60mm ebay wastegate as a cut out 65+ whp gain

[Boostdriven]

Just wanted to share with you guys a cheap mod I did to my car a year or so ago that opened up 65+ whp on the car.

I'm know this has been done before with exhaust cut-outs but I wanted to do something different due to lack of room and simplicity of a wastegate.

I've been to a dyno with my car few times now and fortunately its been a little more HP each time. The last time I went to a dyno before this mod, car made 517 whp at 32 psi. One thing that I noticed that even though I had all the supporting mods my engine was dropping power past 7600 rpms.

After doing some research I figured my 3" turbo back exhaust just wasn't cutting it so instead of spending hours and hours rebuilding my exhaust to 3.5" I bought an eBay 60mm wastegate, ($125 shipped) it was 60mm in and 60mm out. I ended up welding it on to my down pipe about 14-16 inches passed my turbo right under the oil filter housing. It came with few different springs so I ended up using the one that was like 13 pounds. I ran a boost line to it from my compressor cover.

After all said and done I took the car out for a drive and right away I could feel the increased power at higher rpms. I didn't change anything else on the car with an exception of some minor fuel adjustments to get air/fuel ration in check.

About a month later I took the car back to the same dyno in Portland OR and to my surprise car made 577 whp on the first pull at 31 psi. With some minor tweaking the second pull made 580 still at 31 psi. I had them spin the engine to 8000 rpms and the HP never dropped, air/fuel ratios were right around 11.1-11.3, yes I like it safe I think I have that dyno sheep posted in my profile.

I was so surprised and excited at the same time that I told those guys there was no reason to do a third pull, I didn't think there was much I could do to a tune to get much more HP out of it except maybe to raise boost but I didn't want to mess with my timing. This was all done on 92 pump gas and water/meth with 19* of timing by red line with 6 blade HX40 BEP .70 housing.

Looking at my few previous dyno sheets my 3" exhaust was becoming a restriction at about 27 psi and about 480+ whp.

Just some information form personal experience for those who are running similar setup and HP.

 

[96mitsugsx]

Do you have pics?

 

[Boostdriven]

I don't but I will take a few and try to post them later tonight.

 

[rr06rs]

Here's ATP's. Had one on my gti. 60mm just is a little small to me when talking exhaust. VES-ASSEMBLY - out of stock again until unknown date due to production delays : atpturbo.com not sure if they're still making it..

 

[Boomdeeze]

Thats a good idea, a popular one is th QTP electric cutout: QTP » Electric Exhaust Cutouts

That is the one I plan to run but this is a cheaper alternative for sure.

 

[ZenkaiRacerDsM]

I want to do the same thing. I have a 50mm wastegate collecting dust and I already have a 3in cutout welded into my downpipe. I just need someone to weld something up so the wastegate can be put in place of the cutout cap.

 

[Boostdriven]

It wasn't just a reason in price why I went with a wastegate but because electronic cut-outs are electronic there is a lot of heat right after the turbo and a wastegate is designed just for that, plus it was a simple fix with no wires and switches just one boost line. As long as the diaphragm holds up in that wastegate it will outlast any electronic cut-outs out there, and if it doesn't I'll replace it with a tial one since the wastegate looks like a copy of tial.

 

[ZenkaiRacerDsM]

Yeah I agree. I already have a new electric cutout that I don't want to install anymore. Would much rather install the wastegate.

 

[Boostdriven]

Yeah I agree. I already have a new electric cutout that I don't want to install anymore. Would much rather install the wastegate.

Don't let me stray you down a wrong path

 

[Alex7747]

Wow, this is so simple but i would have never thought about it. Could this be done with a stock exhaust and still see some good improvements or would you still need a good sized exhaust to start?

If i wanted a stock exhaust (because i hate loud exhausts haha) could i do this for when i want to step on it and make the power?

 

[ZenkaiRacerDsM]

Haha I've wanted to do the wastegate thing before I saw this thread, just never got around to it.

Currently my exhaust is fairly quiet and my car just sounds really tame. Until I hit boost and the wastegate opens. Will much more shocking when the cutout does the same thing heh.

Whenever I have to have someone else do some work for my car I procrastinate forever. I mean I procrastinate enough when I do things myself, let alone when I have to take it to someone else.

Wow, this is so simple but i would have never thought about it. Could this be done with a stock exhaust and still see some good improvements or would you still need a good sized exhaust to start?

If i wanted a stock exhaust (because i hate loud exhausts haha) could i do this for when i want to step on it and make the power?

You can definitely do it with a stock exhaust. You would see even more gains since your exhaust is an even bigger restriction.

