Help 4.2 Inlet Mods

[cruty]

Hi,

I will soon be having my tappets done on my 4.2, so I thought a good time to have a look at improving the flow on the inlet manifolds

The design looks pretty good and all I can see so far (still on the engine) is a small lip in the casting just past the butterflys, which could be taken away and polished.
Reading some of the other threads it seems Joospeed do a mod for the 4.2, but the actual details of what & where the inlets are poted etc are a little scetchy, anybody out there got any clues or tips, plus any idea how much the porting from Joolspeed actually costs?

Thanks very much

[The Phoenix]

Joolspeed? its joospeed

Call him up tomorrow morning - www.joospeed.net

[joospeed]

hi the mods get you at best 12-15bhp. they're by far one of the worst ways to spend your money and I don't recommend you do it unless you're hell bent on geting those 12bhp ! .. making suspension and braking mods and driver trining arer far better ways of spending your money. I do the mods purely because some peole like to talk about hp figures and it's *one* way of getting a bit extra. it's not a good way though...

[cruty]

Thanks for the replies.

I'm not too bothered about the power figures, but was just looking to improve the breathing a little, while the manifolds were off, as I'm looking to do the re-map thing later in the year, so thought the two together would go well, what do you think?

Agree with the suspension mods (I've had nitrons fitted - best mod you can do in my book) and driver training (but only done the instructor thing at track days so far).

Thanks again

[The Phoenix]

cruty said:

Thanks for the replies. I'm not too bothered about the power figures, but was just looking to improve the breathing a little, while the manifolds were off, as I'm looking to do the re-map thing later in the year, so thought the two together would go well, what do you think? Agree with the suspension mods (I've had nitrons fitted - best mod you can do in my book) and driver training (but only done the instructor thing at track days so far). Thanks again

Joo can sort the breathing and get an emerald kit fitted and roller tuned in one go I believe... that would be the next best upgrade after a set of nitrons... also get him to fit the Magnecore kit installed - does make a difference, contrary to what others believe...

[GreenV8S]

I use the Magnecore leads because the last a lot longer than ordinary leads. I would be surprised if there was any performance difference between leads other than durability though, assuming you get the right resistance rating. Can you really tell the difference?

[The Phoenix]

Well, most people say they dont, but I did when I had that change... but it was a combination of better air flow and firing I think... but like anything - we dont bang our cars on the rollers after every little job, but sometimes you do notice an improvement... and with Magnecore, I did... that reminds me - if anyone wants them - let me know, I'm upgrading to Hotwires with 50k coils...

[joospeed]

i think the problem is that the std tvr leads dont last two minutes, well unless you change them every 12k miles or less you soon notice poorer part throttle running and incresed emissions levels.

modern weak mixtures on unleaded fuel are very difficult to ignite, and the V8 cerbie needs all teh ehlp it can get to smooth it's part throttle running out.

fitting the magnecors is a great move

[cruty]

Have got the magnecor leads, which provided a definite improvement in driveability over the original not very good TVR leads (insulation broke down and you could physically see them arcing out on the head of the engine after less than 6k). However I still get a little hesitation/resonance from the engine at both 2k and 4k, especially on light throttle or if in a gear to high, which was one of the reasons behind getting the car re-mapped. Do you know if the inlet ports and exhaust headers match the head casting or is there room for improvement? Plus would there be any benefit from different injectors, which Austec recently introduced. I know the design is different to that of the 4.5 (better I've been told), so would the benefits be greater?

cheers

[Mark Adams]

As usual, Joolz has given you faultless advice (definitely not Mr Hard Sell)!

With regard to the question about injectors, the 4.2 items are from Bosch. They are much better than the later Lucas ones used on the 4.5.

They don't need changing - however they still benefit from ultrasonic cleaning. Most of the sets we have seen are quite manky, but they clean up well! The person who is doing the work should be able to arrange that for you, alternatively send them to Joolz or Austec or Mech repairs!

[joospeed]

lol yeah, I really ought to get a grip on this sales patter malarky