XJ XJ8 / XJR ( X308 ) 1997 - 2003

X308 1/4mile target 10.9

 
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Old 04-14-2017, 12:47 PM
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Default X308 1/4mile target 10.9

The current set-up should have right parts to do it but needs careful tuning
before any longer WOTs. Today found better MAF tune not to be at too rich or lean side. When that's fine then change from 3" upper pulley down to 2.75" and if still 100% confidence then down to 2.5" and fuel change to E85 or/and water/methanol injection. The minimum target is to go one second faster than car went with old, more stock style engine four years ago. ET was 12.34, so anything slower than 11.34 is disappointment. Cheers.
 
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Old 04-14-2017, 08:12 PM
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What was your differential gear ratio again? Wasn't it 3.54 or something like that? Have you had your car dyno tested (or rolling road?) yet? If so, what was the power output? Being patient and thinking logically with achieving your goal is a must. So when I used to drag race my Grand National 14 years ago, I would make minor changes so if what I was doing worked or not. Eventually I had the engine and transmission rebuilt but didn't take it to its absolute limit since I drove it on the street.
With slicks, my best times were:
60' was 1.53,
1/8th mile 7.29 @ 94.69 mph
1/4 mile time 11.53 @ 112 mph
Ran the 11.53 flat out one time since I needed a roll cage and was denied another pass. This was on a welter weight t top car with power seats (nothing lightened) that was about 3800 lbs.

I wish you the best of luck on your goal time. Don't expect to see a 11.34 overnight. But who knows, I could be wrong!
 
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Old 04-16-2017, 04:57 AM
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Marginal gains! Good luck with the target - it's a journey
 
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Old 04-16-2017, 09:50 AM
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Originally Posted by Sean B View Post
Marginal gains! Good luck with the target - it's a journey
The difference between 12.34 X308 and 10.99 X308 is about 160-170bhp and 220ft cap at the finish line .... So, very marginal gains
 
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Old 04-16-2017, 12:22 PM
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I should have asked first, are you attempting the sub 11 on your initial runs on the pulley swaps - that's marginal, lol I forgot - you're running an Avos kit with TS unit? How big?
 
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Old 04-16-2017, 02:08 PM
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Originally Posted by Sean B View Post
I should have asked first, are you attempting the sub 11 on your initial runs on the pulley swaps - that's marginal, lol I forgot - you're running an Avos kit with TS unit? How big?
Heaton is for boys, as well as 4.0/4.2
 
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Old 04-17-2017, 06:25 AM
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Originally Posted by Addicted2boost View Post
What was your differential gear ratio again? Wasn't it 3.54 or something like that? Have you had your car dyno tested (or rolling road?) yet? If so, what was the power output? Being patient and thinking logically with achieving your goal is a must. So when I used to drag race my Grand National 14 years ago, I would make minor changes so if what I was doing worked or not. Eventually I had the engine and transmission rebuilt but didn't take it to its absolute limit since I drove it on the street.
With slicks, my best times were:
60' was 1.53,
1/8th mile 7.29 @ 94.69 mph
1/4 mile time 11.53 @ 112 mph
Ran the 11.53 flat out one time since I needed a roll cage and was denied another pass. This was on a welter weight t top car with power seats (nothing lightened) that was about 3800 lbs.

I wish you the best of luck on your goal time. Don't expect to see a 11.34 overnight. But who knows, I could be wrong!
The new diff ratio is 3.58. You had pretty fast 60ft, like a high 9 car, but trap speed was quite low, like a car with ET 12.5...
 

Last edited by XJR-99; 04-17-2017 at 06:36 AM.
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Old 04-17-2017, 07:52 AM
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So I'm guessing here - a 2.1L Kenne Bell or Whipple? And you're running either a range rover 4.4 or Jag 5L? Most interesting if I'm right - or something else? No need to be coy secret squirrel!
Let's have the mods! - If I remember right, you blew the last unit?
 
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Old 04-18-2017, 05:53 AM
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Sami,
The one time I had a full 1/4 mile pass, about 3/4ths the way down the track it fell flat on its face because it was running out of fuel. I probably needed either more fuel in the tank or a windage tray. Anyways, I let up on the throttle and got back into it again to let the fuel slosh forward in the tank.
 
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Old 04-18-2017, 07:04 AM
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subscribed !
 
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Old 04-18-2017, 08:33 AM
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Originally Posted by Addicted2boost View Post
Sami,
The one time I had a full 1/4 mile pass, about 3/4ths the way down the track it fell flat on its face because it was running out of fuel. I probably needed either more fuel in the tank or a windage tray. Anyways, I let up on the throttle and got back into it again to let the fuel slosh forward in the tank.
Solid 10sec GN.
 
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Old 04-18-2017, 04:37 PM
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Originally Posted by Datsports View Post
subscribed !
no this one - https://www.jaguarforums.com/forum/x...2016-a-153266/

@ Sami, sorry for the ignorance - hadn't seen your thread. I hope you smash it
 
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Old 04-26-2017, 10:33 AM
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Today first time E85 into the tank. Measured ethanol content was before the fill up 5% and now 41%. It's good to test different blends before straight E85 ( still winter blend here ~70-75% ).
 
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Last edited by XJR-99; 04-26-2017 at 11:51 PM.
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Old 04-26-2017, 12:43 PM
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what kind of performance gain do you think the E85 give? In the Bugatti Veyron it's 17%!
 
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Old 04-27-2017, 02:03 AM
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Originally Posted by Sean B View Post
what kind of performance gain do you think the E85 give? In the Bugatti Veyron it's 17%!

I would say ~3% without special E85 tune with much more timing. E85 mostly because I want to avoid detonation possibility. My car is flexfuel, so ECU is adjusted to change injector pulses based on ethanol content. Looks like it works well. It's important to use proper oil, Redline alcohol stuff into the tank and E85 graded injectors, fuel lines and rails. Also fuel filter is good to be changed after a couple first tanks.
 
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Old 09-08-2017, 12:37 PM
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The drag race season is over here.....still some complex problems with tuning of the new engine. Most probably needs better ECU to control mixture and timing maps. The power and 10.X are somewhere there....it's sure.
The car below has made some mental problems to focus on XJR tuning issues...
Cheers!
 
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Last edited by XJR-99; 09-08-2017 at 12:42 PM.
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Old 09-08-2017, 05:31 PM
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Do you think a stand alone PCM could be successful in your car? Have you looked into it at all??
 
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Old 09-10-2017, 07:13 AM
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Originally Posted by Addicted2boost View Post
Do you think a stand alone PCM could be successful in your car? Have you looked into it at all??
Exactly what I was thinking
 
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Old 09-10-2017, 09:51 AM
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I had standalone ECU already five years ago, but it was with fixed tune - so not right for the current setup. If you take things seriously, the first thing should be to replace the ECU by much better one. You want to control the engine 100%. These Denso ECUs, specially AJ26S, have some defects to conrrol high boost applications with many modified parts. Too many blown engines because of no active detonation control above 3000rpm.
 
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Old 09-10-2017, 04:47 PM
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A DIY Megasquirt 3 kit sounds right up your alley. Then your controlling your engine 100%
 

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