Headers: Evosport vs. Renntech?
I didn't see any posts that compare actual performance gains of the two header designs, but the consensus seems to be dependable gains of 25-30HP and maybe 30-35 ft. lbs. of torque from either on an otherwise stock engine.
In looking at the available of photos of each, I note the following:
Renntech:
1. About $1,000 more expensive
2. Stainless steel tubing, mandrel bent, non-segmented
3. 4-2-1 design
4. non-coated
Evosport:
1. About $1,000 less costly than Renntech
2. Tubing is aluminized steel, not higher quality stainless
3. Tubing is mandrel bent, but each primary appears to be two or more segments butt-welded together (not seamless)
4. 4 into 1 design
5. high temp thermal coating
So it looks like each has some merit. Renntech uses higher quality materials, but I don't know if their design is superior to the Evosport design or not. They're much more costly per on a HP/$ basis.
Evosports are made with cheaper steel and have butt-welded primaries, which are not optimal for flow. But they do have coating and may have a better design for flow purposes. Plus, they're less expensive on a HP/$ basis (assuming they produce as much HP as the Renntechs).
So for me, it would probably boil down to which set actually FITs the best and installs with the most ease. I don't want to end up having to lift the engine or having to remove a bunch of stuff to install them. Has anyone personally installed them that can speak to this? Any other factors to be considered (ignoring cost)?
Last edited by viper04; Jan 12, 2007 at 06:07 PM.
There's a Mercedes tax which is higher than a BMW tax, and there's a Porsche tax which is about equal to the MB tax but the Ferrari tax is higher than the Porsche tax, Lambo tax, Bentley tax, the list goes on.
All of these taxes are way higher than the Chevy, Ford or Dodge taxes.
It's your choice.
There's a Mercedes tax which is higher than a BMW tax, and there's a Porsche tax which is about equal to the MB tax but the Ferrari tax is higher than the Porsche tax, Lambo tax, Bentley tax, the list goes on.
All of these taxes are way higher than the Chevy, Ford or Dodge taxes.
It's your choice.
Guess what Im saying is I need to get on the ball and have some sets made for our cars at a better price.
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Not to mention there are alot more Vettes being built than E55's, more available sales also helps support a cheaper price.
If Hooker can sell 10,000 headers a year to vette owners and Renntech can only sell 1000 headers then Hooker can sell them much cheaper.
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I didn't see any posts that compare actual performance gains of the two header designs, but the consensus seems to be dependable gains of 25-30HP and maybe 30-35 ft. lbs. of torque from either on an otherwise stock engine.
In looking at the available of photos of each, I note the following:
Renntech:
1. About $1,000 more expensive
2. Stainless steel tubing, mandrel bent, non-segmented
3. 4-2-1 design
4. non-coated
Evosport:
1. About $1,000 less costly than Renntech
2. Tubing is aluminized steel, not higher quality stainless
3. Tubing is mandrel bent, but each primary appears to be two or more segments butt-welded together (not seamless)
4. 4 into 1 design
5. high temp thermal coating
So it looks like each has some merit. Renntech uses higher quality materials, but I don't know if their design is superior to the Evosport design or not. They're much more costly per on a HP/$ basis.
Evosports are made with cheaper steel and have butt-welded primaries, which are not optimal for flow. But they do have coating and may have a better design for flow purposes. Plus, they're less expensive on a HP/$ basis (assuming they produce as much HP as the Renntechs).
So for me, it would probably boil down to which set actually FITs the best and installs with the most ease. I don't want to end up having to lift the engine or having to remove a bunch of stuff to install them. Has anyone personally installed them that can speak to this? Any other factors to be considered (ignoring cost)?
3. Tubing is mandrel bent, but each primary appears to be two or more segments butt-welded together (not seamless)
The reason for aluminized steel is twofold - stainless is more expensive and has a tendency to crack when bent very sharply after a number of heat cycles.
Also to create one piece tubes for each would add to the cost of the headers. Each set is built on individual order basis and is done by a professional fabricator to assure quality and consistency.
I will believe you on the cost saving issue, but not the quality of material issue. Nonetheless, thanks for making a direct fit option to the Renntech offering available.
OEMs use softer 4-series stainless steel.
Most fabricators use 3-series stainless steel that is harder and more prone to cracking.
My opinion is based not only on theory, but also on experience of working on and tuning a lot of cars. Many with aftermarket stainless steel headers.
Even Supersprint is not immune from it, just search BMW forums and you will see what I mean.




