Header dilemma!
Discussion
Evening all,
Again planning for the hopefully not too distant future, what are people using on their higher output SBC setups?
I seem to recall some time ago as a Wannnabe, the factory listed two different exhaust systems which were 'power rated' (and priced accordingly of course).
Now we seem to just have the one on offer, which if I'm not mistaken has 1 3/4" headers?
The problem is, having spent lots of time and money on the engine, in paticular the valve train area I dont want any exhaust restrictions which in turn may cause excess back pressure. Apart from the possible loss of performance I'm most concerned about the extra heat which could induce detonation and/or affect the exhaust valves, oil temps around the head, increase wear, etc,etc,etc!
I have been advised by more than one source that things will be very marginal at 1 3/4" given the likely output/flow/temps of my motors exhaust.
However this engine is considerably smaller in capacity and probably a lot less powerful than many current Ultima Gurus run. So how have you guys tackled the problem, who supplied your sytems?
The heads are standard port AFR 227 elims and I know some will come back and say you cant run larger headers due to stud spacing but there are two seperate ways to resolve this so that is not a big hurdle at the minute.
Cheers for all input.
DW.
Again planning for the hopefully not too distant future, what are people using on their higher output SBC setups?
I seem to recall some time ago as a Wannnabe, the factory listed two different exhaust systems which were 'power rated' (and priced accordingly of course).
Now we seem to just have the one on offer, which if I'm not mistaken has 1 3/4" headers?
The problem is, having spent lots of time and money on the engine, in paticular the valve train area I dont want any exhaust restrictions which in turn may cause excess back pressure. Apart from the possible loss of performance I'm most concerned about the extra heat which could induce detonation and/or affect the exhaust valves, oil temps around the head, increase wear, etc,etc,etc!
I have been advised by more than one source that things will be very marginal at 1 3/4" given the likely output/flow/temps of my motors exhaust.
However this engine is considerably smaller in capacity and probably a lot less powerful than many current Ultima Gurus run. So how have you guys tackled the problem, who supplied your sytems?
The heads are standard port AFR 227 elims and I know some will come back and say you cant run larger headers due to stud spacing but there are two seperate ways to resolve this so that is not a big hurdle at the minute.
Cheers for all input.
DW.
Hi Dave
Difficult one to answer this as every engine is a little different. I'm still running with the original headers which as you say are 1 3/4" OD. I would love to run some bigger headers but I have the power and don't really want to spend any more at the moment. I'm sure with better headers I could free up even more power. I think the ones on Waynes car are 2" OD. After speaking to a few pro chevy engines builders they seem to say that 1 7/8" OD work best.
If you take a look at my car on my mates dyno you can see how hot things get. You can see the silencers glowing red and the headers were also glowing through the ceramic coating. The car was only running 500bhp when the video was taken. I wish I had taken a video when we were trying to hold 600bhp steady state when mapping. The flames were a permanent feature and they were blue(looked like a jet on reheat).
http://www.youtube.com/watch?v=nq5vSgES9Pk
Regards Dave
Difficult one to answer this as every engine is a little different. I'm still running with the original headers which as you say are 1 3/4" OD. I would love to run some bigger headers but I have the power and don't really want to spend any more at the moment. I'm sure with better headers I could free up even more power. I think the ones on Waynes car are 2" OD. After speaking to a few pro chevy engines builders they seem to say that 1 7/8" OD work best.
If you take a look at my car on my mates dyno you can see how hot things get. You can see the silencers glowing red and the headers were also glowing through the ceramic coating. The car was only running 500bhp when the video was taken. I wish I had taken a video when we were trying to hold 600bhp steady state when mapping. The flames were a permanent feature and they were blue(looked like a jet on reheat).
http://www.youtube.com/watch?v=nq5vSgES9Pk
Regards Dave
One answer is to get the stock header altered by a fabricator to fit Stahl header plates. This would open up the area closest to the head but would do nothing for the small primaries. Does Jeff Schwartz make SBC headers for the car? If so you should buy them.
Jeff if you make headers for the SBC let me know.
Ken
Jeff if you make headers for the SBC let me know.
