DEVEK Header Sale
10-02-2005, 11:18 PM
#61
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10-08-2005, 01:05 PM
#63
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price is $600 in mild steel.
Are there any other options for a 3" X pipe except for the plain jane ones like magnaflow makes?
Might just have to get an Ott one fabricated locally in 3" pipe to hook up to the headers that I hope to get soon......
10-08-2005, 01:26 PM
#64
Drifting
I can get Dr. Gas's 3" X-overs to be used in custom 3" exhausts, I will check with them on the price. It will be a weld in "off the shelf" X but they do work considerably better than the Magnaflow X which is created out of convenience, not power production.
10-08-2005, 03:05 PM
#67
Wouldn't the equal length headers kind of do what the x is doing with the stock manifolds?...I always thought that is what header did...equal length and scavanging effect on neighboring exhaust ports?. I don't think that the X at the end of the the headers would have much left to scavange. A local PACNW 928 owner had the Devek Level II headers and fab'd up an x based on Louie's design. Don't remember exactly, but didn't think he gained much over the merge collector he had on there before?..
Later,
Tom
89GT
Later,
Tom
89GT
10-09-2005, 01:25 AM
#68
Three Wheelin'
Originally Posted by John Veninger
Dave,
I thought the Dr. Gas X was "to short" compared to the Ott X that is a "longer" X and better for the 928.
I thought the Dr. Gas X was "to short" compared to the Ott X that is a "longer" X and better for the 928.
I'd steer clear of their "Tandem custom crossover junction". The angles are too abrupt, and besides it's for Corvettes and trucks.
The reducer cones can be found here. http://www.drgas.com/item.asp?id=512I may use that configuration or else go with two of these 2 into 1 merge collectors with the ends cut off and welded together. http://www.drgas.com/item.asp?id=49 Possibly one half of the XScreamer on the front and one of these merge collectors on the rear. Still a ways off for me to think about right now.
10-09-2005, 01:52 AM
#69
Originally Posted by Tom. M
Wouldn't the equal length headers kind of do what the x is doing with the stock manifolds?...I always thought that is what header did...equal length and scavanging effect on neighboring exhaust ports?. I don't think that the X at the end of the the headers would have much left to scavange. A local PACNW 928 owner had the Devek Level II headers and fab'd up an x based on Louie's design. Don't remember exactly, but didn't think he gained much over the merge collector he had on there before?..
Later,
Tom
89GT
Later,
Tom
89GT
Dude, Louie is like one of the masters... you must respect...
Hehe
I think that the idea is that with the firing order of a V8 you get two from the same bank firing consequtively....
what you say would be true if the banks always alternated... but that ain't the way it works...
Here is the Zundefolge.... I think that is the way Gerry spells it....
1-3-7-2-6-5-4-8
Louie is this the right logic?
Some have said that the later style welded stainless steel manifolds are not too bad because they increase in diameter as they go back. Also are the devek headers actually equal length. Some have said they are as close as you can get given the small space. I kind of figure that the X would be good money spent and I will put headers in when I yank the engine out.
I should have put in headers when I have the crossmember out this summer... I didn't want to wait for the new batch... but as is turn out the many of my other issues with the car have made it so i have driven the car very little...
hindsight...
LO
10-09-2005, 02:02 AM
#70
Drifting
Hey John!
Louie is right on the money describing our X. It's a very close copy of his but with some subtle changes. Ours is considerably longer than the generic Dr. Gas X's and is custom designed for 928's, not just an X thrown in to fit.
The difference between the inlet angles, the outlet angles, the size of the opening between the chambers and the distance of the X from the exhaust ports are all critical as well as the dimension of the bends.
A normal X will provide horsepower gains over a factory H junction but is not optimized at all. You can expect almost double the gain of a generic X with a proper design.
Louie is right on the money describing our X. It's a very close copy of his but with some subtle changes. Ours is considerably longer than the generic Dr. Gas X's and is custom designed for 928's, not just an X thrown in to fit.
