Thanks for your suggestion, I'll try this.

 

Was it 15 deg WARMER the day you did the runs with the muffler delete installed? Intercooled turbo cars are much more sensative to temperature changes than NA cars.

Keith

 

I'm not going to get into a pissing contest with you. Besides, why are you pissed off? I'm the one who's car is down 17% in hp!

You might not be. Use a real dyno!

You must not have much experience using the G-Tech accelerometer. I did no less than 5 runs two days ago and they were all extremely close (1%). Do you really believe using a butt-dyno will yield more accurate measurements?

That's because I've found them to be very inconsistent. Unlike a dragstrip or a dyno, the latter offers proven correction factors for environmental conditions. Regarding butt dyno, you're preaching to the choir. Its not accurate at all, nor did I ever claim it was.

I'm not flaming them - only asking for assistance from some of the folks here. I've already been told by someone that what I'm experiencing is expected. Given this, I'm somewhat puzzled why Buschar didn't mention it to me in my correspondences leading to the purchase of the pipe.

And I'm trying to offer you assistance. I did NOT lose any boost with my muffler delete pipe. Another local guy has one and he didn't lose any boost either. What I did lose boost with was the test pipe, but I compensated with an MBC.

Had I known that I'd have to install a MBC in order to make stock hp with the pipe I would have passed on the purchase. My vehicle is basically stock and that's the way I want to keep it as to not void my extended warranty.

Agreed, but are you using a boost controller to prove loss or just the GTech? I want to see how much actual boost you are running before and after installation, please.


To asnswer some of your questions: No, not the same stretch of road, however both of them were basically both level and at the same elevation. No, the car was not at exactly the same operating temperature. Yes, the outside temp did change by 15 degrees. No, the electric fan was not on for either test (not that it would have mattered). As my post indicated, I used the G-Tech to gauge performance since has proven to be quite consistent.

Consistent meaning identical runs in identical circumstances. If its consistent in a 15 degree variation and at different operating temperatures, throw it out the window! I've seen several dyno runs where these cars make very inconsistent power at different operating temperatures.


Sounds like a very scientific test. Was it run on the same day? Was the temp the same? Etc...

I thought you didn't want to get in a pissing contest? The WRX and 350Z explanations were for illustration. You don't need identical conditions outside when the two cars being compared are exposed to identical conditions to one another. Point for the WRX was that I pulled more convincingly starting at the same speed that we both noticed the difference. Point for the 350Z was that we were close when I was stock. $500 invested in my car, I absolutely blow his doors off.

Did you read my post? If they knew that the pipe would cause a loss in boost and result in much lower performance than stock, they should have told me. If they didn't know this, then you draw your own conclusions.


I did read your post, because I am trying to help you. I'm saying that I did NOT lose boost, and that everybody else that I know of that is using it who tested it on a dyno gained power.

Of course it isn't installed wrong. But don't expect to use an accelerometer as a yardstick and expect us to accept it as undeniable truth, especially when we have track times and dyno numbers that tell us exactly the opposite of what you are saying. No hard feelings. I hope you get your issues resolved. FWIW, nobody has reported more than a 1psi loss with an axle-back, and several people report no losses. Tell us your actual PSI or KPa level of boost before and after so we can have more understanding of the situation.

 

I wish I had noted the boost levels when I ran the test yesterday. To tell you the truth, I don't even know if the boost was lower. I've been told that this was the probable cause and I've accepted it as true. All I know is that the car didn't pull as well and this is what I measured with the accelerometer.

Consistent meaning two days ago when I measured 223hp, I did 4 other runs and they were all very close to one another. I agree that the comparison wasn't 100% apples to apples, but it certainly wasn't apples to oranges. The second test was also done with a 160lb weight advantage since my friend wasn't in the car.

Thanks, and sorry for my harsh response. I'm just not real happy about the situation. I will put the stock muffler back on and rerun my tests. If the power comes back then I know what I'll have to do. Thanks, Mike.

 

#1- Go out in the car right now and check your boost at a WOT run.

