Possible SVX header

[mbtoloczko]

Chike, I think its necessary to consider perspective when looking at what works with the V-8 people. With the exception of the newest V-8's, most factory V-8 exhaust manifolds do not flow particularly well, and there is significant exhaust flow overlap between cylinders on the same side of a V-8 engine, so even a shorty header can provide smoother flow and some improved isolation between cylinders. OTOH, our factory SVX exhaust manifolds have a nice smooth flow pattern, and there is no exhaust flow overlap between cylinders on the same side of the engine. I think that the only thing that an aftermarket header can provide for the SVX is tuned scavenging which requires primaries that are at least 36" long to provide any scavenging in the useful part of the powerband.

[Chiketkd]

Tom,

I don't feel any of the bends in the Outback Motorsports mandrel bent headers are that sharp (the bends in those 5.7L Edelbrock shorties are sharper). Also, our stock exhaust manifold has a few that are quite sharp. I would agree that the rest of the exhaust will need to be altered, but I'm not ready to give up on this idea just yet.


Mychailo,

I agree that the stock V-8 headers aren't the most efficient. How efficient are the factory SVX headers at stock power levels (I think someone mentioned they were around 95%+)???

I'm just thinking with my cams and other upgrades, these primaries could flow better than stock and produce some +ve gains. I'm also wondering if those claims by Stebro were in fact true.

-Chike

P.S. However, it seems from the discussion taking place in the n/a upgrade thread more gains can probably be made from a better intake system.

[Chiketkd]

Okay, I spoke with the owner John at Outback Motorsports and those primary tubes are designed for a dune buggy - the flanges match up with the EG33 and will be a direct fit to our engines, but he thinks it'll butt into a motor mount or something (never tried to test fit it to an EG33 that was still in the SVX).

He was really nice and said that the pair of EG33 headers are sold for $250.00. However, he thinks that for a street application, it would be better to have custom ones made. He's willing to sell the flanges that fit up against the motor and even the pair of 3-into-1 collectors seperately.

Here are the specs for his dune-buggy primary tubes:

1 5/8" ID primary tubes leading to the 3-into-1 collector that exits as a 2 1/4" ID pipe. On a stock EG33 dune buggy he normally sees 270-280hp with his primaries.

-Chike

[SVXRide]

Chike,
Nice stock manifold pics
I see you found Outback. The guy who blueprinted my injectors and rails told me about them - he does all their injector work. Outback also offers a braided steel line to connect our fuel rails, it you're interested.
-Bill

[Chiketkd]

Originally Posted by SVXRide

Chike,
Nice stock manifold pics
I see you found Outback. The guy who blueprinted my injectors and rails told me about them - he does all their injector work. Outback also offers a braided steel line to connect our fuel rails, it you're interested.
-Bill

Oh yeah, those stock manifold pics in your locker were very handy!

Looking at the exhaust layout behind the exhaust manifold:



I really doubt those headers will butt into a lower subframe. I may just go your route Bill and get a spare set of stock manifolds, have them sand blasted and then send them out for an extrusion and temp coating.

However, those Outback Motorsports 'shorty' headers look sweet!

-Chike

[SilverSpear]

Originally Posted by Chiketkd

He was really nice and said that the pair of EG33 headers are sold for $250.00. However, he thinks that for a street application, it would be better to have custom ones made. He's willing to sell the flanges that fit up against the motor and even the pair of 3-into-1 collectors seperately.

But i would prefer buying the headers as they are and perform the necessary changes if any appear other than lengh extensions.
On the other hand, did you get the chance to ask him about the price of the flanges and 3 to 1 collectors as they are Chike? or same price?

[Chiketkd]

Originally Posted by SilverSpear

But i would prefer buying the headers as they are and perform the necessary changes if any appear other than lengh extensions.
On the other hand, did you get the chance to ask him about the price of the flanges and 3 to 1 collectors as they are Chike? or same price?

They're cheaper he said but I didn't ask him for a price. Thing is I don't want to run 2 1/4" pipes back from my headers... That's just too big IMHO.

-Chike

[svxfiles]

A few header basics;
Out exhaust ports in the heads are 1.5".
They ( the exhaust ports at the head surface) are about 4" from the back of the exhaust valve head.
From my reasearch, we need 1,5/8" Inside Diameter primary tubes.
For a NA, turbocharged, or Supercharged engine, WITH THE STOCK CAMS, 1,5/8" about 30" long for the primary tubes/pipes is/was the correct length from about six different sources.
The longer the primary tube, the better the power at lower engine speeds.
The shorter the tubes the higher rpm maxium torque is reached.
Collectors should be about 2,1/4" ID and the length is argueable.
For an expantion chamber effect it should be ten times the volume of ONE cylinder displacement.
Equal length primaries, and MANDREL bending is very important, and hard to do.
Keeping the heat inside the headers and exhaust system raises the speed of sound, and helps speed the flow of exhaust out of the cylinders!
This is why ceramic coatings, OR stainless steel headers/exhaust systems are better than conventional mild steel systems.
And not just pretty.
I have made two sets of headers, and am happy with the performance of the second, equal length set, but ground clearance is lost, and unless it is coated, heat is lost at the expence of power.
Pictures are in my extensive locker.
More later, Tom

[SVXRide]

Originally Posted by svxfiles

A few header basics;

This is why ceramic coatings, OR stainless steel headers/exhaust systems are better than conventional mild steel systems.
And not just pretty.

More later, Tom

amen, Brother Tom!




-Bill