Since I receive a lot of mail about the adjustability of Dave's header and exhaust system, I thought I would give the latest update. One of the main selling features to the SMSP design is the flexibility one has with the adjustable primaries, secondaries, and collector design. Yesteerday I installed my first set of header extensions and thought I would give my impressions.

Here are the extension. They are of a slip-fit design just as the header is. Total length is around 4". This will effectively lengthen my primaries by 2" over the current set-up.



I attempted to remove the secondaries while the header remained on the car. Unfortunately, I was not able to. To remove them I needed pull them and this was just not feasible. Removing the header allowed me to used a rubber mallot on the primaries to loosen them. This was a very simple task to perform and excess pounding was not necessary. Here are the extensions added to the primaries. I painted them with a high-temp paint to prevent rusting. *Toes are my roommate's*



Here is another angle.



Here is the entire header re-assembled.



Here is the underside. My tubing pinch bolts were now too short so I need to find some replacements. Jeff (Lip) made a nice recommendation earlier to me about using battery tie-down bolts. Seems this is what he used on his HiTech after the same problem was found. The stains around the joints are just from some anti-seize I used at initial assembly and wipe off easily.



At the same time, I installed my SMSP test-pipe. Here is a comparison pic to the CarSound cat Dave offers. With my adjustable exhaust system I was able to lengthen the header extremely easily. With most applications I would have had to have the B-pipe modded to make this change. The sliding B-pipe feature allowed me to just swap the cat for the pipe and bolt it up at the correct length.



End result: The car pulls extremely well with the new mods. As we proved in my dyno plots a few weeks ago the test-pipe only offered the slightest advantage over the CarSound (2-3 whp peak). I chose to make this change for consistency in some upcoming tuning I have planned. I have noticed the the tes-pipe has caused the exhaust note to become a bit more "rapsy". Seems the cat provided a nice muffle to the exhaust note. I would like to stress that this entire install took about 3 hours in total. A fairly quick process considering I've only done this procedure only one other time, at installation. Please let me know if you have an other questions. I will be posting my plots with the extensions once testing is done.

 

Sweet pics. Are you going to thermal coat the extensions as well? Do you have any pics of the modified B-pipe with the sliding extension?

 

I may get the extensions coated in the future. Why waste money if the extenders are not the correct length! I am just starting to play with adjustability in the header length. Once I get everything dialed in, I probably will.

Here is a quick pick of the pre-production sliding B-pipe.



Here it is installed with the cat.

 

Cool,

Are you running the SMS 2.5 inch mandrel exhaust with Magnaflow muffler, or is that someone else? I'm hoping for this whole setup (header, cat, and exhaust) in the Spring, but I was hoping the system does not sound raspy? I would use a carsound cat (94006, right?).

Right now I have a 3 year old Greddy exhaust with RT Cat and it sounds like ***. Very obnoxious and loud with a lot of raspiness. I'm hoping the new system would be deeper and clean sounding, but my primary concern is picking up 10+ HP

Also, as a general question, is the theory that lengthening the primaries results in more TQ/low-mid and more area under the curve?

Thanks,

FB

 

Berkel~

Yes, I am the test car for the SMSP exhaust system. The seet-up is not raspy at all with the CarSond cat in place. The test-pipe is raspy! I dyno tested both and and the cat only gave up 2-3 peak whp. Not very much to remain legal in my opinion! I only re-installed the test-pipe for comparison testing.

Your also right on lengthening the primaries. I have a slight dip in power around 4000-5300 rpm. By lengthening the primaries I should be able to eliminate this. Good observation!

 

The car sounded good at Rockingham...........I have it on Tape.

Under street conditions RStoR's set up was nice sounding and looks "STOCK."

If you don't know anything about cars or ITR's, you would think it was stock........or as we all call it SLEEPER!

 

damn it, chris . . . every time i see a pic of that adjustable b-pipe, i start lusting for one!

like franz (berkel), i'm going to have to get one of the SMSP 2.5" 'stock' exhaust systems next spring. i just SMSP'd my stock b-pipe, and with the JDM 4-1 header and 96006 2.5" carsound cat, i am restriction-free and loving the quietness! (just took off my 60mm thermal 'loud-***' exhaust.)

is dave planning on producing a s/s system, or is it going to be aluminized and high-temp painted?

thanks!

peter

 

Heh Franz your car doesn't sound THAT bad...

 

The systems will probably be all stainless tubing in the future. Still not sure if I'll go with the liter weight 18g tubing or the heavier 16g. I'll probably have to test 2 similar systems with just different tube thickness. My gutt tells me the 16g MAY BE a little more quiet due to its greater mass. But, who knows this may just be BS. Aluminized...maybe. Mild steel.. I don't think so, due to its limited life span.

? on tube extensions: These should be stainless so you don't have to worry about coating them after they are cut to length. RStoR got the mild steel ones since I didn't have any made up in stainless at the time and we were hoping to try them at his last dyno test.

 

Heh,

Thanks Ross, but I think it's getting worse...

Actually, the sound is more of an excuse to sell getting a new exhaust to my fiancee. "See how bad my exhaust sounds? I need a new one."

Car is running much better after richening and setting cam gears to +3/+1. Check the post in the DFH forum for the tuning results,

Take care,

FB

 

s/s? excellent! also, dave . . . i know chris' (RStoR) prototype exhaust featured his stock polished exhaust tip . . . what kind of tip are you planning on using?

thanks! i'm looking forward to the full s/s exhaust!