Missing Boost

pokeyl · 08-23-2013, 03:05 PM

I will look, I would think that a low oil flow would have destroy the SC.

Rotrex wants the belt changed and a smoke test for leaks after that.

The belt is old, my SC makes a high pitch whistle, I always though it was intake noise, I hope it is just a belt. Autozone will have one here tomorrow.

pokeyl · 08-23-2013, 11:32 PM

Inspected the belt, cracked, dusty and looks like it may be at the limit of the tensioner. So I stoppeed at Autozone and sprayed the belt with dressing. Boost now seems constant 3 lbs at 3K. It was raining and the racelogic had its hand full. Will test more this weekend with the new belt. If I hit over 10PSI I'll call it good.

pokeyl · 08-25-2013, 02:53 PM

Installed new belt, it is a 1045K7, GTM spec.

It looks longer than the one I pulled off. Belt wear indicator is not in range.

I had no squeal fro the first 20 seconds and then it came back. I think my belt is too long.

What a pain to change...

Now looking for a 1040 or 1035.

Sh0velMan · 08-25-2013, 03:02 PM

Quote:

Originally Posted by pokeyl

Installed new belt, it is a 10454K7, GTM spec.

It looks longer than the one I pulled off. Belt wear indicator is not in range.

I had no squeal fro the first 20 seconds and then it came back. I think my belt is too long.

What a pain to change...

Now looking for a 1040 or 1035.

In my experience, it's really hard to find a 7PKXXXX belt if you need a non-standard length.

I ended up going with a 6PK (6 rib rather than 7) and it works fine.

Here's a 6PK1035 Amazon.com: Bando 6PK1035 OEM Quality Serpentine Belt: Automotive

pokeyl · 08-25-2013, 10:53 PM

Quote:

Originally Posted by Sh0velMan

In my experience, it's really hard to find a 7PKXXXX belt if you need a non-standard length.

I ended up going with a 6PK (6 rib rather than 7) and it works fine.

Here's a 6PK1035 Amazon.com: Bando 6PK1035 OEM Quality Serpentine Belt: Automotive

What pulley are you running?

Underdrive crank pulley?

I can find 1040K7 and 1030K7, but no 1035K7 is this the one I need with a standard crank and the small GTM pulley or will the 1040K7 be short enough? 1045K7 looks long.

What is the difference from the 7PKXXXX and the XXXXK7 belts?

pokeyl · 08-26-2013, 07:40 AM

Did not work, as soon as SC fluid got up to temp boost fell off 6 PSI max and starts to build after 4K (1.5 to 2 PSI) and you have to twist past 6K to get to 6 PSI.

When the fluid is cold I build boost at 3 PSI at 2-3K...

pokeyl · 08-29-2013, 07:11 AM

Worked good 75F OAT for 45 min, 60-70 MPH. As soon as I hit city stop and go oil got to hot and boost fell off.

I am going to work on adding airflow to the coolers fan system.

Note: the under hood temp will burn you on any item you touch. The SC fluid in the tank is 155-160F (after a 1.5 hour heat soak drive and a 15 min cool down)
I took me 15 min to find my thermometer.

During the 15 min cool down the oil temp fell from 220 to 190F. If the SC fluid fell the same amount, my max temp is 185-190F is over the rotrex 175F limit.

pokeyl · 11-06-2013, 03:12 PM

Just got back home and spent the last 10 hours changing my SC unit. Fluid looked BAD milk/gray. Hope this fixes the boost falloff problem.

Then I can start back on this!

elperuano · 11-06-2013, 10:27 PM

How many miles on the SC?

pokeyl · 11-07-2013, 09:14 AM

Quote:

Originally Posted by elperuano

How many miles on the SC?

15K on my car, but I bought it used from a 370z member/vendor and it was bad when he sold it to me. I took me 18 month to find out what was wrong.

I would have saved $2K if I had just bought a new one from GTM!. I was not trying to save the money, I was trying to help a member out.

No good dead goes unpunished!

pokeyl · 12-21-2013, 08:48 PM

I don't know if anyone is following this but the SC change did not fix it. But today I started looking at the "tune" as the car ran fin as a Stage 1 and never as a Stage 1.5 and after looking for hours I found the problem?

See the highlighted line, is is set to "off" in the 1.0 tune and "on in the 1.5

I understand that all 3 of the codes in this frame need to be set to off (FI cars) or you will get a "LIMP MODE" AKA missing boost as the throttle is 20% MAX

pokeyl · 12-23-2013, 10:28 AM

Fixed

After a new BOV, belt change Pulley change, Supercharger change, leak test and many other things. It was the tune. Thanks for all the help.

Mkai0 · 12-23-2013, 11:42 AM

Thank you for sharing your progress.

08-23-2013, 03:05 PM	#31 (permalink)
pokeyl Track Member Join Date: Nov 2010 Location: DFS Posts: 897 Drives: ??? Rep Power: 55	I will look, I would think that a low oil flow would have destroy the SC. Rotrex wants the belt changed and a smoke test for leaks after that. The belt is old, my SC makes a high pitch whistle, I always though it was intake noise, I hope it is just a belt. Autozone will have one here tomorrow. __________________ It's not my fault I'm old, I was born a very long time ago!

