Exhausting questions

[caterhamnut]

I have just fitted an uprated starter motor (Caterham race one - 1.4kWetc) to our car - needs it to crank the 'new' engine faster and start on the Emerald, which it now does

However I really need to also upgrade the exhaust system, as it all hits - manifold nearest the back of the engine just misses the corner of the solenoid. Caterham 4-2-1 manifold misses this with much more of a gap, but of course costs.

Does anyone know how much the manifolds from Caterham are (I know I can ring, but just too late!) - alternatives/options.

 

In the mean time, I have gentle peened (bashed!) the manifold a little so there is now a 5-10mm gap between solenoid and exhaust, and have also wrapped the solenoid in heat shield matting (foil on one side of glass mat) Now of course, this closes the gap again, so the 2 are just about touching. Accepting that this is not ideal, what else can I do. Would some exhaust wrap help, and is it ok to just use this locally, or will this cause uneven 'hot-spots' etc.

 

Which is better:

5-10mm air gap between hot thing and expensive thing

2mm air gap and heat shield matt between hot.......

?

 

 

Big update!

here

80,000miles in 3 years plus

 

Edited by - angus&tessa on 15 Aug 2005 17:24:08

 

Edited by - angus&tessa on 15 Aug 2005 17:24:55

[Sheds Moderator]

Hi Angus,

Since nobody else is giving you any opinions I will. I'd go 2mm airgap and shield. Why? Because without doing any maths at all I think that a lot of exhaust heat will be radiant. The difference between 2mm air and 10mm air will not really affect radiant heat. After all a few miles of atmosphere doesn't take too much sting out of the heat of the sun. A reflective blanket however will help a good deal. I'd also say that anything that can keep the starter nice and snug against the bellhousing can be regarded as A Good Thing since the castings never significantly exceed 100C (if they do a K series will be long dead 😬).

 

Offset against this is that 2mm air will allow heat to convect more easily across the gap, but I think the balance is in favour, especially since the starter is bolted up to the best heat sink in the world, 100kg of metal.

[Grubbster]

I don't have the prices for just the manifolds, but a while ago I enquired aboout complete system prices if this helps:

Roadsport Race 4-1 system. System £495+VAT, fitting about 3 hours at

£52/hr+VAT (includes cutting the new hole etc). Not suitable for use with a catalytic convertor.

 

SLR 4-2-1 system. Has improved flow over above. Non-cat system £595+VAT, similar

fitting.

 

R500 4-1 system. Has improved flow over both of the above. Non-cat system

£810+VAT. Silencer repackable. There is also a version of

this exhaust with a larger, quieter silencer (£895+VAT). Fitting as above.

---

Alternatively see if Dave at Powerspeed can help? I got my 4-2-1 from him earlier and there is plenty of space between the primary and the starter.

 

Roadsport build photo's here

Le Mans 2004 photo's here

 

 

Edited by - Grubbster on 16 Aug 2005 13:57:35

[Tony C]

Try Graham at Exhausts By Design here

 

Excellent quality and he'll make it to measure - not expensive either 😬

 

BRG Brooklands SV 😬 It seems that perfection is achieved not when there is nothing more to add, but when there is nothing more to take away. (Antoine de Saint-Exupery)

[caterhamnut]

cheers guys - I was beginning to wonder if anyone had any opinion at all!

I've bashed a little more and got the gap to about 10mm, reckon I might put one thin layer of heat refelctive stuff on the solenoid, as long as the air gap stays. Yesterdya, before further bashing, the blanket was touching the manifold - not ideal!

 

Big update!

here

80,000miles in 3 years plus

[I.Mupferit]

Would it be a reasonably cheap mod to simply get the offending pipe modified/rerouted a tad with a bit of judicious bending & welding by one of the exhaust manufacturers?

 

Just a thought.

 

Brent

 

2.3 DURATEC SV Reassuringly Expensive

R 417.39 😬

[caterhamnut]

Probably Brent - but not by this weekend

Certainly fettling existing pipe is probably the best option, but would need to arrange trip to said bender 😳 with car etc for measuring, and hope to get it done 'on the spot' otherwise it is a bit of a b*gger with no car....reckon we are ok for now

 

Big update!

here

80,000miles in 3 years plus

[J A T Richardson]

I'd have to take issue with the statement "After all a few miles of atmosphere doesn't take too much sting out of the heat of the sun. " Those few miles of atmosphere (approximately 1 10,000th of 1% of the distance sun-earth) mean that we get surface temperatures of between 60 degrees and minus 60 degrees, from something that starts at 20 million degrees and even in space near the earth is plus/minus LOTS more than 60...

 

Why DID I feel the need to write this??

 

 

 

Stinky toy driver - and proud of it!

[caterhamnut]

😬

 

Big update!

here

80,000miles in 3 years plus

[Sheds Moderator]

😬 I knew someone from pedants anon would be along soon. 😬

[SimonRHC]

Hi Angus & Tessa,

I'd say try a decent heat shield (maybe fiberglass lagging) before forking out for special exhaust pipes.

i haven't read all the threads on k-series hot start problems because i've got a vx.

I'd get as much lagging around all the exhaust pipes to lower the underbonnet temp.

i think that you'd be better off with a small air gap and thick lagging.

you may get to the point where the outside of the lagging is not too hot to touch.

the general underbonnet temperature is a problem and the other pipes will add to this. the underbonnet temperature goes through the roof when you stop moving and the air flow stops.

as the solenoid coils heat up their resistance drops.

the magnetic "pull-in / hold-in" force is directly related to the coil's "amphere turns" which has been reduced to the point where it's insufficient to function normally.

I hope this helps / works.

Simon