I have a cut out. Will opening the cut out lose, gain, or have no affect on power. Will having the cut out open cause a drop in exhaust pressure and slow down the release of exhaust gases, or will it allow for higher exhaust flow? I know it will be louder with the cutout open, but I'm more interested in its affect on power.

 

IMO, you should gain power across the board (low end, and especially top end).

Here's a little factoid for ya ...

... my Dad's '73 Camaro at the track. We ran a few runs in the 13's (13.2's - 13.6's) around ~103 - 104 mph. Then we opened up the exhaust, and ran wide open headers . 12.7 @ 109.72!! We ran 2 back-to-back runs (one, the time sucked) and both runs the speed was up a solid 5 mph! The #'s don't lie ... speed = power .

 

cutouts are not praised only because of their sound...you'll gain power. proven fact.

 

some old schoolers think you lose torque, but on my run after i had one installed i gained 9hp and 5'/lbs.

i hate that logic "what are you trying to do!?! lose all your backpressure so the car wont move?"

for the record, i cant remember if it was stock that i got the 9hp, i think it was tho

 

I've never heard it put quite so severely, but I've definitely heard lots of "no backpressure = no good" arguments before. It's like guys who think removing/gutting cats doesn't help much either. No, I don't have dyno #'s to prove that one way or another, but it's the same effect.

 

on that note pete, do you know if open headers are no good (other than sound or daily driver) is it damaging? hp or tq increase? btw, i hope you didnt think i was refering to you as an old schooler, i was refering to my cousin who doesnt understand todays engines or speeds. he still believes a old stock 351 windsor will kill a lt1 or even a ls1

 

I don't see running wide open headers hurting as long as you don't run too lean. I know in the case of our '73, it runs way too rich (we really need to jet the carb and things would be a lot better) so for us to open up the headers really benefitted the overall "tune" of the engine, so to speak.

I would "think" that by opening the headers on an LT1 / LS1, between the MAF and the O2 sensors, they should see a significant increase in air flow, and leaner conditions, but I would think the computer could compensate with (enough) more fuel, and things would still be ok?? But I really don't know the full capability of the stock computer/tune/fuel system, to know if everything would be ok or not?? I guarantee you'd get more power running like that, but I can't guarantee it would be "safe" .

 

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damn i prolly would of bidded....but too late.... best place to put cutouts? right after the headers? for open headers?

 

Only need 1. Put it on the I pipe before it goes over the axle.

 

getting true duals will need 2

 

my experience with a cutout. and yes i gained 11rwhp/13rwtq AFTER 3000 rpms. dynos don't show BELOW 3000 rpms unless you can lock the trans into 3rd for an auto.

Now here's results of my exhaust endeavors. This is with 200 n2o. the stock vs cutout was same day.

distance --- stock --- cutout --- cutout colder --- Bassani
60ft ------- 1.987 ---- 2.074 ---- 2.020 ------------1.969
1/8 -------- 7.902 ---- 7.912 ---- 7.990 ----------- 7.739
mph ------- 93.20 ---- 93.97 ---- 92.16 ----------- 98.60
1/4 ------- 12.102 --- 12.080 --- 12.191 ---------- 11.814
mph ------ 117.12 --- 118.06 ---- 118.20 --------- 121.35


NA times

distance --- stock --- cutout --- cutout colder --- Bassani
60ft ------- 2.033 ---- 2.073 ------- 2.031--------- 2.044
330ft ------ 5.788 ---- 5.822 ------- 5.759 -------- 5.723
1/8 -------- 8.808 ---- 8.833 ------- 8.729 -------- 8.656
mph -------- 82.33 --- 82.55 ------- 83.70 -------- 84.27
1000ft ---- 11.404 ---- blank ------ 11.278 ------- 11.196
1/4 ------- 13.606 --- 13.636 ----- 13.449 ------- 13.345
mph ------ 101.66 ---- 101.58 ----- 104.05 ------- 105.15

 

Most cases I have seen, there has always been some sort of gain. The previous owner of my car installed a cutout and gained about .10-.15 in his quarter with the cutout open versus it being closed.

 

If you're keeping your cats, I'd get two and put them at the end of the headers.

 

thats wat im gonna do but with no cats and with true duals