The difference between the inlet angles, the outlet angles, the size of the opening between the chambers and the distance of the X from the exhaust ports are all critical as well as the dimension of the bends.
A normal X will provide horsepower gains over a factory H junction but is not optimized at all. You can expect almost double the gain of a generic X with a proper design.
10-09-2005, 03:42 AM
#71
Three Wheelin'
Originally Posted by lorenolson888
Hi Tom,
Dude, Louie is like one of the masters... you must respect...
Hehe
I think that the idea is that with the firing order of a V8 you get two from the same bank firing consequtively....
what you say would be true if the banks always alternated... but that ain't the way it works...
Here is the Zundefolge.... I think that is the way Gerry spells it....
1-3-7-2-6-5-4-8
Louie is this the right logic?
Some have said that the later style welded stainless steel manifolds are not too bad because they increase in diameter as they go back. Also are the devek headers actually equal length. Some have said they are as close as you can get given the small space. I kind of figure that the X would be good money spent and I will put headers in when I yank the engine out.
I should have put in headers when I have the crossmember out this summer... I didn't want to wait for the new batch... but as is turn out the many of my other issues with the car have made it so i have driven the car very little...
hindsight...
LO
Dude, Louie is like one of the masters... you must respect...
Hehe
I think that the idea is that with the firing order of a V8 you get two from the same bank firing consequtively....
what you say would be true if the banks always alternated... but that ain't the way it works...
Here is the Zundefolge.... I think that is the way Gerry spells it....
1-3-7-2-6-5-4-8
Louie is this the right logic?
Some have said that the later style welded stainless steel manifolds are not too bad because they increase in diameter as they go back. Also are the devek headers actually equal length. Some have said they are as close as you can get given the small space. I kind of figure that the X would be good money spent and I will put headers in when I yank the engine out.
I should have put in headers when I have the crossmember out this summer... I didn't want to wait for the new batch... but as is turn out the many of my other issues with the car have made it so i have driven the car very little...
hindsight...
LO
Yup, you are right. I should have explained further. The uneven firing order still needs some sort of way to help the overlapping exhaust pulses escape. The large diameter header collector helps and I suppose if we were running open collectors it wouldn't matter if we had a crossover or not. The primary tube lengths help scavenge other cylinders on the same side of the engine at certain rpms and even that is messed up with the uneven firing order. An X should help with headers and a full exhaust.
10-09-2005, 02:27 PM
#72
Hey Loren,,
Yes...we in the PacNW...realize that....but every once in a while we need to coax the Prof. out of his compound so others can benefit from his knowledge
Only reason I posted was to be devils advocate..in the sense that we've had GT's with stock manifolds and Louie's X....put down the same numbers as a devek level II header and modfied Ott X...
Now to pose another question..we've worked on a 83 with a 84 euro motor in it....equipped with msds headers....but the two sides never mated up...as in two pipes cats etc..back...its dyno numbers were not what was expected...so.....would a crossover after the MSDS headers help.?..or put it after the cats?...or a simple connection tube (ala H pipe)...and how much would he concievably gain by addding the above?..
thanks
Tom
89GT
Yes...we in the PacNW...realize that....but every once in a while we need to coax the Prof. out of his compound so others can benefit from his knowledge
Only reason I posted was to be devils advocate..in the sense that we've had GT's with stock manifolds and Louie's X....put down the same numbers as a devek level II header and modfied Ott X...
Now to pose another question..we've worked on a 83 with a 84 euro motor in it....equipped with msds headers....but the two sides never mated up...as in two pipes cats etc..back...its dyno numbers were not what was expected...so.....would a crossover after the MSDS headers help.?..or put it after the cats?...or a simple connection tube (ala H pipe)...and how much would he concievably gain by addding the above?..
thanks
Tom
89GT
10-09-2005, 03:25 PM
#73
Hi Tom, Good Job...
That is interesting. Sounded like some have seen some additive benefits of adding all of the components together but it is hard to put a metric on each because of simutaneous changes to fuel pressure, cat deletes, X pipes etc.
