Exhaust Cut-out [Merged 8-9] cut out bypass

[dsmstunna]

Originally posted by rubbersidedown
what does it matter. it'll do pretty much what it advertises. it will open and dump to the atmosphere.

I want to know this because some say u will lose power if you dump at the downpipe. and plus i wanted to know how it sounds.

 

[Eliminat0r]

ok like he only wanted to know if its a good idea and what it will sound like

ok it will sound really loud and everyone will be looknig at you and cops will probably pull you over and give the mirror test to make sure you have a cat (only if you have emission laws in your state)

2. it sounds like a good idea cause its conveinent but if you cant get under your car for the exhaust what are you gonna do bout your intercooler or something else when it breaks or needs cleaning

 

[xcelr8n]

http://www.gopartstrader.com/cgi-bi...t&prev_action=search&session=3f43ef814a1fa174

soory for the lenth of the link, does this actualy work, he lives real close to me, i might be interested if i can get the coin together..
any feedback?

 

[TSi999]

Originally posted by xcelr8n
http://www.gopartstrader.com/cgi-bi...t&prev_action=search&session=3f43ef814a1fa174

soory for the lenth of the link, does this actualy work, he lives real close to me, i might be interested if i can get the coin together..
any feedback?

Ive got a QTEC Quick Time performance electric cutout, its great, havent put it on the TSi yet tho..

 

[xcelr8n]

are those horsepower gains reasonable to assume??
and any idea on difficulty of install.

 

[Streetbeat]

itll just be like drivin your car straight from the downpipe, its gonna be really loud...dont expect 30 hp especially with your mods....id spend the money else where

 

[Travis_GST]

I see your in houston, you must be speaking of wally's wrx....ive talked to him about it too.....he seems to like it

 

[Jon H]

Or..

You could get one of these:

Electronic Downpipe

Anyone have one of these?

 

[Happy]

I had one on my car this summer they sound bad ass at the track loud as #### id pull up to the line and do a burnout and everyone would look!! I noticed a difference with it in to! As well it is a pain my roomat e was goin to get the electric one that a be sweet at a set of lights and click the switch swwwwwwwwwwwwwwwhhhhhhhhhhhhhhhhhhhhhhhh is all ud hear haha!!
As welll i went full 3 inch then the next day my car blew up So now i got a wait for next year!!

 

[swing lo]

people with 4-banger turbo setup's have been know to gain 40 whp with this one http://www.dmhperformance.com

 

[4pistons]

If you're gaining 40 WHEEL horsepower with a cutout your exhaust system sucks! That cutout just dumps exhaust backpressure and anyone with a decent system has very little. If you're running stock exhaust or stock cat then it probably helps.

My homemade 2-1/2" system with a Dynomax Turbo Muffler (3 tube) and test pipe only has about 3 psi of backpressure at WOT in 3rd gear. (Ported 14B, 16 psi, 252 WHP) ANYTHING less than WOT shows less than 1 psi. It is amazing to see that 90% of driving, even aggressively, still isn't even 1 psi.

It is generally accepted that 1 - 2 is excellent 2 - 4 is good and over 6 could really use some improvements.

Just my two cents....

Rick - '91 GSX ...Yes, I have a pressure gauge on my exhaust!

 

[DCJ98GST]

Originally posted by 4pistons

...Yes, I have a pressure gauge on my exhaust!

Can you describe your gauge set up. Did you make the fittings for the tap and is it just a regular boost gauge, or is there a kit you can buy.

Ultimately I would love to get a boost gauge before and after the turbo and log it on AEM EMS in the future.

 

[swing lo]

I didnot say everybody i said some have been know to gain 40 whp and it can happen.

 

[4pistons]

Can you describe your gauge set up

I bought a used Autometer mechanical 0 - 15 psi fuel pressure gauge at a swap meet for $10. I drilled and tapped the downpipe, near the end, for a compression fitting and attached a two foot length of copper tubing. I attached the gauge to the copper tubing with standard plastic tubing and another compression fitting. Total cost - less than $20. I've seen some recent kits out there at around $60 but I put mine together about 3 years ago and didn't see any then so I made mine.

