Exhaust Systems - Pros/Cons

[builder]

Seems there's a lot of recurring questions and options for headers, cats, silencers, exhaust pipe, coatings, materials, shape, up/down, etc., for different engines. So, I thought maybe start a thread that might turn sticky.

Please post pictures of your exhaust system along with a description of the system and engine type.

Mine will be a Chevy LS7 with stainless 1-7/8" primaries and ceramic coating. Not sure of the design shape yet. Not sure on the silencers. <insert photo here>

[crafty]

Scott,

I asked Kurt Dobson (Spectrum 5) about ceramic coating to SS and he said it wasnt necessary as SS inherently holds the heat in. He says the ones he builds for NASCAR teams dont use coating. At that level of racing every little bit helps, which is why they use his headers which are tuned and exactly equal length. He sells those headers for USD28K per set so I am guessing that if they pay the extra for the headers they'd go for the coating if it made a difference...

I'd be interested to see any installs of headers on LS engines, particularly if they run down low rather than over the valve covers...

Also, there is an excellent guide on LS1tech which is worth a look. Coincidentally I found this yesterday - www.ls1tech.com/forums/showthread.php?t=139142

>> Edited by crafty on Tuesday 10th January 00:46

[builder]

Chris,

That's a boat load of green-backs for an exhaust! Good reading on the link.

[bigmack]

You should see the price for the engine modeling software that he uses! I would definitely trust anything that he's designed.
Cheers!
-Mack

[crafty]

Kurt's Ultima exhaust system is USD6995 including two sets of "up-pipes"... one with cats and one without - USD395 extra for polishing.

Yes that link is good reading...

Photos below:

1) With Cats - un Polished
2) Without Cats - Polished
3) Without Cats - Polished

[BigMack]

Good God! $7 grand for exhaust! No wonder he didn't email me back when I enquired about the cost of that setup! How many has he sold I wonder? That's pretty insane.
Cheers!
-Mack

[crafty]

I know he's done 4 like this for LS engines, and one slightly different for an LS engine. I think he did a few SB ones for Brammo also....

Now - for comparison:

$100 = Flanges - 2 @ $50
$540 = Merge Collectors - 2 @ $270
$240 = 1 3/4" U bends - 8 @ $30
$240 = 1 3/4" U Straight - 8 @ $30
$510 = 3" U bends - 6 @ $85
$360 = 3 "Couplings - 2 @ $180
$300 = Cats - 2 @ $150
$500 = Mufflers 2 @ $250
$3000 = Labour - 60 @ $50
$5790 = TOTAL

- that's all assuming that you get all the bends right the first time and dont have any waste!!! and also remember that the one from Kurt is an engineered item....

For reference on the Material see -
www.burnsstainless.com/Burns_Catalog/Burns_Catalog_2005_Final.pdf

For reference on the labour - Mark Koch 95 hours, but his is turbo



>> Edited by crafty on Wednesday 11th January 05:30

[ezakimak]

you missed an extra set of 3' couplings, wasn't Kurt going to supply a set of up pipes without the cats as well ?


>> Edited by ezakimak on Wednesday 11th January 05:52

[BigMack]

Still sounds like a lot. Especially when you consider that this is for a street car and not a race car. Then again the exhaust is sort of a showcase for the vehicle. So I guess it doesn't hurt to dress up this area of the car. I'd expect a $30k engine to go along with it though.
Cheers!
-Mack

[crafty]

You can't buy off the shelf items. The factory ones would not be a good idea with all that heat up high (esp with an LS engine - if they fit) ..... so the options are stock cast iron manifolds (which would not do the engine justice), get headers fabbed, or Spectrum 5 items... I rekon getting them fabbed is not worth the risk to save a grand.

[crafty]

hmmmm....that's got me thinkin'.... I wonder if the factory ones could be swapped left-to-right and mounted the other way to make an exhaust that sits down low and hugs the block (like Spectrums)....... maybe need new flanges and a bit of welding to adjust for the angle of the heads when used this way around...but for the price it might be a good start.

I will investigate and get back on this.... need to check exhaust ports SB vs LS and angle of ports...

[cymtriks]

Tech Question

All designs shown are 4 into 1 per side.

IIRC that's supposed to be not the way to do it?

