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No point on the forced induction they run out of steam at 6500rpm different with the n/a - more rpm = more bhp .
These engines share the same valve springs , valves as the AM 4.3 vantage (4.7 larger valves) and have also been tested up to 7500.
If the blower engine's power band is huge but drop off at 6500 rpm, that means its time to SHIFT, get back INTO that huge power band. RPM does not equal power or speed. Usage OF the power band is what allows power to be used.
The BHP you tout at 7500 rpm is still much lower than the supercharged power at 5500 rpm.
Therefore, blower at 5500 beats the snot out of over-revving the n/a engine.
If the blower engine's power band is huge but drop off at 6500 rpm, that means its time to SHIFT, get back INTO that huge power band. RPM does not equal power or speed. Usage OF the power band is what allows power to be used.
The BHP you tout at 7500 rpm is still much lower than the supercharged power at 5500 rpm.
Therefore, blower at 5500 beats the snot out of over-revving the n/a engine.
No question about that at all and plus the torque out of the forced induction unit .
For me Cee Jay the goal is to get my n/a just as quick or as close to a stock xkr 4.2 once that is achieved I'll either jump ship into a 5.0 xkr or 5.0 ftype where there's no need to play around with diff ratios or up the rpm limiter
From my Drag Race Engine and Racing days.......
"Max Torque Curve at the Shift Recovery Point".
Horsepower isn't the magical wizard, it's how you use it.
Took the XKR on a the 63rd annual NY Metro PCA Snowflake rally this past Sunday. Finish 4th overall out of about 30 cars and 1st Jaguar out of the 3 entered.
From my Drag Race Engine and Racing days.......
"Max Torque Curve at the Shift Recovery Point".
Horsepower isn't the magical wizard, it's how you use it.
Cee Jay I really don't get what your trying to say ?
The n/a went 13.6 @6250rpm then 13.4 @7400rpm with increased limiter
Last edited by steve_k_xk; Feb 9, 2023 at 10:10 PM.
On hard acceleration, the other day, my check engine light came on. The car was running fine, so I cleared the code -p0171- but it quickly returned. Took it in to my Indy shop, they did a smoke test and found some old, brittle vacuum lines were cracked and leaking. He also found that the air intake wasn’t properly installed and also showed some smoke. Happy to report that it’s running great!
1. Battery age: this car needs >12.5 v consistently, more like 12.8. Use an AGM, quality unit, and try to keep it to 12.8 or above. Use a battery maintainer every night.
2. Don't leave your key near the car. Car detects it and may not shut down properly.
3. Car shuts down to about 50 milliamps in 3 minutes if you double lock it. Double lock it every time you shut it off, and it will shut down quicker.
On hard acceleration, the other day, my check engine light came on. The car was running fine, so I cleared the code -p0171- but it quickly returned. Took it in to my Indy shop, they did a smoke test and found some old, brittle vacuum lines were cracked and leaking. He also found that the air intake wasn’t properly installed and also showed some smoke. Happy to report that it’s running great!
New owners:
Said this a few times: the seals harden and shrink on these over the years. This p0171 code indicates that the Long term Fuel Trim (LTFT) mixture has leaned out beyond 20%, when it should be zero. The only practical way to find all the leaks is a smoke test. The brittle lines mentioned above were likely the thin grey ones going to the AIR unit from the back of the throttle body. Incredibly fragile, they break easily. A poorly fitted intake to the throttle body is really easy to do, as the part on the underside of the TB gets missed. In addition, o-rings shrink, on various lines, as well as the 4.2 model injectors. The oil cap and the dipstick seal also dry and leak. Lots of small leaks add up.
If you want to know if you have vacuum leaks, check your LTFT on each bank. If either varies more than 5% or so, you likely have a leak somewhere. Leaks can affect an individual bank, but usually affect both. The only practical way to find the problem is a higher pressure smoke test -- meaning use something stiffer than a rubber glove over the throttle body.
Good luck.
Last edited by panthera999; Feb 13, 2023 at 10:22 AM.
Got mine back from polishing and ceramic coating today, very happy with how it turned out. Sadly the sun wasn't out for the after photos but you can see how the Botanical Green pops under the lights in my detailer's garage:
Those look great in black!👍 But, kinda trying to convince myself into a Mina back box!😂🤣
By the way, do you still have your original back box in place? Also, did you notice much difference (in anything) after installing your X-pipe?
Cheers
