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Discussion Starter #1
I swear I saw a thread regarding boost on the stock TT HG a few days ago but I can seem to find any information with the search sucking lately. It seems 1 bar would be OK on pump (93) but how much on race gas? Also, what should timing be set at?
I would appreciate any information. Thanks in advance.

TT HG
60-1
MAP ECU
550cc injectors
250 Walbro

Any ideas? I should be getting it tuned shortly and would like to know how far I can push it.

Regards,
Nick
 

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173 Posts
Each car will be different, so tune it accordign to your car.

I was running 16PSI on a somewhat similar setup. T61 w525cc injectors on TT HG. I say was, because I cracked a piston (not due to the boost, but a bad part, ring land cracked out) So now I'm going to be running TT pistons and a TT HG.
 

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Time for change
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ring landings break because knock on hypereutectic pistons. So either that was a bad tune, or by bad meaning timed to agressivley for the street, or you had a fuel hiccup.
 

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If that was the case I'd say it was most likely a timing issue. The AFR tune was perfect at 11.5 across the RPM range dropping to 11.0 at 6600, or it was a fuel Hiccup as I am just now replacing the stock pump. From the look of the break though it was an old crack that was finished off do to new amount of boost added. The break had old wear inside it and the casting had cavity holes in it. The motor also had 115,000 miles and I'm the 3rd owner, so I'm guessing it was more an age/wear issue finished off by a timing/stress issue.

Beau - Thanks for the info. I'll store that away for future use. I'm guessing the air temp/humidity change (got warmer since the tune) and a slightly aggressive timing setup definitely finished off an old "injury" to the car.I didn't have knock during the tune. (street tuned and dyno checked).
 
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