Ken
Edited by k wright on Friday 21st November 00:38
Edited by k wright on Friday 21st November 14:15
Steve cheers, I dont have the luxury of desktop dyno. During the first plan I did mess with Comps' free, on-line simulation but it doesn't calculate my final combo and I'm not using their cam anyway. My cam man did say the bigger the better but did all his calcs (using his own design software)on 1 7/8" so you are correct in that I'm really looking for 2"! (the heads are custom ported to produce good clean flow at the lift I selected, they flow slightly better all round than the comp version)
Dave, thats a great vid but to some degree you may have fewer concerns with your set-up as you are force-fed and turn lower, max RPM. However, do you think it might be worth a look when you fit the new heads etc? Do you run any oil restrictors? Heat to that degree might not enhance your valve-train life in the longer term and after you have set those jesels up properly (not a five minute job!!), you wont want some nasty, worn valve guides allowing the valves to eat into them?? ps, I have an adjustable pushrod if you need to borrow one!
Ken cheers....standing by for Jeff then but I was hoping there might be someone this side of the pond too!
Dave, thats a great vid but to some degree you may have fewer concerns with your set-up as you are force-fed and turn lower, max RPM. However, do you think it might be worth a look when you fit the new heads etc? Do you run any oil restrictors? Heat to that degree might not enhance your valve-train life in the longer term and after you have set those jesels up properly (not a five minute job!!), you wont want some nasty, worn valve guides allowing the valves to eat into them?? ps, I have an adjustable pushrod if you need to borrow one!
Ken cheers....standing by for Jeff then but I was hoping there might be someone this side of the pond too!
738 driver said:
..... a crossover, forget the tuned thoeries or surround sound exhaust systems but might that be a good position for an O2 sensor socket?.........
I would think not. Whilst the cross-over is connecting the systems I doubt there is very much in the way of flow so it would not be my place of choice.Steve
Thanks Steve,
You are probably right!
The only performance-car crossover I remember seeing was a sort of 'X' shape which bridged between two header collectors, hence the suggestion. However, the sort of thing you see on modern bikes, a simple, single bridge pipe would be a waste of time for my thoery.
Rgds Dave.
You are probably right!
The only performance-car crossover I remember seeing was a sort of 'X' shape which bridged between two header collectors, hence the suggestion. However, the sort of thing you see on modern bikes, a simple, single bridge pipe would be a waste of time for my thoery.
Rgds Dave.
JoulesCanAm said:
Contact Craig Bramscher at Brammo Motorsports in Oregon as Spectrum 5 Racing designed and built the set on my car (650HP 427CI Dart small block with AFR heads).
These were a custom software designed set with maximized flow.
Hi JoulesThese were a custom software designed set with maximized flow.
Any chance you could post a pic of your headers? It would be good to see how they look. Especially with you having a Can-Am.
Regards Dave
Would greatly appreciate the photos of Brammo headers.
This is a link to Stahl plates. These allow a large diameter tube not restricted by the distance between the stock exhaust manifold bolts. The plates are machined to match the exhaust port.
http://images.google.com/imgres?imgurl=http://www....
This is a link to Stahl plates. These allow a large diameter tube not restricted by the distance between the stock exhaust manifold bolts. The plates are machined to match the exhaust port.
http://images.google.com/imgres?imgurl=http://www....
Cheers Ken,
Have seen them on E-bay a few times but actually you can fit 2 inch tubes onto a standard exhaust header flange....not as easy to bolt to the head as a stahl pattern though. I would have a go at making them up myself but not done much welding for many years...certainly not stainless!
Any exhaust fabricators in the UK??
Have seen them on E-bay a few times but actually you can fit 2 inch tubes onto a standard exhaust header flange....not as easy to bolt to the head as a stahl pattern though. I would have a go at making them up myself but not done much welding for many years...certainly not stainless!
Any exhaust fabricators in the UK??
738 driver said:
Cheers Ken,
Have seen them on E-bay a few times but actually you can fit 2 inch tubes onto a standard exhaust header flange....not as easy to bolt to the head as a stahl pattern though. I would have a go at making them up myself but not done much welding for many years...certainly not stainless!
Any exhaust fabricators in the UK??
Dave there is a stainless exhaust fabricator in macclesfield who makes cracking exhaust systems... alot of the performance shops get him to make their exhausts... I had a chat last year with him and he knows his stuff... hes made various f3000 race systems so V8 right up his street...Have seen them on E-bay a few times but actually you can fit 2 inch tubes onto a standard exhaust header flange....not as easy to bolt to the head as a stahl pattern though. I would have a go at making them up myself but not done much welding for many years...certainly not stainless!
Any exhaust fabricators in the UK??
website http://www.jpexhausts.co.uk/
dom
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