Club G40 Forum
Technical => Superchargers / G-Lader => Topic started by: Oli b on August 05, 2011, 06:18:26 pm
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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
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Yes. My R1 charger was boosting 14/15 psi and near redline was getting 18/19psi.
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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
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1.1 bar, ported myself with 65mm pulley.
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Are you guys using toothies or standard v belts?? Or have I just got a massive boost leak??
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Toothies.
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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.
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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.
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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.
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Used to get 14psi at the red line on my old G with a 65mm pulley and tight v belts (PSD Full Blend)
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It does depend a lot on the rest of the engine. My R1 used to pull 17psi on a stock engine.
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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
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i get 10psi on a jabba stage 4 charger with standard pully
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if u have had a stage 4 rebuild do u need the higher co pot sensor?
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the what? shouldn't have to do anything to the CO pot.
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i get 9/10 psi with a standard charger that needs a rebuild and running a 65mm pulley with jabba chip and g60 style belts and the gt inlet
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i get the same 0.9-1bar near red line with a 65mm pulley,r1 charger,standard v belts with beltslip spray on them
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i would have thought you would get more with the r1 charger , i dont know if i should rebuild mine or go for the r1!
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their all about same to be honest from what i can tell,my mates got a full blend and he's running about the same.
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Don't forget that if you've got ported bits your boost may drop relative to others.
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theres a big difference from 9psi to 0.9 bar - 1 bar is 16psi.
You see about 0.2 bar difference with a ported charger
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I thought one bar was 14.7 psi ?
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I thought it was 14.5?
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14.5...ish
http://tinyurl.com/bpx9jyp
Sorry Pete!
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Normally 1 bar is seen as the pressure of the earths atmosphere at sea level, which is 14.7 psi, but 1 bar actually equates to 14.5psi.
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Justin - you're confusing bar with atmospheres. Bar is an SI unit, so its definition doesn't change, atmospheric pressure at sea level is about 1013mBar.
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Yes, and 1atm is 14.7psi - which is why people think 1 bar is 14.7psi - because 1bar usually is just accepted as the pressure of the atmosphere. hence the misconception.
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my bad - 14. whatever.
even so... 9 psi wth a 65 is low
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Would 1225 Torr sound better? lol.
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i thought it was i may just rebuild this standard one unless i find a cheap r1/full blend
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Im glad this tread is going. Wanted to ask about my boost
Mods on engine.
Rebuilt r1 2k ago, 51mm polished throttle body, ported polished gt inlet, 65mm psd phase1 toothies, 1341cc, pace intercooler with minium bends, lightend & balenced bottom end, psd uprated injectors, sns stage 5 chip, light porting and polished head. Etc. Mine hits 20-21 psi on my digital glow shift gauge, at 7k is that about right.
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that sounds way off to me! assuming that you're talking about the normal g40 charger and you've not fitted a g60, then I'd be surprised if it was making more than 13-14psi. Things like 51mm TB, GT inlet will actually reduce the boost pressure you see on a gauge because more air is going into the engine.
it can't be making 21psi with a g40 g-lader.
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Yea g40 r1. Ive been told its high but cant understand why its reading that high.
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I'd try a different gauge
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I'd try a different gauge
x2 sounds whey to high for the spec
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De wedged throttle, 65mm pulley, standard charger new vee belts, unknown chip and mine makes 10psi at 7k?
i see some people are getting around 15 psi with the same mods?
would a worn charger cause that much drop as i dont know when it was last serviced
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you wont get that high with a stock charger... you'd get 0.8 bar max... comparable to about 1bar 1.1bar with a fully ported unit
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Ah, thanks for that. has put my mind at ease, thought the charger was on its way out and in need of a rebuild
i didnt realize a fully ported made so much difference
thanks mate