 

[Boostdriven]

Wow, this is so simple but i would have never thought about it. Could this be done with a stock exhaust and still see some good improvements or would you still need a good sized exhaust to start?

If i wanted a stock exhaust (because i hate loud exhausts haha) could i do this for when i want to step on it and make the power?

What you could do is still run nice 3" exhaust all the way down to the back of the car and then put a stock muffler on there for it to be quiet. If your car is making 350-400 one 60mm might not be enough because that stock muffler will cut off a lot of the exhaust flow, and if you had to use two 60mm wastegate to compensate for the stock muffler then I would just buy a nice 3" electronic cutout. It will cost you about the same but you won't have to do the work twice.

If you were to run a completely stock exhaust from the turbo I would then at least put a nice 3" pipe to your cutout, but if your going to run 2-3 feet of 3" pipe I would run it all the way to the cat.

I'm not sure but I think I seen somewhere cutouts that were mechanical, like old school cable controlled. If you could get the body and the valve itself you could fab up a wastegate actuator from like a t25 or 14g to run the valve, it would then be boost activated.

 

[dsmcurse]

"60mm just seems small for exhaust"
That doesnt really make sense to me because its as big as the throttle body that feeds our engines. 60mm is close to 2.5".so to magically get a two and a half inch hole to appear in a three inch pipe is pretty dank sauce in my book.

Wastegate vs cutout....hmmm.... Id take the 60mm WG any day over the electric cut out and ill tell you why. The wastegate trick is pure automatic takes care of its self, boost activated, mechanical reliability, no wires to get burnt and crisspy, no toggle switch to install inside car, no "opps i forgot to flick my cut out button", wastegate will survive the hotness and outlast a cut out.
Now grant it, the actuall cut out will open up a bit further, BUT, not by much. The pros of using a WG easily out way the cons. A 60mm hole that magically appears after your turbo will do wonders for back pressure drop.

And while were on the topic of back-pressure (E-Map) id strongly suggest to any one running a cut out to install a boost gauge into your exhaust mannifold or turbo header. A diesel boost gauge (only shows boost not vacume) works awsome here. You tap a ferral fitting into the manni befor the turbo, come off the manni at least three feet with the copper/metal bendable/flexable kinda hose-tubing, after that the hotness has died down enough to then transfer into traditional nylon boost gauge hose to run into the cabin of the car and hook up at the guage.
My and boostdriven both have ours set up to where when the copper hot hose transfers into the standard nylon hose, we have a Tee right there and the Tee feeds a map sensor that logs in link.

Its very interesting to kill all the gauges in link except rpm, map and e-map. To see boost line lapped over a backpressure line is good info to see how efficient your engine/set-up trully is.

Good info in here

 

[Boostdriven]

Here are few pictures of my wastegate (cutout)

 

[ZenkaiRacerDsM]

Nice setup. I take it your car never sees bad weather with how clean that wrap is heh.

 

[Alex7747]

What you could do is still run nice 3" exhaust all the way down to the back of the car and then put a stock muffler on there for it to be quiet. If your car is making 350-400 one 60mm might not be enough because that stock muffler will cut off a lot of the exhaust flow, and if you had to use two 60mm wastegate to compensate for the stock muffler then I would just buy a nice 3" electronic cutout. It will cost you about the same but you won't have to do the work twice.

If you were to run a completely stock exhaust from the turbo I would then at least put a nice 3" pipe to your cutout, but if your going to run 2-3 feet of 3" pipe I would run it all the way to the cat.

I'm not sure but I think I seen somewhere cutouts that were mechanical, like old school cable controlled. If you could get the body and the valve itself you could fab up a wastegate actuator from like a t25 or 14g to run the valve, it would then be boost activated.

Some very nice ideas man ill have to try the t25,14b custom valve or see if i could manage it haha but ill more then likely make a full 3" turbo back exhaust and then maybe a stock muffler and two wastegates or the electric cut out.

Thanks for all the ideas man

 

[2gSpyder4g64]

wow thats really clever ive never think of that.... , could you post more pics, and maybe a clip of it working?

 

[Boostdriven]

Nice setup. I take it your car never sees bad weather with how clean that wrap is heh.

The wrap is actually new, I just replaced it when I put a machined garrett housing on my HX40

 

[rr06rs]

"60mm just seems small for exhaust"
That doesnt really make sense to me because its as big as the throttle body that feeds our engines. 60mm is close to 2.5".so to magically get a two and a half inch hole to appear in a three inch pipe is pretty dank sauce in my book.

