Author Topic: G40 boost preasure  (Read 13131 times)

Offline Oli b

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G40 boost preasure
« on: August 05, 2011, 06:18:26 pm »
Hi my g40 engine has had 65 mm pulley jabbasport chipped ecu and stage 4 jabbasport charger ( rebuilt around 10k miles ago)
Boost gauge shows 0.9 bar when on full throttle and creeps up to 1.0 bar near the redline
Is that a good amount of boost for this spec ?
Cheers

Offline Jezza-7

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Re: G40 boost preasure
« Reply #1 on: August 05, 2011, 06:31:37 pm »
Yes. My R1 charger was boosting 14/15 psi and near redline was getting 18/19psi.

Offline ereeiz

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Re: G40 boost preasure
« Reply #2 on: August 10, 2011, 10:22:58 am »
About the same for me too, I get about 1.0 bar creeping to 1.1 near the limiter. Full blend, 65mm toothed belt kit and cheapo Autogauge boost gauge

Offline Richg40

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Re: G40 boost preasure
« Reply #3 on: August 10, 2011, 12:27:10 pm »
1.1 bar, ported myself with 65mm pulley.

Offline Jake G 4 0

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Re: G40 boost preasure
« Reply #4 on: August 17, 2011, 07:34:59 pm »
Are you guys using toothies or standard v belts??  Or have I just got a massive boost leak??

Offline Jezza-7

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Re: G40 boost preasure
« Reply #5 on: August 17, 2011, 10:12:15 pm »
Toothies.

Offline ereeiz

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Re: G40 boost preasure
« Reply #6 on: August 18, 2011, 10:03:27 am »
Think it peaked about 0.8 or 0.9 with 65mm pulley and tight vee-belts for ten miles or so then they'd slack off/stretch.

Offline hayesey

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Re: G40 boost preasure
« Reply #7 on: August 19, 2011, 09:36:13 am »
I never saw more than 15psi on mine when it had a g-lader and 65mm pulley with toothies on it.  I'd question the boost gauge accuracy if you are seeing 18/19psi on it :D

It went down to 13/14 when I put a gt inlet and de-wedged the throttle body, as you'd expect.

Offline Jezza-7

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Re: G40 boost preasure
« Reply #8 on: August 19, 2011, 09:42:56 pm »
Nothing wrong with my gauge. Think it would be rare for a stack gauge to be inaccurate.

My boost is now 10-11 psi, running 51mm tb, gt inlet, ported head and 1341 bottom end.

Offline Dan-G40

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Re: G40 boost preasure
« Reply #9 on: August 20, 2011, 06:01:19 pm »
Used to get 14psi at the red line on my old G with a 65mm pulley and tight v belts (PSD Full Blend)

Offline AlexG40

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Re: G40 boost preasure
« Reply #10 on: August 20, 2011, 06:24:21 pm »
It does depend a lot on the rest of the engine. My R1 used to pull 17psi on a stock engine.

Offline ereeiz

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Re: G40 boost preasure
« Reply #11 on: August 21, 2011, 10:58:09 am »
Remember the accuracy of the gauge too, I'd bet most the ones used are just naff cheap ones like mine :D So the components used will have poor tolerances and variations in results, so if you're a few PSI/0.1bar' off someone with similar/ same mods then i'd put it down to that.

Best way to tell is do an identical drive in the other car and swap gauges, see if you get the same results in both. Even then there's no guarantee that either is correct, they could both be off :p

Offline alan gorst

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Re: G40 boost preasure
« Reply #12 on: August 24, 2011, 02:07:55 pm »
i get 10psi on a jabba stage 4 charger with standard pully

Offline JIMMYP

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Re: G40 boost preasure
« Reply #13 on: October 03, 2011, 08:38:05 pm »
if u have had a stage 4 rebuild do u need the higher co pot sensor?

Offline hayesey

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Re: G40 boost preasure
« Reply #14 on: October 04, 2011, 10:39:34 am »
the what? shouldn't have to do anything to the CO pot.