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Post by RacingJake on Jul 19, 2020 12:00:43 GMT -5
I'm getting compressor surge when backing off the throttle like WOT to 3/4. Boost is 25 psi with T3T4 50 trim turbo and running a Stinger BOV at the throttle body and a second Ebay dual port BOV just past the turbo. Thinking I need to step up to a bigger BOV setup.
Heck I can get compressor surge at half throttle once rpm is over 4K and I back off.
Jake 87 TC
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Post by Stinger on Jul 19, 2020 13:41:38 GMT -5
If two BOV's isn't curing it then the problem is not that you need a larger one considering most people don't have the problem with a single BOV. 50 Trim turbos are also very resistant to surge because the MAP is so forgiving at the surge line. So I'd suspect whatever it is, it's not surge.
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Post by RacingJake on Jul 19, 2020 16:15:10 GMT -5
Interesting ? I was thinking they are too small and with the boost being so high that they don't respond fast enough.
I did soften the spring pressure so much that I could hear it venting all the way to 22 psi, gotta love this turbo.
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Post by Stinger on Jul 19, 2020 19:14:25 GMT -5
Boost pressure doesn't have anything to do with the ability to vent, at least not in the way you're thinking. Technically the higher the boost the more air you can "dump" out of a BOV as the pressure differential between boost pressure and atmosphere is greater the higher the boost.
Please explain "I did soften the spring pressure so much that I could hear it venting all the way to 22 psi" as I'm not sure what you mean since BOV's aren't supposed to vent until the throttle is released.
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Post by RacingJake on Jul 20, 2020 17:19:11 GMT -5
Thanks Shannon, It's a adjustable BOV that increases or decreases spring pressure with a set screw, most start higher but I started at a lower spring pressure and increased spring pressure one turn at a time after a few test runs. At least I know it's working.
I've been wanting to put some 110 fuel in her and turn the boost up to 30 but I don't think the stock rods would like it ?
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Post by Stinger on Jul 20, 2020 19:55:31 GMT -5
What fuel are you using currently?
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Post by RacingJake on Jul 21, 2020 18:09:58 GMT -5
I run 93 pump in the TC and VP110 in my drag bike with nitrous.
I've never done a compression test and never had any pinging either with your Pimp ECU. After installing your 3" exhaust system I did another auto tune and it just gets better. Been thinking of adding a 50 shot of nitrous from 3 to 4 K to get it to spool a little faster too.
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Post by Stinger on Jul 21, 2020 19:07:55 GMT -5
You're sort of lucky as it is since 25psi on 93 octane isn't typically possible with "normal" timing. Spooling faster increases cylinder pressure significantly and increased cylinder pressure is a driver of detonation (and hard on rods) so I wouldn't suggest doing that. Nitrous at high RPM would be safer.
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Post by RacingJake on Jul 22, 2020 12:00:05 GMT -5
A few months ago I put a Garret T3T4 48 AR on and man did it buck hard when it spooled, the car was slower to max RPM through the gears too so the next day I put .63 AR Garret back on and she's flying again.
I need to build a short block that can run up to 7K, that should keep me in boost when shifting and be a Hoot driving.
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Post by Stinger on Jul 22, 2020 12:54:02 GMT -5
Stock shortblocks can handle 7k.
If you want to stay in boost when driving then enable the flat shift feature or shift without lifting the throttle (and have your rev limiter set to a value a few hundred RPM above your shift point).
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Post by RacingJake on Jul 23, 2020 15:38:11 GMT -5
Dang and I thought I was pushing it's limits at 6.5 K
Thanks Shannon for all the advice !
Between you and Bo, you guys are a wealth of information and make a newbie turbo guy look good.
Jake
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