confirm this. Maybe Count Iblis would be the right man to tell this fact.
Count Iblis

 

Big bang?

Serioulsy hope not for you though, NOS just makes me nervous as it adds more complexity. Take carefull steps I would say, and keep measuring...


Count Iblis should indeed know about the engine details.

The 4.0 documentation only mentions that the rods are forged (sintered), no mention of crank or piston being forged. The 4.2 documention is specific and speaks about forged rod, crank and pistons. Considering how I've beaten my engine, there must be some truth in the latter.

 

Given I just got the car together with lots of changes, I intend on going slowly in the testing phase as I want to still be able to enjoy it for the rest of the lovely summer and fall months here.

I think being able to add fuel via a simple additional fuel jet injection with whatever amount of additional fuel I want, without having to try to force so much more through the stock injectors is actually simpler and safer than what lots of people with the twin screws are doing, given the serious problems some have had lately.

 

Steve M just proved the 1999 4.0 is well up to the task of running an 11 second 1/4 mile. Period.

Could it handle 150+, maybe, maybe not, and we may never know since my goal of being able to run an 11.99 may only require a 75 or 100 shot of Nitrous on top of the power I already have. It is not my intention to keep upping the power until it blows up, just enough to know I can run an 11.99. I do not believe it will take more than a +100 shot to get there.

I am going to run my car on the dyno with the +50 and +75 to see what I get, then run it at the track for a real world test as dynos, while a good basis for tuning and comparison with the same dyno, are not the same as a real world performance of a 1/4 mile. If I find I need the +100 to break into the 11's I can make the decision to put in the +100 jets or not, depending on how I feel at the time.

 

I can't see any post that is saying/suggesting that you can't get similar or more hp than with a twin-screw kit (that would be silly as well), besides kyle04 who wonders if the drivetrain can hold up, but he doesn't have 2 million HP or?

I do see, (including my post) people concerned about using NOS, and no one is saying you shouldn't do it, other then that you should be carefull.

Of course I agree with SeanB, measure 1st so you know where you are, and just as important, use that to check everything is ok, so you can take carefull/controlled steps forwards to your goals whatever that may be.

 

Now if I can just get this Nitrous controller to work.....I'll see if I can get to the #2 spot on the list

 

[QUOTE=WaterDragon;814979]Now if I can just get this Nitrous controller to work.....I'll see if I can get to the #2 spot on the list [/QUOT

So, you gonna run under 11.924 ?

 

Gonna try for between 11.924 and 12.25 for the #2 or #3 spot. If I am able to pull an 11.99, all the better. I'd be happy with #2 or 3.

I should have clarified I was gunning for the #2 or #3 "jaguar powered" spot on the list.

 

How about me?

 

No worries my Jaguar brother, I think we both know that as soon as you get in an honest run at a good track, now that your O2 sensor is fixed, you WILL then join the exclusive 11 second club.

I don't need to be the fastest on the list, but for me to make it into the 11's would feel like an automotive achievement.

 

NP, brother. I am cooking snake soup at the moment. You will see....

 

Snake soup? Really? What kind of snake?

Does that make you "potent" ? heh


And I am hoping the positions on the list are dynamic, that people keep improving so we get more forum members in the low 13's and 12's, and even a few more in the 11's. Where are all the XKR twin screw cars? Avos, yours ought to be #1 on the list since you are pushing well over 600 HP and you have the LSD, why not have a go at a track? Come on guys, join the fun!

 

For less money than you might end up spending, I went and bought me a Jaguar that should be in the low 12s and will do good lap times too. But I still love driving my XJR!

 

Whadya get?!
What did you get?!

Do tell

Inquiring minds want to know.



I did pretty well on this one,a 2000 XJR, I only paid $8,300 for the car 3 months ago with 55K miles and it looks like it was never sat in. It has only been driven in the rain 4 times since new and lived in a very nice garage with a pampering owner.

Only one small ding on one door which I will have removed when I'm done with all the mechanical fixes/upgrades.

 

What's the best way to launch a stock 1999 XJR? I'd love to put my money where my mouth is, and humiliate my M3 and Camaro owning friends at the dragstrip. First, of course, I need to get my feline running properly again. She hasn't been the same since I had the fuel pumps replaced... :-(

 

Very powerful snake soup.

Jeff in Tucson will show what TS powered 4.2 XKR can do. Waiting for his 1/4 results later this year.

 

Are you sure that both pumps are working? That is to be known #1.

As for launching, my 2002 XJR's traction control was not as good as my 2000 XJRs as I can just stab the gas and go in my 2000, but the 2002 would fall on it's face, pause, then go. If yours does not stutter or pull power, then leaving the traction control on and firmly rolling into the throttle is the way to go, otherwise, it is TRAC off and good tires for the fastest launch.

Are you game for making any small mods?
Just by adding an additional 2" intake into my stock airbox gave an improvement for my '02, I think the stock snorkel to the fender is a little restrictive, even on the stock motors.
The next $99 well spent is to have your TB Maxbored from 75mm to 82mm. It bolts back on the car as if it was stock, and you cannot tell from the outside it was ever improved.
Of course, nothing beats adding a pulley. The upper pulley is the cheapest.
I've recently heard very good things about Steigmiers snake bite kit for the Eaton where he re gears them internally, so you use your stock pulleys and get a lot more boost (+4 lbs ish) Few things make power like adding boost.

 

"Jeff in Tucson will show what TS powered 4.2 XKR can do. Waiting for his 1/4 results later this year."

This is why I'm not claiming I'll get or keep the #1 spot with my 4100 lb or 4200 lbs with what I usually carry in my trunk, comfortable sleeper saloon, these 4.2s like AVOS's or JgaXKR's or Jeff's running high boost, meth, with LSDs ought to be at the top of the list.

Sure I could try and maybe succeed in being "the fastest" with the help of a few larger Nitrous jet sizes, but then I would be a little worried about blowing something up, and then it would no longer be fun, just competitive, so I will be quite content at the #2 or 3 spot on the current list. If more of the big boys start getting to the track and I get bumped down that list, I will still sleep well at night. Right now I'm having lots of fun with the car, so I want to keep it that way

These guys don't really need a track, just take a video with your phone of a 0-100 run and we can compare those- unless your "yella" as they say in Texas. There is no excuse not to show what ya got via phone video.

Where you are depends on where you came from, only a year ago I was asking how to remove a valve cover...

 

Stop making me think about nitrous

 

I just had both fuel pumps and the lines from the tank replaced, and I am now smelling raw gas, especially under hard throttle. My gas mileage has dropped by 4-5 MPH, and the car idles and runs perfect until you hit about 1/2 to 3/4 throttle, after which it falls flat on its face and then leaps forward with full power. The exhaust seems to have a different odor, also. I hope my convertors didn't get ruined when the shop repeatedly cycled the key to check the pumps. I also notice that the fuel filler door doesn't quite close, as it now contacts the gas cap.

I would love to add some mods after the XJR is paid off. Right now, I can barely afford to keep it and my wife's van on the road. Thank God I work at a parts store! Lol.