standard boost gauge

[Kieron]

New poster! (less than 10 posts)

Hey, does anyone know what each marker on the standard boost gauge represents? Lol sorry for the anal question but I really don't want to put an aftermarket boost gauge in, I've seen an image that labels the markers from A-E but it doesn't label the markers in the red zone if you like, where all the markers are really close to eachother??? Can someone shed some light :-D thanks

[Trevhib]

The markers are not intended to represent specific boost levels, you can only approximate what pressure each one equates to.

You've seen the description here picture right?
http://www.renault5gtturbo.com/maintenance.htm

Those figures are true for the gauge they used to do that test on many years ago, who knows if yours is the same? Also, to be honest I think those figures are a bit low, based on experience.

But you can use that diagram as a guide. You can see how much A-E increments in pressure (noting that it's not a linear scale), and simply imagine F, G, H and I and work it out (as it will only ever be approximate).

If you are running a standard T2 you don't need to go much beyond E anyway as it's best not to run much more than 1bar (14.7psi) through it. And if you have a bigger turbo and are running more boost then you need an after-market gauge to ensure you're properly in control of what level you're pushing anyway.


Edit: For what it's worth, I think the end of the gauge is about 21psi at the carb top.

[Kieron]

New poster! (less than 10 posts)

Thanks for the reply I'm asking because I have a bigger turbo that I'm about to fit, along with rejetting my carb, I may just buy and use an aftermarket one to set it up then remove it, if the original isn't that accurate higher up the scale, because I want the car to look as standard as possible.

[juha5gtt]

Tested. End of the gauge thin line is 1.2 bar so approx. 17-18psi.
Beginning of thin lines are 0.9 bar. Both are Carb top results.
Phase 2 Renault 5 boost gauge. 1.4b and 1.5b in gauge are end of gauge far from last line..

[Trevhib]

New poster! (less than 10 posts)

Thanks for the reply I'm asking because I have a bigger turbo that I'm about to fit, along with rejetting my carb, I may just buy and use an aftermarket one to set it up then remove it, if the original isn't that accurate higher up the scale, because I want the car to look as standard as possible.

No worries.

Yes, if you are serious about tuning your GTT safely and reliably and you are changing the turbo and the carb jets, then the bare minimum you need is an after-market boost gauge and an AFR gauge.

I can understand the desire to want to run the standard look. So once you have tuned the car and thoroughly tested it, you can ditch the after-market boost gauge and use the OE one as a fail-safe. By then you will know where on your OE gauge your new set-up should be running to, and therefore know if something goes arwy. It's not that the OE gauge is inaccurate at higher levels, it's that you don't know what boost the lines equate to. Juha's post is a useful guide, although he's using the words like approximate but also he's testing on his 25yr old gauge and you'd be hoping your 25yr old gauge is the same.

Getting rid of the AFR gauge afterwards is more of a risk. Maybe you could leave the fittings in place (hidden), and remove the gauge itself so your look is still OE and plug it back in at periodic intervals just to check your set-up is still where it should be?

[Kieron]

Yeah I agree it's definitely the best way to go, I definitely don't want to modify and set it up incorrectly, good idea about keeping it in a discreet place, saves all the hassle with reconnecting everything and gives me an easier reading to understand/aaccuracy. Thanks everyone for your advice.