Long tube header results!

[ed94r]

I bought these from a vendor on BFc for $215 shipped. They are the Supersprint replica's. It took some work installing them (had to remove the motor mount/arm to install front header and cut midpies to fit) but they don't interfere with the subframe, sway, or stock lollipop's. Thought I'd post our results...Oh, and nothing was changed or altered from my baseline (the blue line) except the header.

Looks like I gained (the header is runfile 4 *red*) about 4-5 rwhp and rwtq with no loss in low end Torque. If you notice, I picked up almost 10rwhp @6600+!!

AFTER we dyno'd, we worked on "opening up" the stock OBD1 midpipe 2 into 1 merge collector. We cut the section out, brought it to a muffler shop and opened up the *pinch* where the two pipes merge using a pipe expander. This REALLY free'd up the car. I wouldn't be surprised if I picked up another 10 rwhp by doing this. I felt more of a seat of the pants power surge with doing this than bolting on the headers and I made 5 rwhp with the headers! It was too late to re-dyno it, so it's in the plans...

Also, the stock OBD1 manifolds and downpipes (the part of the midpipe I didn't use) weighed 26lbs. The headers are 13 lbs!

Don't focus on the actual rwhp #'s, just on the differences. The same car dyno'd 226/230 on a DynoDynamics (a different dyno and location) about a year ago, so on *that* dyno, I would probably put down 230/235 rwhp/rwtq with the headers. I recommend these headers.

Ed

[cheades]

How long after the first dyno on the graph was this dyno? Were they the same day or atleast close, I hear there can be a 5hp difference just in a day or two at the same dyno.

[1990m3]

nice results. I am definitely getting these for my car in a few months and working them into the system.

What muffler are you using?

[tonytony]

i should have bought these headers when i had the money shitty for me, good for you! What engine do you have?

[Ferret]

Can you post some pictures of the headers and the mid pipe collector?
Thanks,
Avner.

[KangamangusDriver]

Wow that is impressive!

What mods do you have to the S50?

I would like to achieve those numbers or higher!

[SchnellerVert]

93 degrees the first run and 78 the second run. That alone can make some of the differance.

The weather factor should be at least semi close.

[Addiction2E30s]

Due to the weather differences, this is not an accurate comparision. 14 degree cooler weather can easily produce 5 rwhp.

[ed94r]

The dyno is a 424xlc2, the latest and greatest from Dynojet.

The SAE corrections will *to a point* even the score over temperature/altitide differences. On a normally aspirated car, sitting on the rollers, in the shop...after a few pulls is going to reach the same approximate operating temp. Air inlet temp (hard to control with a hood that opens the wrong way for a cooling fan) makes a bit of difference in making power, but will not effect the actual *curve*. The motor IS making more power, but most significant of it is after 6K.

The reason I posted the resut is because most folks believe aftermarket headers make no difference...heck there are those that say you LOSE power with the aftermarket..specifically loss of power down low with a slight boost up high. That did not happen at all in my case. One thing is for sure (now that I know), I wouldn't do the headers WITHOUT pressing out the pinch at the collector. The pinch is where the *real* restriction is...less so the header. It's really necked down at that spot. Out of all the mods I've done to the motor...removing the pinch make the most difference IMHO.

I will bring it back to dyno the full completed exhaust soon. I am confident I'll make even more power.

I don't have any pictures, other than pics of headers already on the car. Next time I get it in the air, I take a few snaps.

Ed
S50 (CNC intake) , 3.5HFM, 21.5#, AA chip, Pullies, Fan delete, CAI, catless 2.5 exhaust

PS: I am no expert, but isn't (1) horsepower for every 10 degree of ambient temp the standard? 14 degree difference is 1.4 horsepower..not sure if this is applied at the crank or wheels. (?)

[Ferret]

I don't have any pictures, other than pics of headers already on the car. Next time I get it in the air, I take a few snaps.

That would be great.

[Adrian_Visser]

yes yes with some pics of this pinch area and what u did to fix it plz

[Rev Engineer]

Do you think you'd see even better results with a obd ii midpipe?

Have you seen this analysis between the 95 and 96+ cats?

http://www.rogueengineering.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=CATS

[ed94r]

Do you think you'd see even better results with a obd ii midpipe?

Have you seen this analysis between the 95 and 96+ cats?

http://www.rogueengineering.com/Merc...gory_Code=CATS

I think the hot ticket would be the long tubes (2" after the collector), flowing into dual 2" mandrel bent pipes all the way back (using a 2in2out resonator and muffler) or like BMW332i did, dual individual cats into a 2into1 muffler. I forgot who, but there is a mfg. that make a 2in2out resonator with an integrated X pipe inside the case...Saw it in Summit's catalog. That would be IT.

That being said, I need to dyno the car to see if we can conclude that expanding the OBD1 collector makes a difference...I suspect we'll all be in for a big surprise. I really don't like the idea of the OBD2 midpies b/c they are dual walled, therefore hard to work with (read: PITA$$$) to get them adopted to the headers. I like the 2 into 1 setup..simpler and it saves a good deal of weight. If someone does expand their OBD1 pipe, it would be cool if they measured it so we can calc the *improved* surface area of the modded pipe. I didn't have the time.

I had planned to do a Flowmaster 2into1 merge pipe, ridding myself of the whole OBD1 enchilada. With the way the car has been running after expanding the stock merge...I'm not gonna waste my time.

Ed

[tonytony]

i dont understand the pinch you're talking about ed. Are you talking about how on the stock e30 exhaust it's flattened out so there would be clearance?

[ed94r]

If you click on the link Rev Engineer provides a few post's above, you will see the two options you have when you do the conversion if you want to use BMW stuff and not custom.
1. OBD1 midpipe (2into1)
2. OBD2 midpipe (2into2)

The OBD1 midpipe merges from 2into1. It's not the *merge* itself which is restrictive...it is the *pinch* after the merge which *is*. It looks like an indent in the pipe.

I talked to my man at the shop today, and I was told that there are 2 different OBD1 2into1 collectors. One for the E36 325's and one for the M3. I have the M3 one's and they were pinched. I was told the 325 collectors are even narrower. Since I have not personally seen the 2 side by side, I cannot offer this as fact. RealOEM has 2 different part #'s for the OBD1 midpipe...(?)

None of this stuff is carried over from the E30 exhaust.

Ed