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Questions about my GT28R-what boost should it hold
#883561
15/08/2009 15:59
15/08/2009 15:59
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Joined: Mar 2006
Posts: 135 South east
Rob
OP
On a journey
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OP
On a journey
Joined: Mar 2006
Posts: 135
South east
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As the title suggests, I need to know what kind of boost I should be expecting to see from a GT28R.
I currently have one fitted on the car, with a 2.5" exhaust system inc decat. The inducion is standard until next week. After taking advice on fueling etc on here, I decided to take it to Leighton a couple of months back for some mapping. This produced results of 260bhp @ 1.1 bar via a mbc. Although this is a decent enough figure, i was expecting a little more. I dont have the graphs to hand right now, but I shall update as and when I can.
My issue is that I have an insane amount of lag. So much so that i'm hitting 1.1bar at about 4200 maybe just a tad later. This may not seem too bad to some people on here, but the fact that my boost trails off to 0.7bar at the redline kinda makes it a little undriveable. You have to wring its neck everytime you want some power, and then when you get it, it kinda tails off.
Apart from a boost leak, what else would cause my boost to tail off?
Can someone on here with a simalar set up let me know (or knowelegeable people) what kind of boost I should be seeing at 4k, and what I should be seeing at the redline? The turbo seems to be acting more like a very lazy standard turbo, but not holding boost high up the rev range as i assume it could.
Cheers in advance.
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Re: Questions about my GT28R-what boost should it hold
[Re: Rob]
#883641
15/08/2009 19:34
15/08/2009 19:34
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MattW
Unregistered
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MattW
Unregistered
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My old one got full boost of 1.4 bar in the mid 3000s and didnt drop below 1 bar at 7000rpm. Sounds like you might have a boost leak or a restriction, maybe in the intercooler.
What other mods do you have?
I found that a manual boost controller was pretty rubbish at controlling the GT28R so I bought an AVCR which was amazing. I dont know exactly how much of it was down to that though as I changed other things at the same time.
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Re: Questions about my GT28R-what boost should it hold
[Re: Nigel]
#883671
15/08/2009 20:35
15/08/2009 20:35
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MattW
Unregistered
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MattW
Unregistered
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Another thing it could be is incorrect adjustment on the wastegate. If the actuator arm is too long then the wastegate wont be tightly shut when it's spooling up.
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