[NickD]

Hey guys. I was talking with my machinest Saturday morning. We were discussing a number of performance options and he highly recommended installing a set of headers. I told him how much I would really love to do that if I could but as of now none were available. Then I mentioned some are possibly in the works but they would shorty headers. He then says I could send my current exaust manifolds to Extrude Hone and he said on mine they could increase flow up to 70% which wouldn't be that far off a set of shorty headers. The cost appears to be $500 for a V6 engine, which comes out to still be cheaper than headers. I haven't had a chance yet to call extrude hone, I will probably call them tomorrow.

Does anyone know anything about this process aside from what's on their website? (http://extrudehone.com) I am very seriously considering this.

I know DaveC knows some stuff. Everytime I mention P&P infront of him he quietly mentions Extrude Hone... hehehe

 

[Mckenzie93]

I am absolutely no expert on this nor do I know about what the gains could be. However I have heard very good reveiws on this company and that thier work is top notch. I was too in your boat Nick...... knowing that I had to rip my engine apart and I wanted something done while it was in peices. I was talking to a performance shop and they recomended either a port and polish or extrude hone. It does exactly what you say.... free up air flow and it reduces friction/turbulence/resistance. I say go for it and let us know of the gains.

 

[CWA-94GS]

I bought a set of manifolds at a junk yard with the intention of seeing what the problem was and if they could be improved. I am building a flow bench but it is no where near finished. I did some uncalibrated tests with some quick setups that I hacked together. I think porting the manifolds would yield some improvement. I think the main problem with the manifolds is uneven flow. I think the flow from port to port is not even because of the way it spills into the chamber. I think a set of untuned shorty headers would fix this. I think they would be fairly easy to design and build at a reasonable cost. I am going to build some potential designs with junk from Home Depot and flow test them when my virtual flowbench becoms reality. Another thing I noticed is that the O2 sensor is right in the middle of the flow path. I think this adds restriction but I have not been able to prove it. I am thinking of a possible mod that would take it out of the flow path. These are my own unproven thoughts. IMHO you are better off waiting and putting the money into a better manifold design.

 

[Dv8]

It may yeild some + but unless you seperate the exhaust ports, i.e. individual exhaust port tubing your optimum wont be achived.

However way you work it, a +will be achived.

Long tube header design is the best and capable of 40+WHP/nearly impossable to fit without taking the engine out+ $2k


~Hybrid

 

[502 MotorSports]

It may yeild some + but unless you seperate the exhaust ports, i.e. individual exhaust port tubing your optimum wont be achived.

However way you work it, a +will be achived.

Long tube header design is the best and capable of 40+WHP/nearly impossable to fit without taking the engine out+ $2k

~Hybrid

Hey Christian, where do we stand on the headers?
I would love to slap those puppies on after NOPI

 

[CWA-94GS]

I agree with DV8, that tuned long tube headers would be best because they will produce more gains in the low end, but I think the short tube header would provide decent gains because of the separate port tubes. The shorties seem like an easier project. Not as good as long tube, but when used in conjunction with other good mods, it would produce decent results.

 

[Dave C ver2.0]

You're never gonna kit equal length tubes into the G2 chassis. It is just to tight and having the half shafts in the way only makes it worse. I had a shop working on a set of shorties and the guy gave up because they were taking to much time to fit up. Still looking for another shop that will tackle the job, but most take a look from underneath and say no thanks. Hope Dv8 is having better luck.

 

[NickD]

DaveC, That's pretty much what my machinest said when I showed him what I was up against. So I think, at this point in time, being that my engine is completely apart and I can't physically get the car to a place to have headers, shorty heads or anything of the sort made shipping my exaust manifolds out to Extrude Hone would probably be a good solution?

I am going to call them later this afternoon. The pricing on their web page shows $500 for exaust manifolds on a V6 but the pricing is outdated, being posted on October of 1999. Does Extrude Hone have any competitors?

 

[Dave C ver2.0]

You'd have to confirm the price with them. As far as I know there is no one else doing this type of work. Cost is high because of the setup work that needs to be done for each piece.

 

[infinite]

It may yeild some + but unless you seperate the exhaust ports, i.e. individual exhaust port tubing your optimum wont be achived.

However way you work it, a +will be achived.

Long tube header design is the best and capable of 40+WHP/nearly impossable to fit without taking the engine out+ $2k

~Hybrid

I thought you had said that only the heads would need to be removed to get the long headers in.

 

[NickD]

I spoke to Extrude Hone today. $500 for the exaust manifolds, 2 weeks turn around time, ~20% increase in flow and will yielf 15WHP.

So now the question remains, how will this effect the rest of my porting and polishing and the custom exaust system I am putting in... :-/

If it doesn't, is $500 for 15WHP (~18 crank) worth it???

 

[LegendGS]

According to Christian, he was able to get 7 whp out of the Bayou chip. Being that the group buy price was around $250-$300, $500 for 15 whp doesn't seem too bad.

My question is how do they determine how much HP that job will provide to the Legend?

 

[Dave C ver2.0]

Previous experience?

 

[CWA-94GS]

Nick,

Did they tell you how they came up with those numbers, and will they provide you with proof of a 20% increase in airflow. Since the exhaust manifold is in the middle of the airflow path, horsepower gains would vary depending on your other mods.
The rule of thumb is 1.6 CFM per horsepower (correct me if I am wrong) which means for a type II (230*1.6), the airflow is 368 CFM. A twenty percent increase in airflow would be 441.6 CFM. If we assume all else is ideal, the theoretical hp would be 441.6/1.6=276HP. The 20 percent number seems optimistic, but if it does provide 15hp, that wouldn't be bad. I'm still skeptical but it might be worth a try.

 

[LegendGS]

Previous experience?

Previous experience with the Legend on the Dyno, basic rule of thumb, mathematical formula like CWA-94GS mentioned, or raw guesstimate?