How many of u Dump your wastegate into the atmosphere, and what do u use to quiet it down. we just did mine tonight, and this **** is loud as hell when it opens up. i know it supposed to give more power but i dont know if its worth the extra 15 to 20hp when the car sounds like this. ill be going to the dyno again on friday evening to see exactly what change this makes. BUT PLease if there are any susgestions, im open for them.

 

only way to quiet it down is to stick it into the exhaust. and there are no power gains from venting it to atmosphere. it's just easier to have the piping that way. i agree it's pretty freakin loud though. i try to not boost very high if i'm anywhere that the noise might draw attention

 

It's loud as hell and I love it! BRRRRRAAAAAAAAAAAAAAAAAAAAAAAA!

Scares the **** out of other drivers. However it does attract huge amounts of police interest....

Let us know what the dyno shows you lose by putting it back in the exhaust (if anything)

B

 

Has anybody tried using a small muffler on the dump tube?

I'm not sure about that. Plumbing it back into the main exhaust pipe increases the backpressure on the turbo and in the wastegate pipe.

Granted, if the WG is able to control boost (meaning it's not 100% open) I don't see how anyhing can be gained by reducing the backpressure behind the gate since doing so would bleed off more pressure than necessary and therefore require the gate to be closed more to compensate.

However, reducing the backpressure behind the turbo may improve top end if the exhaust system is a limiting factor.

 

A guy that used to run a Dynojet shop down here suggested to extend the dump tube back and add a small muffler (maybe from a motorcycle?) to quiet it down. Not sure how feasible it is given the space constraints under a FD chassis...

 

Dump it! It helps on the top end and high psi numbers.

 

dumping it is like adding an extra inch onto your entire system... im gonna dump mine, cant wait for the noise

 

if your worried about the noise put a long tube on the wastegate, a few feet, enough to get under the car and put a small muffler on there. u minght have to replace it on a regualr basis but i am sure it would stil sound pretty mean.

 

Well..... Here are my results from tonight.

404 RWHP & 345 Torque @ 18.5 PSI on PUMP Gas 93 Octane

i figure we got a 26HP increase from dumping the wastegate and going from an HKS Foam Filter to a K&N

Air Fuel is linear at like 11.4 to 11.9 the highest.

im going to see if i can get my scanner working so i can post the sheet.

 

Well..... Here are my results from tonight.

404 RWHP & 345 Torque @ 18.5 PSI on PUMP Gas 93 Octane

i figure we got a 26HP increase from dumping the wastegate and going from an HKS Foam Filter to a K&N

Air Fuel is linear at like 11.4 to 11.9 the highest.

im going to see if i can get my scanner working so i can post the sheet.

 

what kind of turbo are you running? torque looks pretty high for the hp number. i'd also bring the a/f down just a tad. anything close to 12:1 running that kinda boost is really cuttin it close. fwiw, my t78 put down 439hp and 333ft lbs on 16psi with the a/f dipping into the 9's

 

Woooh! You're a/f ratio dipping into 9's! That's way too rich! And if they dip in it's 11.4 that's a bit too lean. There are a couple of things you guys need to consider when tunning.

First when tunning you are in enviroment that the air is not coming as fast as if the car where actually on the road so you will always like it to be a little rich. I recommend that a mid 10 a/f would be good.

Second many people are running great fuel set ups, but shitty *** timing. You may want to make sure that your cars timing is not retarded, though this is okay for a drag car this will blow street cars. I suggest you keep your timing between 30-35 while idling, and between 15-20 when boosting really high.

Hope this was helpful,
Alex

 

I was think of this Small muffler from a (dont laugh to hard) lawn mower. I remember that last time I was in lowes that they had a decent size muffler in there. about 3 inch diameter by 6 inches long.

Just a thought

 

sounds a little risky if ya ask me. when i'm up top, i have 14* total advance with 8* split and 9.5-10 a/f. it makes good power and i don't think it'll be too lean anytime soon

 

according to the XS technicians, they have seen a 15-20rwhp loss on the dyno from routing the wastegate back into the downpipe. This is from increased backpressure....rob, what turbo are you running? Just leave it open since it's not loud until you get on it anyways

 

Actually that's not too bad, you're running extremely rich to compensate for how retarded your timing is running. Your car will be just fine, still I just to change your timing and bump up your a/f a little, it'll save you more gas if that makes a difference. Also your plugs will last longer, injectors will last longer before they need cleaning, and so will your fuel filter. It's just an idea.

Alex

 

Car Has a TS04 Turbo with a P wheel. Im running a mild streetport with 850 primaries and 1600 secondaries. As for timming im at 13* at 19 PSI with a 10* split. im running NGK Irridium Plugs B10 which are real cold plugs. As for the enviorment, i live in Florida so the temps are pretty steady here. I do see what u say though about the air fuel being kind of close. but consider this, Ive made 62 Dyno runs over a period of 3 visits and car is running harder than ever. For me 404 feels like the perfect recipe to put a woopin on all these Evos, Subarus, Civics, ETC that hang around here. LOL . As for the Torque Curve, Keep in mind that this was a 4th Gear Pull.

 

the dyno should always be used with a 4th gear pull.

and ive heard that we shouldent run over about 12degrees advance at like 15psi with these big turbos.

I know in the subaru world the best way to tune is to dial in the afr, then get the boost as high as you want to run, then increase timing until you only see about a 5hp gain per degree, back it off one and then your done. (sounds simple dont it)

 

When I was on the dyno last week all the tuning was being done in 2nd gear. Is that something I should be concerned with?

 

By the way right now my wg is dumped but i was planning on putting it through the exhaust. If the sound is tolerable I may just leave it as is.

 

not entirely, but most tuning is usually done in 4th gear. 2nd gear doesn't usually put a hard enough load on a car to get accurate a/f readings. and you also have to take into exception that your a/f is going to go up slightly on the street, increasing chances of detonation

 

Yeah, that and his boost is gonna be higher on the street when he reaches 4th and 5th gear :/

May i ask which shop was dynoing in 2nd gear, In the subaru world thats a big no no. (it also affects hp numbers)

 

When the car is finished I had planned on doing some additional tuning on the street in order to get the most accurate results. dyno's are great but they just can't mimic real driving.

 

I should state that it wasn't only in 2nd gear. We drove through 4th and 5th as well. We were not able to finish tuning due to a bad coil and fouled plugs. The shop is in Red Deer Albera and I can;t say enough good things about the tuner. Sorry I should have said the majority of tuning was done in 2nd gear, but we were also having to do everything from scatch. We were tuning up to 5k rpm with no boost just to get the car drivable so the engine could be broken in.

 

In the subaru world this in the subaru world that. In every car world you want to dyno in the gear that is closest to a 1:1 ratio wether that is 2nd,3rd,4th, or 5th.