Wastegate vs cutout....hmmm.... Id take the 60mm WG any day over the electric cut out and ill tell you why. The wastegate trick is pure automatic takes care of its self, boost activated, mechanical reliability, no wires to get burnt and crisspy, no toggle switch to install inside car, no "opps i forgot to flick my cut out button", wastegate will survive the hotness and outlast a cut out.
Now grant it, the actuall cut out will open up a bit further, BUT, not by much. The pros of using a WG easily out way the cons. A 60mm hole that magically appears after your turbo will do wonders for back pressure drop.

And while were on the topic of back-pressure (E-Map) id strongly suggest to any one running a cut out to install a boost gauge into your exhaust mannifold or turbo header. A diesel boost gauge (only shows boost not vacume) works awsome here. You tap a ferral fitting into the manni befor the turbo, come off the manni at least three feet with the copper/metal bendable/flexable kinda hose-tubing, after that the hotness has died down enough to then transfer into traditional nylon boost gauge hose to run into the cabin of the car and hook up at the guage.
My and boostdriven both have ours set up to where when the copper hot hose transfers into the standard nylon hose, we have a Tee right there and the Tee feeds a map sensor that logs in link.

Its very interesting to kill all the gauges in link except rpm, map and e-map. To see boost line lapped over a backpressure line is good info to see how efficient your engine/set-up trully is.

Good info in here

I suppose I should rephrase that. I would rather use something like the atp one that's a full 3" while still not having to worry about failing electronics, than something that's 2.5". None the less, its still a great idea!

 

[4gfun]

This is excellent! Thank you.

Is there any way that anyone can think of to make this work without welding? I just don't have the welding skills but already had a 2.5 inch cutout welded pre cat.

 

[Boostdriven]

This is excellent! Thank you.

Is there any way that anyone can think of to make this work without welding? I just don't have the welding skills but already had a 2.5 inch cutout welded pre cat.

I don't think you can get away without doing some welding. The best way would be cut the flange off your cutout and fit the waste to your pipe and then weld the wastegate ring to the pipe. You might have to extend that pipe or shorten it depending what space you have to work with.
You other option would be to get another flange to match your existing flange and a 2.5" piece of pipe. Bolt your new flange to the existing one, you will use that piece if pipe space your wastegate from the flanges. It don't have to be long 1.5-2.5 inches or whatever it would take to fit the wastegate in the space that you have.

I don't know what your working with but I'm sure u might have to cut some angles on that pipe to set everything up right. Makes sure your cuts are clean and straight, it makes it much easier to weld later. Once that's done position everything like it would sit welded and mark your new flange against the pipe and pipe against the wastegate. Make sure you make few marks that you would be able to line up later. Take everything off and take it to someone who can weld that together for you. Whoever welds it for you will have to line everything to your marks and weld it. Make sure when he welds wastegate ring to the pipe that the wastegate is clamped to the ring, otherwise your ring might warp and you won't get a good seal later. After you get that done then all you have to do is bolt it up to your exhaust and run boost hose to your bottom port on the wastegate. Make sure the spring in the wastegate is like half the boost pressure your running.

 

[YoYo_4G63]

Amazing idea! Do you have external wastegate as well? I bet a full 3" exhaust, vented wastegate + that "cutout" idea should sound equal to an open downpipe right?

 

[Boostdriven]

Amazing idea! Do you have external wastegate as well? I bet a full 3" exhaust, vented wastegate + that "cutout" idea should sound equal to an open downpipe right?

Yes 50mm external wastegate. I don't think its as loud as an open down pipe but once everything opens up it gets loud. One thing I noticed after running few different external wastegates, the bigger the wastegate the quieter it is.

 

[Boomdeeze]

The reason I choose the electric cutout over a setup like this is, I would like to be able to get on it without the sounds of a open dump tube. I have my WG recirculated to a true 3" exhaust and plan to run it to a dual tip performance muffler with no cat. The dual tip should quiet it down and give it a semi stock look while the electric cutout will be more for track. So not only the electric cutout being larger but being able to keep my car quiet when I want it to be quiet and let her scream when it matters. This WG idea is a great idea but the cons you listed fof the EC really don't matter as your wires shouldn't get burnt as long as your not running it along the exhaust. And if you "forget" to open your cutout, then your probably not worried about if the other car can keep up

 

[habitatguy187]

And while were on the topic of back-pressure (E-Map) id strongly suggest to any one running a cut out to install a boost gauge into your exhaust mannifold or turbo header.

To see boost line lapped over a backpressure line is good info to see how efficient your engine/set-up trully is.

Is your exhaust 3" all the way as well as the cutout? I've always been curious to know where 3" exhaust actually becomes a restriction but never seen anyone actually test it.