My last 4 cars all ended up with modified manifolds due to the fact that the standard ones where restrictive - why do Bmw/Ford etc not make some unrestrictive manifolds and then we could all enjoy 10% more power and additional noise ? 10% of 367bhp is quite a lot more power !!
Last edited by madmax; 23/10/1612:12 PM.
Geneva 2016 plus 8' The Green Godess' 4 side exits .
My last 4 cars all ended up with modified manifolds due to the fact that the standard ones where restrictive - why do Bmw/Ford etc not make some unrestrictive manifolds and then we could all enjoy 10% more power and additional noise ? 10% of 367bhp is quite a lot more power !!
Because the bean counters always win. The cost/benefit ratio just isn't justified in mass production. This might change in the future as fuel efficiency becomes the driving goal.
The biggest single gain I've seen from one of my manifolds was on my HSCC Fiat X19 When I bought the car it was fitted with an Ansa aftermarket manifold and had been dynamometer tested with 96 BHP (ok for a non cross flow 1300cc engine on a single carburettor) I ran some engine simulations and redesigned and fabricated a new exhaust manifold and system, tweaked the carburation and cam timing to suit, and was rewarded with 128 BHP (and an engine that would rev out to over 10,000 rpm) That's a 33% gain and damn near a 100 BHP/ltr The next iteration of engine I was in the process of building would have pushed about 150BHP out, sadly we decided to go 24hr racing with the Aero and that pretty much curtailed my racing exploits. I sold the X19 in 2009 and it's now very successfully used for FIA historic rallying
I understand Simon will make a side and mount it on an Ash plinth, pipes plated, so you can fit it under a glass topped table in the living room, or man cave!
A lot cheaper than buying an Aero.
stop it Peter;I was just about to put this on my Christmas list.......
James
Aero8 , Series 1 - Boston Green RR Evoque P300E Autobiography Smart Brabus Convertible Monkey Z125
This is the second pair/set of two prototype manifolds I've made.
They will be going away for ceramic coating next week, and should be fitted on cars soon for testing. We're hoping for some substantial gains in engine response, along with useful gains in power and torque.
Simon @ SiFab.co.uk
I saw this header on RPI (Chris Crane) website and decided to build it myself. Compared to Simon's header the one I made is simple. It is made of mild steel. I am not a welder. By the time I got a proper welder to finish this $$$$$$$$$$. I should have purchased Chris's offering in stainless.
Unfortunately about the only thing I can say about the RPI headers is that they fit....
I know the chap that originally commissioned them...
I've fitted a set, tested them, and then removed them, threw them away and fitted a Librands manifold.... Instant and measurable performance increase...
Unfortunately about the only thing I can say about the RPI headers is that they fit....
I know the chap that originally commissioned them...
I've fitted a set, tested them, and then removed them, threw them away and fitted a Librands manifold.... Instant and measurable performance increase...
Simon @ SiFab.co.uk
Interesting. Did You test them by the seat of your pants, or a rolling road? I used a rolling road to test the complete engine but did not have comparative information on other headers. The results were not spectacular. I have since replaced My 3.5 engine with Buick 215 heads with a Morgan 3.9. (sourced from Bill Fink) Very much improved.
Unfortunately about the only thing I can say about the RPI headers is that they fit....
I know the chap that originally commissioned them...
I've fitted a set, tested them, and then removed them, threw them away and fitted a Librands manifold.... Instant and measurable performance increase...
Simon @ SiFab.co.uk
Interesting. Did You test them by the seat of your pants, or a rolling road? I used a rolling road to test the complete engine but did not have comparative information on other headers. The results were not spectacular. I have since replaced My 3.5 engine with Buick 215 heads with a Morgan 3.9. (sourced from Bill Fink) Very much improved.
I'm afraid my pants are nowhere near accurate enough....
Everything I make gets thoroughly tested, before it gets released to the public. In the case of engine performance modifications , that means either on an engine or rolling road dynamometer, with back to back testing and any tuning necessary to gain maximum benefit.
I wouldn't want cars failing any emissions tests if fitted with my upgraded parts for example.
A lot of the time I'll carry out a lot of hand calculations and virtual load testing on components in the design process.
The rear axle/driveshaft/wheel bearing conversion I designed for the Peking-Paris +4 would be a good example of this.