Were you guys doing fuel pressure modes when dynoing the GT.... Many have mentioned that this should accompany any intake/exhaust mods. Sounds like you guys have a lot more practical experience than I. But headers shouldn't hurt. You will definitely have less resistance. Was there any benefit to area under the curve vs just hp max?
Here is a post I started in summer.. hopefully that link will work...
Is there an easy way to make a link? or is there an HTMl tag?
https://rennlist.com/forums/928-forum/201381-exhaust-headers-cats.html
As far as not seeing the performance gain expected from headers alone I would imagine that adding the X will give you a bit more because of the scavenging effect, Which headers alone will not give you. But your expereince with our GT sounde like one give you quite a bit but two not much more?
Do you have the dyno charts?
Sounded to me like the X is the cake.. headers is the frosting. That is given performance cost, availabilty, and effort to install. but hey I like cake and frosting!!!
Also I spoke to Jim after the above string and he feels that the original early style cast manifold are a major limitation, but the later style welded steel ones were not that bad... Opinions opinions... but this seems like sounds reasoning.
I had the crossmember out this summer and the engine being suspended by a hoist so I did not feel comfy letting it hang there any longer and the headers were not in stock. otherwise they would be in my car now.
Thanks for talking Tom I am from Redding originally so my home town is not too far south of you guys...
LO
That is interesting. Sounded like some have seen some additive benefits of adding all of the components together but it is hard to put a metric on each because of simutaneous changes to fuel pressure, cat deletes, X pipes etc.
Were you guys doing fuel pressure modes when dynoing the GT.... Many have mentioned that this should accompany any intake/exhaust mods. Sounds like you guys have a lot more practical experience than I. But headers shouldn't hurt. You will definitely have less resistance. Was there any benefit to area under the curve vs just hp max?
Here is a post I started in summer.. hopefully that link will work...
Is there an easy way to make a link? or is there an HTMl tag?
https://rennlist.com/forums/928-forum/201381-exhaust-headers-cats.html
As far as not seeing the performance gain expected from headers alone I would imagine that adding the X will give you a bit more because of the scavenging effect, Which headers alone will not give you. But your expereince with our GT sounde like one give you quite a bit but two not much more?
Do you have the dyno charts?
Sounded to me like the X is the cake.. headers is the frosting. That is given performance cost, availabilty, and effort to install. but hey I like cake and frosting!!!
Also I spoke to Jim after the above string and he feels that the original early style cast manifold are a major limitation, but the later style welded steel ones were not that bad... Opinions opinions... but this seems like sounds reasoning.
I had the crossmember out this summer and the engine being suspended by a hoist so I did not feel comfy letting it hang there any longer and the headers were not in stock. otherwise they would be in my car now.
Thanks for talking Tom I am from Redding originally so my home town is not too far south of you guys...
LO
Originally Posted by Tom. M
Hey Loren,,
Yes...we in the PacNW...realize that....but every once in a while we need to coax the Prof. out of his compound so others can benefit from his knowledge
Only reason I posted was to be devils advocate..in the sense that we've had GT's with stock manifolds and Louie's X....put down the same numbers as a devek level II header and modfied Ott X...
Now to pose another question..we've worked on a 83 with a 84 euro motor in it....equipped with msds headers....but the two sides never mated up...as in two pipes cats etc..back...its dyno numbers were not what was expected...so.....would a crossover after the MSDS headers help.?..or put it after the cats?...or a simple connection tube (ala H pipe)...and how much would he concievably gain by addding the above?..
thanks
Tom
89GT
Yes...we in the PacNW...realize that....but every once in a while we need to coax the Prof. out of his compound so others can benefit from his knowledge
Only reason I posted was to be devils advocate..in the sense that we've had GT's with stock manifolds and Louie's X....put down the same numbers as a devek level II header and modfied Ott X...
