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Old 02-25-2014, 12:21 AM   #1
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Default 3" exhaust or reroute

I have a T3b turbo, MS3X, LS2 truck coils, and custom intercooler piping on a stock 1.8 engine and I have a little bit of money to spend on the car. I'm trying to decide between changing my crappy 2.5" exhaust with a diy 3" mandrel bent exhaust or a coolant reroute . Right now my cars spools really slow. I'm sure changing the exhaust would improve my spool a good bit. Here is a screenshot of my spool.
3" exhaust or reroute-datalog-pick-boost.jpg

Just wanted some opinions on if I should go with exhaust or reroute. I will be keeping boost at 8 psi for at least another year and am leaning to the exhaust.

Here is a pic of my engine bay as it sits.


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3" exhaust or reroute-cb968c0d-98c7-4149-9b08-1856267f5bd0_zpsd2ad4558.jpg  
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Old 02-25-2014, 08:50 AM   #2
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That's a really really bad datalog.

Maybe it's just me, but i can't see anything from that.

Also, i doubt 2.5" exhaust is slowing your spool that much.
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Old 02-25-2014, 08:58 AM   #3
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Do you have cooling issues? If not i would advise trying to fix that spool issue. I do doubt that the 2.5" downpipe is causing the issue but im sure a 3" would spool faster and make more power anyways. Tune time is likely what you need.
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Old 02-25-2014, 09:49 AM   #4
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Brainy wants your spool data.

Post your spool there for comparison.
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Old 02-25-2014, 11:15 AM   #5
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Is your wastegate adjusted properly?
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Old 02-25-2014, 11:18 AM   #6
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Boost leak?


We just had a thread almost exactly like this a few week ago.
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Old 02-25-2014, 01:05 PM   #7
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Are you tapping your gas pedal foot to a song or something?

Where are you getting your M/EBC wastegate signal from? If it's not from directly below that hideous blue 90* coupler off the throttle body, change that first than come back.
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Old 02-25-2014, 11:17 PM   #8
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Quote:
Is your wastegate adjusted properly?
I'm running a tial 35mm wastegate and don't believe they have any adjustments except changing springs.

Quote:
Where are you getting your M/EBC wastegate signal from? If it's not from directly below that hideous blue 90* coupler off the throttle body, change that first than come back.
Curly, you are right I had that on one of my to do lists and just forgot it, thanks for the reminder. I will also swap out that terrible 90 with a black one.

If these changes don't improve spool I will perform a leak test on the intercooler piping.

Thanks for the suggestions.
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Old 02-26-2014, 02:24 PM   #9
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Make sure you have a bit of preload (spring pressure holding the wastegate flapper closed) with that Tial. If it's cracked open at rest, exhaust is bypassing the turbine.
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Old 02-26-2014, 03:54 PM   #10
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I removed my Tial Bov a couple of months age and need to check and see if the oring got put back on. I will let you guys know if that is my problem. I appreciate all the ideas on what is wrong.
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Old 02-26-2014, 05:25 PM   #11
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BOV and wastegate actuator are two different things. ??
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Old 02-26-2014, 05:42 PM   #12
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I understand the difference in a bov and wastegate. I have a tial bov that was removed and I think I'm missing an oring between the flange and bov that may be causing a boost leak.
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Old 02-26-2014, 08:04 PM   #13
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Also make sure you have the firing ring in your tial gate. Its like a metal o-ring that goes between the flange and the gate, without it you might aswell have the gate open all the time.
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Old 02-27-2014, 01:03 AM   #14
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I was correct there is no oring on the bov. Could this cause a big enough boost leak to account for my late boost. Guess I will hit eBay up for one tomorrow.
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Old 03-02-2014, 09:58 AM   #15
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Quote:
Originally Posted by MrSauce View Post
Also make sure you have the firing ring in your tial gate. Its like a metal o-ring that goes between the flange and the gate, without it you might aswell have the gate open all the time.

^^^^ This!

Early gate opening symptoms. You'd need to have a MAJOR boost leak to spool that slow, and you would hear it for sure.

You definitely don't need 3" exhaust at 8 psi. I'm running 15-17 PSI (depending on weather) and making ~300 whp through 2.5" exhaust and see no reason to go bigger at this power level. Hell I made 235 whp on 12 psi through the STOCK exhaust.
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Old 03-02-2014, 02:34 PM   #16
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Thanks for the reply. I didn't think a boost leak would slow my spool this much. I will check the wastegate but I'm pretty sure the firing ring is in there. It never hurts to double check.
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Old 03-05-2014, 12:33 PM   #17
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Installed new bov flange oring and took the car for a drive. The datalog shows better spool, but after looking at the old logs they show I was only at partial throtlle (50%). Here is a pic of the datalog. This is a 3rd gear pull.


Do you guys think that this is reasonable spool for my setup. Let me know if you want me to load any other information.
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3" exhaust or reroute-3rd-gear-pull.jpg   3" exhaust or reroute-3rdgearpull_zpsa40c7244.jpg  
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Old 03-05-2014, 12:45 PM   #18
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That looks much more reasonable.

Why part throttle? Were you really part throttle or do you need to calibrate your TPS? Being part throttle hurts spool (obviously).
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Old 03-05-2014, 12:56 PM   #19
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Hornetball you may be correct that my tps calibration was incorrect and it was actually full throttle. I did have my tps wired incorrectly at one point but I'm not sure if I fixed it before or after the previous spool data.

How much spool could I possible gain from changing from a crush bent exhaust to a 3" mandrell bent exhaust?
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Old 03-05-2014, 01:11 PM   #20
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Why do you keep wanting to spend money on your car when it's not needed?
Fix the tune. It's free, and easy.
Find the problem. Fix the problem.
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