Stainless Manifolds

[SI 4.3]

I have finished fitting a pair of stainless manifolds 8 bolt including the y section from J P Exhausts and I must say Trik at JP they are a work of art. Had the usual problem with the originals cracking,welded righthand one up but only lasted a couple of months but must have also had a slight blow on the left hand side.Anyway the Griff has never sounded better and the quality from JP outstanding.

[bugsy]

SI 4.3 said:

I have finished fitting a pair of stainless manifolds 8 bolt including the y section from J P Exhausts and I must say Trik at JP they are a work of art. Had the usual problem with the originals cracking,welded righthand one up but only lasted a couple of months but must have also had a slight blow on the left hand side.Anyway the Griff has never sounded better and the quality from JP outstanding.

I agree absolutely, well impressed with the product.

[JonRB]

How much did they cost, if you don't mind me asking? It would be good to know how much to budget for as one of my manifolds has already had a weld repair.

[andy43]

Precat manifolds and y-piece, fitted at JP, I paid close to a grand from memory, but you're right, they are an absolute work of art
If you need 'em fitted, I'd go to JP, if not, ACT or Steve Reid may do them slightly cheaper.

[SI 4.3]

The cost of the stainless manifolds from JP including the Y piece and 16 stainless blots for the flanges was £857 inc VAT and postage.A gasket set from peninsula was 40.00 all in,also if you have them fitted you looking at about £180 well worth it IMHO.
Regards
Simon

[Boosted LS1]

They sound really good but stainless expands more then mild steel so won't they be more prone to cracking later on? Are the bolt holes larger then stock so as to allow room for expoansion? I'm not knocking the product but just curious that's all.

Boosted.

[SI 4.3]

Noted however JP have been making manifolds for a hell of a long time and must of improved their porducts over the years.
The problem with the pre cat manifolds as I understand it is the 4 pipes had a weld run into the gap in a number of places to brace the pipes.This would and indeed has been the cause of 90% of cracking problems.
JP now do not run weld into the gap,they put a high quality stainless steel brace around the pipes to stop the above problem.
Perhaps the man himself (Trik at JP)could pass comment after all he is the expert.

[David H]

Boosted LS1 said:

They sound really good but stainless expands more then mild steel so won't they be more prone to cracking later on? Are the bolt holes larger then stock so as to allow room for expoansion? I'm not knocking the product but just curious that's all. Boosted.

Standard manifolds are stainless.

[Boosted LS1]

Ah, I was probably thinking along the lines of heat being produced with turbo's in which case stainless is pretty much a no no

Boosted.

[virgil]

Boosted LS1 said:

Ah, I was probably thinking along the lines of heat being produced with turbo's in which case stainless is pretty much a no no Boosted.

Are you sure it's not more of a case of stainless is 'less flexible' than mild steel and therefore may be more prone to crack? Also the difference in behavour between stainless and mild in relation to heat treating/annealing in air could be another reason to aviod SS in high heat areas like turbo manifolds.

Just a thought...back to work now

[Boosted LS1]

virgil said:

Boosted LS1 said: Ah, I was probably thinking along the lines of heat being produced with turbo's in which case stainless is pretty much a no no Boosted. Are you sure it's not more of a case of stainless is 'less flexible' than mild steel and therefore may be more prone to crack? Also the difference in behavour between stainless and mild in relation to heat treating/annealing in air could be another reason to aviod SS in high heat areas like turbo manifolds. Just a thought...back to work now

I think stainless will expand more, especially with boosted temps so you should enlarge bolt holes and have expansion joints where appropriate. This isn't needed for an atmo engine. Turbo's keep a lot of heat in the manifolds.

Boosted.

[andy43]

I think I remember Trick saying to me the original manifolds were all slightly on the p!ss, as the TVR jigs were off a bit, causing tension and then cracking around the initial 90 deg bends from the cylinder heads. Or something.