Now to pose another question..we've worked on a 83 with a 84 euro motor in it....equipped with msds headers....but the two sides never mated up...as in two pipes cats etc..back...its dyno numbers were not what was expected...so.....would a crossover after the MSDS headers help.?..or put it after the cats?...or a simple connection tube (ala H pipe)...and how much would he concievably gain by addding the above?..
thanks
Tom
89GT
10-09-2005, 04:16 PM
#74
Three Wheelin'
Originally Posted by Tom. M
Hey Loren,,
Yes...we in the PacNW...realize that....but every once in a while we need to coax the Prof. out of his compound so others can benefit from his knowledge
Only reason I posted was to be devils advocate..in the sense that we've had GT's with stock manifolds and Louie's X....put down the same numbers as a devek level II header and modfied Ott X...
Now to pose another question..we've worked on a 83 with a 84 euro motor in it....equipped with msds headers....but the two sides never mated up...as in two pipes cats etc..back...its dyno numbers were not what was expected...so.....would a crossover after the MSDS headers help.?..or put it after the cats?...or a simple connection tube (ala H pipe)...and how much would he concievably gain by addding the above?..
thanks
Tom
89GT
Yes...we in the PacNW...realize that....but every once in a while we need to coax the Prof. out of his compound so others can benefit from his knowledge
Only reason I posted was to be devils advocate..in the sense that we've had GT's with stock manifolds and Louie's X....put down the same numbers as a devek level II header and modfied Ott X...
Now to pose another question..we've worked on a 83 with a 84 euro motor in it....equipped with msds headers....but the two sides never mated up...as in two pipes cats etc..back...its dyno numbers were not what was expected...so.....would a crossover after the MSDS headers help.?..or put it after the cats?...or a simple connection tube (ala H pipe)...and how much would he concievably gain by addding the above?..
thanks
Tom
89GT
A crossover would definitely help, both in power and make a smoother sound. A simple H in front of the cats would be ok, or an X after the cats. If using an H, use as large a cross section pipe that will fit. All of the installs I am aware of where the cats are behind the X have had trouble with the cats not getting hot enough to light without wrapping the pipes ahead of the cats, or ceramic coating, or both. That was with my long X. Using a shorter X may allow enough heat to be retained to light the cats. Using stainless pipe would help because it doesn't conduct heat as well as mild steel. To sum up, cats ahead of the X will work better for smog, cats behind the X will be better for performance. I sure don't have a clue as to how much gain can be had from a crossover of any kind with MSDS headers, but it should be worth persuing.
One other thing.... I replied to a post last night regarding using a 3" pipe X crossover with Devek headers and said you'd need a tapered transition piece to go from the 3.5" collector to the 3" X pipe size. The Devek header collector is not 3.5". It is 3" so if using a 3" diameter exhaust no tapered transition is necessary.
10-09-2005, 06:11 PM
#75
Hi Louie,
That is interesting.
Do you think that X before Cats will still pass smog. Sounds like most people are using random tech... is that you recommendation. Interesting that you also recommend using more heat conductive materials to make the cats work right.
Also I have heard that modern cat cores do not require the air injection as a source of O2... just to get warmed up as you mention. Do you delete the air pump for mo power and mo room in the engine bay.
Yipppee!!! I just drove the car for the first time in a month... I fixed a big oil leak at the filler neck... powder coat problem... And I put the devek oil baffle/gasket peice... my stock one was a little spit on the edge... I used DC111 silicon to seal the leak and it seem to be holding so far!!!
Now it is time it clean off and look for the next leak! F@^%!
Thanks,
LO
That is interesting.
Do you think that X before Cats will still pass smog. Sounds like most people are using random tech... is that you recommendation. Interesting that you also recommend using more heat conductive materials to make the cats work right.
Also I have heard that modern cat cores do not require the air injection as a source of O2... just to get warmed up as you mention. Do you delete the air pump for mo power and mo room in the engine bay.
Yipppee!!! I just drove the car for the first time in a month... I fixed a big oil leak at the filler neck... powder coat problem... And I put the devek oil baffle/gasket peice... my stock one was a little spit on the edge... I used DC111 silicon to seal the leak and it seem to be holding so far!!!
Now it is time it clean off and look for the next leak! F@^%!
Thanks,
LO