Chimaera 450 SC Problem

[BoostedChim]

Richard 858 said:

+1 on interest in an update, especially as I've now had mine tested. With the same charger & engine set up, but still on the 14CUX, Bosch injectors, standard fuel pump but switched back to stock B7 plugs I am running 6 psi of boost, however I was & still am experiencing some belt slip at 5,000 (ish) engine rpm. My numpty comment earlier in the thread about dump valve spring should be ignored

Have you tried swapping to a smaller belt? As the tensioner is a clock spring the smaller the belt the more tension it puts on the system. We found with an 85mm pulley and the supplied belt it was not putting enough tension on the supercharger. I tried fitting a couple of smaller belts until they only just went on with the tensioner on its stop. It hasn't squealed since.

[Richard 858]

Yes I did fit a 30mm shorter belt & no more squeal or slippage. However since then I have a slight tapping noise which I'm unsure about. I've run the engine briefly without a belt on at all but the noise is still there but quieter Also the boost now experienced over 5,000 rpm has shown up a misfire so just changing a few components to iron it out, then we'll see the full result, hopefully.

[Stevie Mojo]

chris watton said:

I cannot help or give advice - but just wanted to add that those pictures are pure TVR porn! Astounding work and attention to detail!

Hope it gets sorted PDQ!

Agreed.

[AceOfHearts]

Any updates?

[Richard 858]

Update from me - Tapping noise was slightly loose exhaust manifold / slightly blowing manifold gasket. Misfire cured by fitting new distributor cap & rotor arm.
Recent RR dyno run gave 430 hp & 425 ft.lbs. at flywheel (curves posted on "post your dyno curves here" thread) and I'm happy with that, particularly given I'm still on 14cux, single coil and distributor.

Edited by Richard 858 on Sunday 30th November 17:37

[AceOfHearts]

Wow impressive numbers! I'm planning on getting a V8D 4.6 and going forced induction next year so I am fitting megasquirt at the moment in preparation. Exciting stuff!

[Richard 858]

Thanks Lewis, I'd be careful about the compression ratio and cam choice and make sure Rob knows your F.I. plan, it'll help enormously later on.

[Mr Supercharged]

You may want to consider a cam ground specifically for FI, Reel Steel make one, I think V8 Tuner does too. You are looking for a cam with little overlap to avoid pumping your compressed air out of the exhaust. I don't believe V8D make a cam like this, perhaps they can or perhaps you can free issue one from another supplier?

[Hoofa]

Rob will do a special of you ask him, that's what's in mine

[cinquecento]

Stumbled across this. Doing a S/C install on my Griff so I am curious... any update?

[Richard 858]

Blimey, not another Griffer straying onto this forum! must be a reason Mine is still running fine, soon to fit new stainless exhaust manifolds as found a small hole in the old ones and fancied a smarten up. are you fitting the Rotrex / SC Power kit ? I'm not sure of the differences in a Griff installation but I would have thought they are fairly minor. I'm glad to be of any help that I can be if you have any questions please pm me.

[450Nick]

The only issue I've had of late has been the recirc valve seems to be opening a bit early... Maybe the spring is weakening when the body gets heated up by the exhaust - anyone had this problem, and if so has anyone looked into a fix?

[Richard 858]

hi Nick, I don't appear to have suffered this problem (yet ?) but my dump valve (as part os Sc Powers kit) came with a spare spring (red) which I believe is stronger. I'm sure you'll be able to get stronger / spare springs direct from Forge.

[Mr Supercharged]

If you over speed the supercharger by much the boost level reduces significantly. This can give the impression that you are losing boost through the valve when in fact all you are doing is operating the charger too fast. If your valve is genuinely opening you can get stronger springs from Forge, you can also use shims too.

[Hoofa]

I went away from the supplied valve as I was losing boost, one problem is the valve doesn't always close correctly as it is possible the piston doesn't always close centrally, it then catches on the side .the new valve has a guide to prevent the piston closing on the piss.

[cinquecento]

Long time lurker on the Chimaera forums..don't get that many TVRs here so we are one big happy family.
Thanks for all the tips and input. I am installing the S/C over the next week so while I am looking forward to driving the car, I'm appreciative of any support should there be teething problems.

My last update on the Griff forms is here

[carsy]

Bit of a thread revival, but did this problem ever get sorted.

[Bluebottle]

I've had this situation, and SC Power can supply a stronger spring...not had the issue since (also check the recirc valve is actually working properly and isn't sticking in operations..I've had to replace one because of this)