Matt Sullivan Posted November 13, 2002 Share Posted November 13, 2002 Looking to change my 5" competition exhaust to a repackable one, not sure what to do about the inlet. The collector is 4-1 with the inlet to the silencer 2". Talking to Ammo at Raceco, he advised the possible way to go would be to increase the inlet size on the collector (requires cutting, replacing and welding). I don't want to faff about too much and wondered whether I'd notice much gain considering its 2.0 Swindon 235 (yeah right) on 48's anyway. Getting a bespoke full system at the moment is a bit prohibitive cash-wise, but at 109db a new repackable silencer is a must. I've heard some iffy reports about Techcraft, so I'm looking at raceco or H&S. cheers, Matt. Link to comment Share on other sites More sharing options...
I reply to every thread Posted November 13, 2002 Share Posted November 13, 2002 H&S in my opinion (For what it's worth) Link to comment Share on other sites More sharing options...
Matt Sullivan Posted November 13, 2002 Author Share Posted November 13, 2002 Matthew, I remember the seeing the pictures of your H&S exhaust, and it looks pretty neat. Mine's an early HPC with a 2" diameter pipe - just wondering what the benfits are, if any, of increasing this if I'm going to have a bespoke pipe built. Link to comment Share on other sites More sharing options...
Foxy Smith Posted November 13, 2002 Share Posted November 13, 2002 Matt, Like yourself I have a Swindon Vx. I happened to be visiting Ammo to collect some books I'd bought from him and in the couse of one of those tyre kicking conversations Seveners have he sold me a new silencer and also convinced me that a 2" silencer header was too small for this engine spec. The upshot was I bought one of Raceco's first Titanium silencers and when it arrived it was accompanied by a short length of 2.5" S/S tube. This tube was used with the exhaust system partially assembled to determine where to cut the 4-1 collector. Very easy, I did all the marking and cutting myself but had a local shop do the welding as I wanted it TIG welded as its a visible item. The bottom line. Absolutely the best thing I've done to the car. Bags more torque, revs more freely. The car is much faster but much easier to drive, don't need to change gear just leave it in fourth (not quite!) Sounds good too, deeper note but much quieter with the new silencer (don't tend to wear ear plugs) I would strongley recommend increasing the outlet size to 2.5" and think Ammo's silencers are a good product, hand made to a very high standard by Mick Riley (also a seven owner) Alan Link to comment Share on other sites More sharing options...
I reply to every thread Posted November 13, 2002 Share Posted November 13, 2002 From what I know (& FA will correct me if need be) you will get real benefit if in addition you chage the headers to equal lengths. H&S have a jig for the whole system inc headers & it's a lot cheaper than FA paid for his now he's underwritten the development costs! Link to comment Share on other sites More sharing options...
Paul McKenzie Posted November 13, 2002 Share Posted November 13, 2002 I thought you also had to increase the diameter of the primaries a la JPE, or is this not necessary if you just increase diameter after the collector? Where's FA? Paul Link to comment Share on other sites More sharing options...
Julian Thompson Posted November 13, 2002 Share Posted November 13, 2002 FWIW, my VHPD K series made 209bhp with the 2.25" raceco Ti exhaust and an Emerald ECU. That's 19bhp over standard! My collector was taken from 2" to 2.25" by Mike Riley, who makes the Raceco exhaust for AMMO. In addition, my car was measured at Oulton Park at 96db!!!! Fantastic!!!! Link to comment Share on other sites More sharing options...
Paul McKenzie Posted November 13, 2002 Share Posted November 13, 2002 two-thirds max. revs = 3000rpm.......the noise tester thinks we all drive diesels Paul Link to comment Share on other sites More sharing options...
EFA Posted November 13, 2002 Share Posted November 13, 2002 Oi Aves, theres a £50 royalty charge for using my jig......... Fat Arn Visit the K2 RUM website See the Lotus Seven Club 4 Counties Area Website here Link to comment Share on other sites More sharing options...
Matt Sullivan Posted November 14, 2002 Author Share Posted November 14, 2002 I was reading an old post by AVES re: fitting his new H&S silencer. A straightforward swap with very little faffing about. This is exactly what I'm looking for, but if increasing the collector to 2.5" will give me noticeable improvements, then its probably worth it. cheers. Link to comment Share on other sites More sharing options...
StewartG Posted November 14, 2002 Share Posted November 14, 2002 Julian, how much does Mike Riley charge to increase the collector outlet and how long did he take to do the work? Link to comment Share on other sites More sharing options...
Julian Thompson Posted November 15, 2002 Share Posted November 15, 2002 It took Mike about 2 hours work to increase the size and he charges a reasonable rate per hour. I can't remember the exact amount but it was not an issue. He actually fashioned a new piece of pipe to smooth into the 2 outlet of the collector; it was not just a bodge job. The result is so good that nobody ever even notices it ❗ Top man. Link to comment Share on other sites More sharing options...
EFA Posted November 15, 2002 Share Posted November 15, 2002 "A straightforward swap with very little faffing about!" Thats what using my jig provides. The 2.5" is also built on the same jig, so I'm on to £50 both ways! The joys of IP...... Being serious, the 235 will breath much better with a 2.5" collector. Do it. Hayward and Scott will charge around £50 to modify the collector and will also make a #4 primary so all 4 are very close to equal length for a similar amount. They are on 01268 727256 Fat Arn Visit the K2 RUM website See the Lotus Seven Club 4 Counties Area Website here Edited by - fat arnie on 15 Nov 2002 22:46:13 Link to comment Share on other sites More sharing options...
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