I would love to get a boost gauge before and after the turbo and log it

What do you mean? There is no boost before or after the turbo, only between the compressor and turbine wheels.

some have been know to gain 40 whp

If SOME are gaining 40 WHP with a cutout then their exhaust system sucks! There is no way you will gain that much unless the original system is VERY restrictive to the engine or turbo. If they had a built engine with a 60 trim turbo and bolted on the stock exhaust then maybe. But why would anyone do that? Be careful when reading claims of added horsepower. Find out how they got those numbers.

Rick - '91 GSX

 

[swing lo]

The guy was watched on the dyno with two big eyeballs

 

[stuffy1256]

just got a cut-out! sounds like a freakin huge v-8! i couldnt be happier.... it was only $83 installed at a local exhaust shop. as for gain: i dont know. im still kinda scared to drive it hard cuz of the cops. i got mine before the cat and i sounds really loud. i would completely recommend this to anyone turbo. no rough idle nothing bad about it. go get em

 

[DCJ98GST]

Originally posted by 4pistons
What do you mean? There is no boost before or after the turbo, only between the compressor and turbine wheels.

There is pressure in the exhaust manifold during boost. I would like to log this with the intake manifold pressure and exhaust pressure just after the turbo.

The exhaust manifold pressure is important because it has a significant effect on the VE of the engine. With smaller turbos it is higher per psi of boost. Ideally you would want the same (or more) pressure in the intake manifold as the exhaust manifold for the maximum gain (VE) per boost pressure. This crossover is when you make big power.

Exhaust pressure would be helpful because you could directly calculate the amount of energy (pressure drop) the turbo is requiring per psi.

Does anyone know if multiple pressures can be logged on the AEM EMS? I know you can log at least two pressures.

It would be really nice if AMS or some vender would log these pressures for different turbos.

For example
say
TD04 50 trim w/stage 3 turbine and .63 housing
Boost pressure = 20 psi
Ex Man pres = 18 psi
Exhaut pressure = 1.5 psi
IC drop pressure = 1 psi

This thread is a good read and illustrates how these pressure could be useful.

http://www.dsmtuners.com/forums/showthread.php?s=&threadid=65811&highlight=expansion+ratio

 

[4pistons]

There is pressure in the exhaust manifold during boost

Yes, but the exhaust manifold isn't before or after the turbo. It's between the compressor side and the turbine side. I was confused by what you meant by before and after.

A vendor couldn't tell you the exhaust pressure. That is more a function of your exhaust system, not the turbo. Some of my observations with my pressure gauge bare that out.

you could directly calculate the amount of energy (pressure drop) the turbo is requiring per psi.

The pressure drop across the turbine wheel is more dependant on heat than actual pressure. The more the heat changes from the ex. manifold through the wheel and into the exhaust pipe the faster the turbo will spool.

Having all the different pressures at different areas could be useful info, but maybe it's just too tedious to get and the gains from it not very large. We all know a 16G or 20G can make more power than a 14B or T25 for a street car and that's good enough for most. A serious race team or an engineer might want to wring every last ounce of power out of their setup and deem it worthy. I do like following along with the theories and data though! That was a good thread you linked to.

Rick - '91 GSX

 

[1991gs-t]

Im considering throwing on an electric cutout on my 1g, right on the top of the downpipe....only thing im not too sure about is the sound. I have a feeling it will sound like crap, but if someone could make a video or something and post it, that would be awesome. This way the people here including me can have an idea of what it actually sounds like on a dsm, not a ws6 or a wrx = )

thanks a bunch guys.

 

[markGSX]

I assume it would sound just like an open downpipe (sounds like ass).

 

[1991gs-t]

some peeps say it doesnt sound too bad....thats why i wanted to hear it for myself

 

[Mike1992]

i currently have my exhaust unhooked from my downpipe and when i started it about half an hour ago its sounded like total crap
I suggest no

 

[1991gs-t]

Originally posted by Mike1992
i currently have my exhaust unhooked from my downpipe and when i started it about half an hour ago its sounded like total crap
I suggest no

you're NA...theres probably a much diff sound difference...

 

[Defiant]

Originally posted by 1991gs-t
only thing im not too sure about is the sound.

The people three counties over will be able to tell you how it sounds.

Not a good idea. Stick to the undercar neons.

 

[sherloc123]

im thinking about doing a 3 inch exhaust cut out on my car instead of the 3 inch exhaust. does any one else on here have one or opinions on them? thanks for your time