08-23-2013, 11:32 PM	#32 (permalink)
pokeyl Track Member Join Date: Nov 2010 Location: DFS Posts: 897 Drives: ??? Rep Power: 55	Inspected the belt, cracked, dusty and looks like it may be at the limit of the tensioner. So I stoppeed at Autozone and sprayed the belt with dressing. Boost now seems constant 3 lbs at 3K. It was raining and the racelogic had its hand full. Will test more this weekend with the new belt. If I hit over 10PSI I'll call it good. __________________ It's not my fault I'm old, I was born a very long time ago!

08-25-2013, 02:53 PM	#33 (permalink)
pokeyl Track Member Join Date: Nov 2010 Location: DFS Posts: 897 Drives: ??? Rep Power: 55	Installed new belt, it is a 1045K7, GTM spec. It looks longer than the one I pulled off. Belt wear indicator is not in range. I had no squeal fro the first 20 seconds and then it came back. I think my belt is too long. What a pain to change... Now looking for a 1040 or 1035. __________________ It's not my fault I'm old, I was born a very long time ago! Last edited by pokeyl; 12-05-2013 at 10:36 AM.

08-26-2013, 07:40 AM	#36 (permalink)
pokeyl Track Member Join Date: Nov 2010 Location: DFS Posts: 897 Drives: ??? Rep Power: 55	Did not work, as soon as SC fluid got up to temp boost fell off 6 PSI max and starts to build after 4K (1.5 to 2 PSI) and you have to twist past 6K to get to 6 PSI. When the fluid is cold I build boost at 3 PSI at 2-3K... __________________ It's not my fault I'm old, I was born a very long time ago!

08-29-2013, 07:11 AM	#37 (permalink)
pokeyl Track Member Join Date: Nov 2010 Location: DFS Posts: 897 Drives: ??? Rep Power: 55	Worked good 75F OAT for 45 min, 60-70 MPH. As soon as I hit city stop and go oil got to hot and boost fell off. I am going to work on adding airflow to the coolers fan system. Note: the under hood temp will burn you on any item you touch. The SC fluid in the tank is 155-160F (after a 1.5 hour heat soak drive and a 15 min cool down) I took me 15 min to find my thermometer. During the 15 min cool down the oil temp fell from 220 to 190F. If the SC fluid fell the same amount, my max temp is 185-190F is over the rotrex 175F limit. __________________ It's not my fault I'm old, I was born a very long time ago! Last edited by pokeyl; 08-30-2013 at 09:21 PM.

11-06-2013, 03:12 PM	#38 (permalink)
pokeyl Track Member Join Date: Nov 2010 Location: DFS Posts: 897 Drives: ??? Rep Power: 55	Just got back home and spent the last 10 hours changing my SC unit. Fluid looked BAD milk/gray. Hope this fixes the boost falloff problem. Then I can start back on this! elperuano and luigi90210 like this. __________________ It's not my fault I'm old, I was born a very long time ago!

11-06-2013, 10:27 PM	#39 (permalink)
elperuano A True Z Fanatic Join Date: Oct 2011 Location: Southwest FL Posts: 1,374 Drives: G37S Rep Power: 29	How many miles on the SC?

12-21-2013, 08:48 PM	#41 (permalink)
pokeyl Track Member Join Date: Nov 2010 Location: DFS Posts: 897 Drives: ??? Rep Power: 55	I don't know if anyone is following this but the SC change did not fix it. But today I started looking at the "tune" as the car ran fin as a Stage 1 and never as a Stage 1.5 and after looking for hours I found the problem? See the highlighted line, is is set to "off" in the 1.0 tune and "on in the 1.5 I understand that all 3 of the codes in this frame need to be set to off (FI cars) or you will get a "LIMP MODE" AKA missing boost as the throttle is 20% MAX jaytirbhaw and Mkai0 like this. __________________ It's not my fault I'm old, I was born a very long time ago! Last edited by pokeyl; 12-21-2013 at 09:11 PM.

12-23-2013, 10:28 AM	#42 (permalink)
pokeyl Track Member Join Date: Nov 2010 Location: DFS Posts: 897 Drives: ??? Rep Power: 55	Fixed After a new BOV, belt change Pulley change, Supercharger change, leak test and many other things. It was the tune. Thanks for all the help. Mkai0 and jlo370z like this. __________________ It's not my fault I'm old, I was born a very long time ago!

12-23-2013, 11:42 AM	#43 (permalink)
Mkai0 Base Member Join Date: Dec 2010 Location: Somewhere in Texas Posts: 209 Drives: 2008 G35 Sedan Rep Power: 14	Thank you for sharing your progress. __________________ Eibach, Tanabe, Blitz, Vertini, GTM stage 1.5 SC, Aquamist, Invidia, Alto built 5AT, Edge Racing, Racelogic, GTM driveshaft, 440 whp in 101F TX heat..

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