I thought for a V8 you could-

1) connect cylinders at 360 degrees to each other as on the Ford GT40. The cylinders at the ends of one side connect to the cylinders on the middle of the other side. This is a 4 into 1 design, only crossing side to side on the engine.

2) connect cylinders at 270 degrees to each other. This keeps the two sides separate so greatlty simplifying over (1). This is a 4 into 2 into 1 design with no crossover between sides. typically on one side cylinders connect 1+2 and 3+4 and then join into one while on the other side they connect 1+3 and 2+4 and then into one pipe.

3) any other way isn't optimal for power.

Marquis Rex posted a very good bit of info on this subject some time ago. He should know, he worked on the Jag V8s.

[eliot]

Might also be worth looking at after market turbo headers, as the ones ive seen are high up and go fowards like the ones in the pictures above.

[crafty]

I just did a quick play around on ACAD - got myself a 3DCAD drawing of a small block, did a very rough sketch of one of the factory pipes. The red one is the std one and the blue one is switching left-to-right. Flanges definitely need re-welding.

Can someone check these dims for me... Factory??

EDITED - forget it - the exhaust ports setout is completely different - far to much work.

Spectrum 5 still gets my vote.




>> Edited by crafty on Wednesday 11th January 14:08

[chevtrev]

Not in a Ultima but pretty similar to Spectrum's.
Equal lengthed 1.7/8" SS on a LS6,custom made, 3000NZD about 1200UKP

[BigMack]

Well, I'm not saying Kurt's setup isn't worth it. After all, I spent $8-10k on the brakes! Ha. Just a bit of a sticker shock when your used to seeing prices for headers and exhaust from reputable companies for other cars and race cars. I'm surprised that no one has taken their car to someone like Stahl, Schoenfield, Hedman, or even flowmaster. I've seen the exhaust routing a few different ways. I've seen a prosports(very similar to Ultima) come out sideways and wide to get extra length in the headers. Into the side pods. Jeff Schwartz went down low with his headers. I've always been a little concerned with heat right next to the transaxle, but there is quite a bit of air coming into the engine bay from under the car. Most of the race cars(Ultimas, Prosports, and Stealth) have the headers and exhaust up high. LIke in this photo. A little hard to get to the valve covers when you want to check valve lash though.
I have the factory exhaust on a standard Chevy. I went cheap and bought the mild steel ones and now they are pretty rusty. I'm looking for something in stainless, but I really don't want to spend $5-7K for it. I've looked at boat headers that go up high. Kurt's look like "block huggers" and come down somewhat low but not below the oil pan. I can understand your dilema though crafty.
Cheers!
-Mack

[peterpsg]

I don't see any cross over pipes, are they disallowed in competitions or are they just overhyped exhaust note modifiers ?

[crafty]

Some more stuff:

I have posted a load of photos from Kurt on my site - (jan 12th 06) There's too many to post here. As you can see, if you run the exhaust low it must be done very accurately as the gap between the chassis and the engine is not so large. http://spaces.msn.com/members/ultimaGTR/

Ultima with a ford engine in OZ...This must be a Windsor engine (60 degree Vee) 'cos its very narrow.

[BigMack]

This has turned into an ironic topic for me. I've been preparing my car for a track day at the Texas World Speedway. I pulled off the exhaust b/c I thought I might have time to sandblast and paint it. I have the mild steel version. I'd forgotten what a pig of a job this is! Pulling off the exhaust was easy, but installing it is a bloody aweful job. These things have never been easy to install as the header flanges don't line up at all. Having purchased and installed headers on other cars, I'd have to say that I am pretty dissapointed with these things. I hope the factory are selling a better version of headers now. I wrestled with mine for 2 or 3 hours and still lack one stupid bolt to having them completely installed. After my track day, I'm going to inquire about getting something made here in the states with a one piece header flange. If the headers never had to come off then that would be one thing, but its so much easier to inspect things with them off.
Will keep you all posted.
-Mack

[pb3]

My stainless system also has individual flanges (3 in total on each header) but I know the factory stopped doing them in favour of a one piece design quite some time ago. I only had issues with fitting the headers from new the first time round, I guess I have been lucky that on the several occassions that I have taken them off they went back on "quite" easily, but in life there is always one...