just installed boost gauge

[spooneyg40]

just installed a brand new boost gauge autogauge.. and is reading 7 psi max does this sound right? car spec below.....(copy'd from old 4 sale thread..

jabba stage 4 charger

ECU has been remapped to suit the smaller pully and charger.

Standard Airbox fitted with K&N washable panel filter.

Boost return mod carried out

Engine out, engine bay cleaned, any dirty/rusty bits cleaned and sorted.
Engine striped down, block repainted in black, all water channels etc flushed.
New cambelt and waterpump.
All inlet gaskets replaced, exhaust gaskets replaced, sump dropped, cleaned out and powder-coated. All engine mounts/brackets/plates/ metal waterpipe, removed and powder-coated.
New genuine platinum plugs fitted with new leads/cap/rotor and also new ignition coil.
Gearbox oil changed.
New clutch fitted with mk4 Polo 16v 200mm clutch plate
Brand new Cooper cored radiator
Wiring loom completely re-taped.
Boost pipes replaced with black silicon hoses.
New thermostat housing with new temp sensors and thermostat
Intercooler degreased and pressure tested and repainted.
New front wheel bearings, struts repainted, brake calipers painted, caliper carriers powdercoated rear brake dust shields powder-coated. New Gmax gas struts. Replaced top mounts and ARB mounts with genuine items.
ARB mount brackets and ARB itself powder-coated.
Drilled vented disks fitted with Padgid fast road pads. Goodridge braided hoses and all new fluid.
Stainless downpipe polished (G40s came with stainless downpipes as standard!) and Decat pipe fitted.
Longlife stainless backbox with original stock look tailpipe, polished.

[Robin]

No - you should be seeing 12-14psi.

[spooneyg40]

any ideas as too what could be causing the low boost? i know it could be kinda a guessing game

[z3i]

Seems a bit low :/
Mines putting out 10 psi with a 65mm pulley and lightly ported charger with dodgy leaky boost hoses

Do you know what size the pulley is? and is it the standard twin v belts?
Check the tension of the belts as they may slip at high rpm
if the guy has had the intercooler off it may be worth checking all the jubilee clips are tight
Taylor

[spooneyg40]

yep standard v belts with 65mm pulley, they are a little slack but what tension should they be? surly not frayp'd right up also its boosting at 7 psi from go pretty much to around 5500 rpm 6000rpm i try not to push past this really

[spooneyg40]

i just asked the guy i bought it from if he knew any reason why its running low, he reply;d "who said it should be running, 12-14 psi, if it was running that then it would be have to be around 160 bhp"

[z3i]

yep standard v belts with 65mm pulley, they are a little slack but what tension should they be? surly not frayp'd right up

Well i put new original ones on mine and adjusted them as tight as i could possibly get it, and they still felt a little slack.
they are meant to be pretty tight.

Theres a half inch slot in the charger for use of a breaker bar to adjust it, gives more leverage. doesnt take too long to do. though you will need a 90 degree 10mm allen key (pretty sure its 10mm), and you will need to grind it down a bit so it fits in the charger to exhaust manifold bracket, thats to only bit i struggled with
Taylor

[z3i]

Just because your running 12-14 psi it doesnt mean more power. people on here are running lower boost with other mods like, big valve heads, ported throttle boddies and inlet manifolds, this will bring boost levels down

[spooneyg40]

thanks for the advice dude, i get those slack belts tightened and repost with results, hopefully il see n maybe fell a difference as he said it was ages ago they were tightened, even a friend commented on how slack they are...just weird that it really takes off n pulls so well even tho they are pretty slack....

[PeteG40]

Check your boost hoses for leaks--- charger to intercooler is prone to holing if original

[z3i]

Contact the man above for new belts should you need them. i snapped mine and he got some sent out straight away at a really good price

Happy to help
Taylor

[spooneyg40]

will do but im currently looking for toothed belt with 65mm pulley if anyone can help?

[grungeisdead]

0.7 bar is the factory boost iirc, and 7psi is around 0.5 bar so its deffo not right.

tightening the belts makes a massive difference if they are slack, happens alot with standard v-belts, as said Pete can get you new ones really cheap.

sounds like your previous owner doesnt know thier arse from thier elbow

[spooneyg40]

ok so iv tightened the belt although 1 feels slightly slacker than the other, went for a drive n put my foot to the floor.....................FUCK ME what a difference...it actually made me shit myself for a few seconds as to how much extra boost iv got!! boost gauge now boost to about 14 creeping toward 16 -17 near the red...so chuffed ad happy i didnt realise how quick my g40 was...big smiles thanks guys