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2.5" or 3" for Road Race

So I went with 3" mild steel exhaust. ATP Ultimate Wastegate, Borla round XR1 3" muffler, and side exit before the right rear wheel. I ported the wastegate hole what I thought was a bunch. Apparently I did not port the wastegate enough or use enough pipe/bends as I had a massive boost increase after 5k RPM, pegging the boost gauge at 20+ PSI. Target boost is 12-15.

Ben suggested running full length over the axle. I am going to port further and try over the axle.

It is much louder than before, but wasn't ear bleeding. Still quieter than the Miatas.
 
culberro said:
What diameter did you open up the WG hole to?
Click to expand...

I dont remember. I could have gone a lot more than I did, but I got lazy because my compressor sucks. Certainly not as much as you recommended.

jCGUWczl.jpg
 
rb92673 said:
I dont remember. I could have gone a lot more than I did, but I got lazy because my compressor sucks. Certainly not as much as you recommended.
Click to expand...

Go grab an electric die grinder from HF and one of their router speed controllers. Never wait for a compressor again.
 
rb92673 said:
It is much louder than before, but wasn't ear bleeding. Still quieter than the Miatas.
Click to expand...

We got done for sound again. Going to need a new strategy. 8(

Congrats on turning many laps & mostly not being parked with the hood up. You seemed to be mostly grinning. 8)
 
DrZiplok said:
We got done for sound again. Going to need a new strategy. 8(

Congrats on turning many laps & mostly not being parked with the hood up. You seemed to be mostly grinning. 8)
Click to expand...

Maybe you should add a turbo to reduce the sound?

We were very happy with our results. We worked on the basics of trying to stay out of trouble and efficient driver changes. We had more black flags than I wanted, but the car didn't have any major issues. Sorry yours decided it didn't like turning.
 
culberro said:
What diameter did you open up the WG hole to?
Click to expand...

Bought a new Garrett T3/T4 and 3" Ultimate V-Band. It felt wrong to immediately start grinding on a brand new turbo. Original wastegate hole was about 25mm. Opened up to almost 28mm at widest and 27mm at narrowest point. Did not take off as much where the flapper swivels. Also tried to smooth out the transitions.

<blockquote class="imgur-embed-pub" lang="en" data-id="a/U1pnoMi" ><a href="//imgur.com/a/U1pnoMi">Turbo porting</a></blockquote><script async src="//s.imgur.com/min/embed.js" charset="utf-8"></script>

Hopefully this works to stop the boost creep.
 
That should be a large improvement. Just increasing the diameter from 25mm to 27mm is almost a 20% in area alone!
The ATP/garrett 0.63 housing needs a bit more work vs how it's supplied, that's for sure.

Al (megulon-7) had the same issue with boost creep on his garrett with the 0.63 turbine housing.
ATP did some porting and put a fat groove from the t3 flange and then rounded/tapered into the WG hole. I did something very similar, as did Harlard.
 
culberro said:
ATP did some porting and put a fat groove from the t3 flange and then rounded/tapered into the WG hole. I did something very similar, as did Harlard.
Click to expand...

Got any pictures? I asked ATP if they could port before I ordered and they said no.

I think I am going to go at it again with the grinder. Having to short shift during a race is annoying as F. We are going to Willow Springs next and we need more speed.
 
I think I have the 0.63 housing somewhere still. I see if I can find it and post some pics.

One issue it had, the WG flapper pivot started to wear and the flapper dropped slightly. This made it so the flapper wasn't covering the WG hole completely and it was slow to bewst. Soooo take that into account whenever I post the pics.
 
culberro said:
I think I have the 0.63 housing somewhere still. I see if I can find it and post some pics.

One issue it had, the WG flapper pivot started to wear and the flapper dropped slightly. This made it so the flapper wasn't covering the WG hole completely and it was slow to bewst. Soooo take that into account whenever I post the pics.
Click to expand...

Thanks. Much appreciated.
 
Just to follow up on this.

Ported a new Garrett T04E to about 27-28mm and went 3" all the way to rear bumper with a round Borla XR1. Wastegate actuator was set at .8 bar. Raced two days at Willow Springs and had absolutely no boost creep. Super happy with result.

FWIW, I saw 117 MPH via GPS at the end of the main straight at big Willow.

Thanks for all the suggestions. They worked. Maybe its time to go to 1 bar. :)
 
That's great to hear! I realized that my post with the pictures got removed when the forum got reset... so here ya go again.
Don't open up the WG hole this far, it will definitely limit your boost creep... and maximize the turbo response time!

52013562871_8672f60574_w.jpg


52013810799_af4bccd591_w.jpg


52014081370_652f276172_w.jpg
 
culberro said:
That's great to hear! I realized that my post with the pictures got removed when the forum got reset... so here ya go again.
Don't open up the WG hole this far, it will definitely limit your boost creep... and maximize the turbo response time!
Click to expand...

Thanks.

Does the porting need to be more as you add more boost? It was rock solid at .8 bar, but I am going to try a 1 bar spring for the next race. Before porting on my other T04E and stock exhaust I would see boost creep to about 1 bar.
 
rb92673 said:
Thanks.

Does the porting need to be more as you add more boost? It was rock solid at .8 bar, but I am going to try a 1 bar spring for the next race. Before porting on my other T04E and stock exhaust I would see boost creep to about 1 bar.
Click to expand...

Usually less porting (or less WG) is what you need at higher boost levels.
The 27-28mm that you have is perfect. The 30.5mm that I ended up with is not what you want since the WG flapper wasn't sealing all the way around.
 
culberro said:
Usually less porting (or less WG) is what you need at higher boost levels.
The 27-28mm that you have is perfect. The 30.5mm that I ended up with is not what you want since the WG flapper wasn't sealing all the way around.
Click to expand...

Thanks. I feel better now.
 
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