The 160 lbs of the friend.. You have to give the Gtech a curb weight with passengers included, correct?

Here's my plan for most scientific possible with an accelerometer. Fire up the car and let it warm up for about 2 miles, then drive it aggressively for about one minute. Right after that, perform your Gtech test with only you in the car. Go home, throw on some mechanix gloves (or something that will stop you from getting burned) and ASAP swap to the stocker. Do the run again and see what happens. I think you'll really like the BR pipe once you get everything ironed out! The weight savings alone is great, but I love the top end flow, ESPECIALLY after the SAFC. Just with those two parts, the car transformed into a monster from 4500-redline and beyond.

Edit: I was harsh too, no sweat! I'd think with that wicked 900RR you have in your sig, the Evo would feel like a total dog. Sweet bike.

 

We arent talking about big big gains here fact is its just noticable and there are very qualified people who will swear that the butt dyno is insensitive to such a small gain the effect was like an uppipe on a wrx better response and less choked up top. this little gtech aint going to do much. Hell run to run on a dyno could be worth the same gain or drop

 

I can verify that I lost boost when my delete pipe was installed. Went from 19 max tapering to 16-17...to 18 max tapering to 16-16.5

 

OK, we have several people saying basically the same thing - now can any of the smart tuner folks explain why?

Sounds like it is pointless, except for the weight saving, to install a low restriction muffler unless you are going to combine it with other mods such as a BC or reflash to compensate for the boost reduction.

 

Reflash won't really help bring the boost back up ans sustaining it at 19. I had my car Dynoflashed this past Sat. Read my thread and you'll find some info https://www.evolutionm.net/forums/sh...threadid=46561

 

The car runs a peak maximum boost from the factory will all things stock of 19 psi, this will fall off over 4,500 rpm to 16 psi or there about. We found that even with extensive mods (stage 2) on our car and the stock boost controller hooked up that the boost stayed the same, 19 peak 16 or so when it fell off.

I am not sure why your boost fell off, you weren't warned about it from us because we have never noticed it. The car even with 1 psi loss in boost pressure should still have more HP with the muffler delete pipe than it did with the stock muffler and a pound more boost.

Try running the tank completely out of fuel, put a full tank of the highest octane you can in the car. Then go run the car with the meter (which I would have NO faith in) and then put the stock muffler back on and see what happens. Octane plays a big role int he power making of these engine.

David Buschur
www.buschurracing.com

 

Thanks for your feedback, David. Although I normally run 92 octane, I was running 94 octane for both of these tests (same tank of gas). As you and others have suggested, I'll retun the tests in the next day or so and report back. Thanks, Mike.

 

mikec-

Set your TurboXS "standard" mbc at 19psi. Strap on a DP (2.5"-3.0"; your pick) and proceed to make 280awhp with the assistance of the "Stage Rev" DynoFlash.
You're $500 dollars away (assuming you already have a boost gauge).

4-BNGR

 

I too was running 94 octane at the time of my reflash and boost still dropped off. I'll try putting the stock mufler back on and see what results I get.

Do you recommend resetting the ECU after I put the stock muffler back on?

 

4-BNGR, are you psychic? The only reason I can't rerun the tests today is because my ECU is on the way back to me after having the "Stage Rev" DynoFlash done on it.

Is there a specific post or how-to here on evolutionm that describes how to connect the TurboXS MBC?

Thanks, Mike.

 

After reading everything posted here, the only question I have is if a cat back exhaust is really worth it. Unfortunate for me I have already ordered a WORKS rally exhale pipe. Though I have to say I discuss a lot of the things that I read here and the guy I spoke to assured me that I will see a 10-15HP gain with the pipe installed. I have a series of 3 mods I am in the process of adding, the Exhale pipe being the first. This mod is being followed with a Breath throttle body and a WORKS Brain Flash w/boost enhansment. I would recommend that people take a look at their web site. I had noticed boost drop off at higher RPM's also and they showed me how this happens. I will let you know how the new pipe works after it is installed later this week.
I hope some of the info on their site helps www.worksrally.com