Hi all,
I'd like to see some pics from Xflows with a Simpson exhaust manifold.
I would like to see how they look like on an Xflow and what price you guys paid..
When I want a price I need to bring my car to them, and for me that's a long trip just to see them and know price.
Looked on the facebook page, no photos of an Xflow manifold.
Thanks
Sounds like an expensive trip / exhaust for an Xflow engine. I would order a simple Ashley or equivalent and put the rest of of the saved money elsewhere in the engine where it does make "power for money".Originally Posted by jannes
Ok but I'm thinking of a Tony law or simpson. I now have a ashley similar with primairy 33mm tube sizes. Ashley's tube sizes are 34mm so nearly the same.
Now my Xflow "stops" at 5800rpms, It's like he can't get the gases out fast enough so I was thinking about changing the manifold to one with bigger tube sizes....
what evers causing that it isnt going to be the exhaust manifold!
when you say it stops does it just run out of puff? or does it hit a brick wall and literally wont rev further like its got a rev limiter set too low?
Last edited by Graham; 23-03-2019 at 16:46.
Strange 5800 rpm,
mine with a simple ashley and bcf2 cam, I got easy 6500, and seen on memory tacho 7200 when slide on gravel
maybe you have an issue elsewhere.
For manifold, check martelius website, I used one, it works on LHD car with servo tower !
without having any more info id guess its got a soft or broken valve spring
yep I used to rev 1600 fiesta's with just a bcf2 cam and down draft carb well past that with a cheap Peco full exhaust (remember them) ?
yes i remember them, typically we used to rev them to 7k on a bcf2, well past peak power but they used to go there
34m will start to "choke" power round 160-170 Bhp. Depending the size of engine and RPM. I'm talking about 2 - 3 Bhp. It will not stop round 5800 RPM. It will rev as far as any other exhaust but possible slightly less power.
What's the engines spec??? do you think you are far over 160 Bhp ?
No I don't have 160 Bhp. 140 on the dyno.
When I go to +-6000rpm, it's just like he can't breath enough. He can go further, but very very slowly and not with full enthousiasm....
Specs of the engine: Steel rods & crank, aldon ignitor, Kent cam 244, twin 45s, modified head but I forgot the valve sizes at the moment.
The other issue it can be is, i'm running 34mm choke sizes ?? To small I guess?
id still say theres something wrong else other than the exhaust manifold, maybe you have a silencer collapsed internally, is your rev counter reading correctly? 140bhp @6000rpm sounds like a lot of power for the revs
Can a collapsed silencer cause this problem?? Yes engine power is 136bhp; see dyno test in the link.
https://photobucket.com/gallery/user...NzE2MjI=/?ref=
I thought it can be a combination of the 2; too small chokes and too small exhaust manifold
Last edited by jannes; 25-03-2019 at 12:36.
I don't think at all. 34mm choke will not drop at this kind of RPM, power, same for exhaust. The damper can be a problem but I would always use dampers where I can see from one side to the other so just check.
Re: Xflow Simpson manifold. Pictures?Ok I will check this at the end of the week. I am using a complete Ashley line with 1 damper at the end....
Thanks for the help so far everyone !!
I agree with graham, sounds like valve springs. One of my 1600's had no trouble revving to 8.5k with Kent double valve springs on a DIY ported head with an Ashley 4-1 exhaust using same cam. An head that revved to 9.5k all day suddenly struggled to 7k and traced to springs gone soft. Replaced and back to 9 plus.
My money would be on the ignition (-timing).
Ignition was set on the dyno on lambda 1. If I can remember right, it was set on 6 degrees, less then standard?Then the dynorun was the best
It can be anything, from broken valve up to a simple incorrect tuning. About the ignition setting, please try to find better dyno operator. Did you checked the ignition advance curve of the distributor before setting?Ignition was set on the dyno on lambda 1. If I can remember right, it was set on 6 degrees, less then standard?
Or (very) advanced camtiming.
If I look at you dyno graph, it does not look it "stops" at 5800 RPM. It also not the first one who does setup an engine on a rolling road, mainly in acc. mode and find out in real live the engines stalls in power once driving.
As before, it can be anything but if I look at you graph, there are 2 different worlds talking. It can not be overly complex to find you problem once the engine is on an engine dyno.
I would also assume that either cam timing is out or somethings wrong with the ignition timing.
Do you have an adjustable cam sprocket installed?
On the other hand, I'm not as experienced as the experts above
I was also thinking about camtiming... Because the engine has always ran like it runs now, I never asked myself any question. So I guess the valve springs are not the problem. They were new ordered with the camshaft (double springs). I will check all of this at the end of the week.
Thanks Guys !!
Last edited by jannes; 26-03-2019 at 12:47.
Why was the cam doing fine on the dyno but not on the road? Cam timing does make a big influence on RPM (should have been fitted correct before visiting a dyno). But if you look at the graph, it did what it had to do, it did not stall or dropped at all at the RPM you are talking about.
I think you better give more info about how it stalls at 5800 RPM. Is it like hitting a wall, BANG, 5800 and no step further or more like power fading away? Or more like misfiring once passed 5800 RPM ?
If this engine would have been tuned here and I see a power graph like yours, 5 minutes on the phone and I would be able to tell you what it is by listening to you story about how it stalls. And it is not going to be exhaust, carburetor chokes etc... (that's all waste of time and money)
Currently, none of us is able to make a correct conclusion because nobody knows what you mean with not possible to rev over 5800. The graph you show tell us a different story, that's for sure.
Dirk, you have PB. I'd like your phone nr. I will call you !
Posting Permissions
Reply With Quote
Bookmarks