Aaah... sorry Andre, I confused the numbers in my head between the XKR and STR with the 2.1.

I think I will give fitting the 2.1 a crack sometime next year, I made some initial measurements and it looks good. These twin screws are a hell of a lot of fun, so I can only imagine what the bigger ones are like. Even with the over-spun 1.7, there's so much torque that when I floored it the other night at 50mph the car got sideways

 

What do you guys think about my result with partially opened bypass valve: 291 flywheel HP at 4 psi of boost? Is this result ok or the car should be stronger at 4 psi of boost and twin screw?

 

What was the rwhp and on what type of dyno?

To be honest, it is not a pressure I ever tested, and letting the TS work but not use the power isn't going to give a good picture anyhow. So better get done what needs to be done and do a proper dyno run.

 

I don't know RWHP since there are very few dynos in Poland that measure rwhp. We used to check flywheel hp and loss.

 

I'm back with freshly made measurments.

Vacuum at WOT checked in intake elbow between TB and KB inlet: -2.5 PSI at redline.

Max MAF readings: 260g/s

Max Throttle Position: 75%

Looks like TB needs repair. What do you think?

 

Yes, throttle should be 100% open. 260g/s is roughly 325hp from the crank. I tested my old 80mm BMC CDA and it maxed at 322g/s - back to BMC 85mm cone filter and again easy 400g/s with stock AJ26 MAF.

 

Iirc a stock eaton setup would be around 300-320 gr/sec at wot around 6000 rpm (depends also on environmentals of course), and (according to Count Iblis) the stock intake would have about 140mbar of vacuum (for a 4.2).

2.5 psi would be about 172mbar, so maybe with the 260 gr/sec it could fit. But I have never done these type of measurements (i.e. not fully wot), so can’t say for sure what’s right or not.

Have you checked the throttle opening with the engine not running/ignition on? That will tell in which direction you need to search.

 

Yes, it's max at ignition is 77%. Shouldn't it be 90+%?

 

Also take a look if the butterfly is fully open, which should show as 100%.

Have you checked the throttle basic cable tension? if not that might be your prime issue.

 

Throttle cable was adjusted properly but...

I discovered that accelerator cable cam was blocked by silicone connector of bypass valve. I hope my problem is solved.

 

I agree with Avos and XJR 1999 Finnish bloke about the intake tube- 3 inches isn't much. Oh, and having 3 inches DOESNT improve throttle response- like some companies suggest ;-)


Yes, I know there is a smaller bottle neck- in terms of the MAF sensor- but the retriction is the net sum of all the elements.


Have a look at the post I just did here


https://www.jaguarforums.com/forum/j...6/#post1588418


The 4.2 Jag SC is at around 140 mbars at peak power, the older AJ27 SC is at around 115 mbars.


When you start to try to flow 1700-1900 kg/hr that same intake- even a slightly modified one will quickly get to 220 mbars! 90 mbars should be a better target! But I DO care about refinement and noise both in terms of intake and exhaust