wedge terminology. .... ..... confused...
Discussion
you'll love it. It's pre hot-wire. Others will tell you the techie stuff.Check this out Mike.............
www.rpiv8.com/carbs-3.htm
''Adjustable (Rising Rate) fuel pressure regulator.'' already fitted on yours.
>> Edited by dickymint on Wednesday 22 February 09:28
www.rpiv8.com/carbs-3.htm
''Adjustable (Rising Rate) fuel pressure regulator.'' already fitted on yours.
>> Edited by dickymint on Wednesday 22 February 09:28
.......................
jon@127 said:
The power boost valve on the RPi Engineering website looks interesting. Does anyone know if this upgrade is applicable to the 2.8 engines?
Jon
No it's not, the fuel pressure is regulated by the fuel distributor on the V8, and the injectors open in response to the fuel pressure. You could wind up (actually shim up) the regulator but you'd cause more problems than you fixed...
Need more go? Sell it and buy a V8...
'Any point'? 
My 390SE had a standard 3.5 AFM on it and as far as I know they all did from the factory. The fact that 'so much more power' was unleashed from the engine would suggest that the standard (ie SD1, Range Rover 3.5) AFM flows enough air to satisfy the demand of a 'tuned' engine (since that's what the NCK motor supposedly is).
However the fact remains that the AFM bore presents the most restrictive part of the intake tract up to the throttle, so fitting the Jag unit must overcome that.
The standard 'corrugated' air hose has 70mm bore each end to fit the AFM and throttle body, so if you fit the Jag unit you either have to fit a larger hose and sleeve it down at the throttle end or fit an adapter to the outlet of the AFM to use the standard hose... which is what I did as a temporary measure (planning a bigger throttle body).
So the Jag AFM is a fairly straightforward fit (well, the air filter won't go straight on, but that's a minor detail)... but it almost certainly won't work on start-up. This is down to the fact that the unit will be calibrated for a Jag ECU and the airflow demand of the Jag engine. You'll need to play with the flap tension spring to get a reasonable idle, and then you take the car out for a drive and (probably) find the throttle response is all over the place! Which is where Mr. Adams comes in... he suggests that merely changing the AFM will cause the car to run lean.
I can't honestly say my car suddenly gained 100 bhp: it DID acquire a different throttle response. However I've changed a lot of things since and only recently found that my ignition pickup was duff and acting as a rev limiter, so I still haven't got the injection set-up anything like spot-on. I did manage to have the car taking off like a jet fighter at certain revs then balking with flat spots 1000 rpm wide at one stage, so there's a lot of adjustments to be made.
I've never had the car on a rolling road, it would have been a good idea to do that at the start so I knew what I was aiming for.
Up to you if you want to try a Jag AFM of course, but be prepared for a lot of twiddling
Sorry if this is a bit disjointed, I'm getting my act together for a trip to Scotland and I keep remembering more things I've forgotten... it's taken me about an hour to type this!
Going back to whether it's worth it: there are plenty of engine tuners who use the larger AFM and also open the throttle body out, so yes, making an easier path for the air MUST be a good idea, but whether any particular engine NEEDS it is another matter...
My 390SE had a standard 3.5 AFM on it and as far as I know they all did from the factory. The fact that 'so much more power' was unleashed from the engine would suggest that the standard (ie SD1, Range Rover 3.5) AFM flows enough air to satisfy the demand of a 'tuned' engine (since that's what the NCK motor supposedly is).
However the fact remains that the AFM bore presents the most restrictive part of the intake tract up to the throttle, so fitting the Jag unit must overcome that.
The standard 'corrugated' air hose has 70mm bore each end to fit the AFM and throttle body, so if you fit the Jag unit you either have to fit a larger hose and sleeve it down at the throttle end or fit an adapter to the outlet of the AFM to use the standard hose... which is what I did as a temporary measure (planning a bigger throttle body).
So the Jag AFM is a fairly straightforward fit (well, the air filter won't go straight on, but that's a minor detail)... but it almost certainly won't work on start-up. This is down to the fact that the unit will be calibrated for a Jag ECU and the airflow demand of the Jag engine. You'll need to play with the flap tension spring to get a reasonable idle, and then you take the car out for a drive and (probably) find the throttle response is all over the place! Which is where Mr. Adams comes in... he suggests that merely changing the AFM will cause the car to run lean.
I can't honestly say my car suddenly gained 100 bhp: it DID acquire a different throttle response. However I've changed a lot of things since and only recently found that my ignition pickup was duff and acting as a rev limiter, so I still haven't got the injection set-up anything like spot-on. I did manage to have the car taking off like a jet fighter at certain revs then balking with flat spots 1000 rpm wide at one stage, so there's a lot of adjustments to be made.
I've never had the car on a rolling road, it would have been a good idea to do that at the start so I knew what I was aiming for.
Up to you if you want to try a Jag AFM of course, but be prepared for a lot of twiddling
Sorry if this is a bit disjointed, I'm getting my act together for a trip to Scotland and I keep remembering more things I've forgotten... it's taken me about an hour to type this!
Going back to whether it's worth it: there are plenty of engine tuners who use the larger AFM and also open the throttle body out, so yes, making an easier path for the air MUST be a good idea, but whether any particular engine NEEDS it is another matter...
Phew, Wedg1e thanks for that very comprehensive reply. I have to say that my twiddling skills are limited, so I can imagine me ending up running very rich or lean or not at all! Maybe a project for the future (if I keep it - keep getting tempted to the dark side of a different TVR until I think sensibly). Maybe cheaper to avoid tuning trickery and just drop a 4.6 short block in - especially as they've started producing RV8s again!!
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