I have an air leak

babbagandu · 08-07-2012, 10:35 AM

So I had my motordyne m370 and stillen g3 installed and got an uprev dyno tune maybe a month ago.

Ever since then I noticed a weird "popping" noise at low rpm's as I am taking off or just lightly pressing the throttle. Sometimes it even just makes the noise constantly while idling, but only rarely. I was at a muffler shop for something else and asked the guy and he said I had an intake leak, possibly a vacuum hose.

I'm gonna go to a regular mechanic (not the shop that installed and tuned) to take a look at it but my question is if my car was dyno tuned when it had the leak, will I need to have it tuned all over again once it is fixed?

babbagandu · 08-07-2012, 10:37 AM

Oh and also, could this have caused any damage to my motor?

SS_Firehawk · 08-07-2012, 11:27 AM

I had a bad install on an M370, with a bad seal. It ran for a couple days before I got it back in. I didn't see any detrimental affects stemming from that issue.

wstar · 08-07-2012, 12:05 PM

Well the vacuum and PCV hoses are easy to check yourself, just look around at all the hoses attached to or nearby the intake manifold and valve covers (2x PCV-related lines on each side, and brake booster vacuum in the rear. Check out the MAP sensor too, it should be plugged into a short hose on a T-adapter in the rear as well in an M370 config I think).

The worst will be what SS Firehawk mentions above: it could be the gasket between the M370 and the lower intake manifold moved at the last second during the install and got pinched and isn't sealing. It sits in a groove on the underside of the M370 and presses against a flat surface on the lower intake. No way to see it while installed, but it can easily fall out of the groove as it's hanging upside down just before they're pressed together. The seal should be lubed for install anyways though, and the lube should help hold it in the groove for a few seconds.

babbagandu · 08-08-2012, 08:05 AM

Thanks for the replies. Does anybody know specifically if another tune will be necessary?

SS_Firehawk · 08-08-2012, 12:17 PM

Not necessary, but there are minor AFR changes from running it. It's not completely apples to apples, but going from being tuned on the M370 to the stock, hp dropped from 304 to 300, with tq dropping from 243 down to 230. After I retuned for the stock manifold, those numbers both went up by 6 and 5 respectively.

08-07-2012, 10:35 AM	#1 (permalink)
babbagandu Enthusiast Member Join Date: Mar 2011 Location: US Posts: 349 Drives: 09 Nismo Rep Power: 14	I have an air leak So I had my motordyne m370 and stillen g3 installed and got an uprev dyno tune maybe a month ago. Ever since then I noticed a weird "popping" noise at low rpm's as I am taking off or just lightly pressing the throttle. Sometimes it even just makes the noise constantly while idling, but only rarely. I was at a muffler shop for something else and asked the guy and he said I had an intake leak, possibly a vacuum hose. I'm gonna go to a regular mechanic (not the shop that installed and tuned) to take a look at it but my question is if my car was dyno tuned when it had the leak, will I need to have it tuned all over again once it is fixed?

08-07-2012, 11:27 AM	#3 (permalink)
SS_Firehawk Premium Member Join Date: Oct 2011 Location: Tampa Posts: 4,142 Drives: 13' Magma Red Nismo Rep Power: 7335	I had a bad install on an M370, with a bad seal. It ran for a couple days before I got it back in. I didn't see any detrimental affects stemming from that issue. __________________ Old Car:GTM TSC'd 550whp / 410lbft tq @ 11.88PSI New Car: Under Construction

08-07-2012, 12:05 PM	#4 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Well the vacuum and PCV hoses are easy to check yourself, just look around at all the hoses attached to or nearby the intake manifold and valve covers (2x PCV-related lines on each side, and brake booster vacuum in the rear. Check out the MAP sensor too, it should be plugged into a short hose on a T-adapter in the rear as well in an M370 config I think). The worst will be what SS Firehawk mentions above: it could be the gasket between the M370 and the lower intake manifold moved at the last second during the install and got pinched and isn't sealing. It sits in a groove on the underside of the M370 and presses against a flat surface on the lower intake. No way to see it while installed, but it can easily fall out of the groove as it's hanging upside down just before they're pressed together. The seal should be lubed for install anyways though, and the lube should help hold it in the groove for a few seconds. __________________ 7AT Track Car! Journal thread / Car setup details

08-08-2012, 12:17 PM	#6 (permalink)
SS_Firehawk Premium Member Join Date: Oct 2011 Location: Tampa Posts: 4,142 Drives: 13' Magma Red Nismo Rep Power: 7335	Not necessary, but there are minor AFR changes from running it. It's not completely apples to apples, but going from being tuned on the M370 to the stock, hp dropped from 304 to 300, with tq dropping from 243 down to 230. After I retuned for the stock manifold, those numbers both went up by 6 and 5 respectively. __________________ Old Car:GTM TSC'd 550whp / 410lbft tq @ 11.88PSI New Car: Under Construction

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08-07-2012, 10:37 AM	#2 (permalink)
babbagandu Enthusiast Member Join Date: Mar 2011 Location: US Posts: 349 Drives: 09 Nismo Rep Power: 14	Oh and also, could this have caused any damage to my motor?

08-08-2012, 08:05 AM	#5 (permalink)
babbagandu Enthusiast Member Join Date: Mar 2011 Location: US Posts: 349 Drives: 09 Nismo Rep Power: 14	Thanks for the replies. Does anybody know specifically if another tune will be necessary?