Hi all. Recently had my 20VT on the rollers at weston performance, would like a bit of advice really if poss. The car is standard with exception of a GTech-1, PRV, pace smic and a K+N panel in a drilled 'box. Half my fuel was sainsburys 95ron , half was esso 97 ron.

The main reason i had it on the rollers was to check fuelling - it was ever so slightly lean coming on boost but the operator said it was nothing to worry about. I thought the boost was at 1.2 bar but my gauge must be crap as it was actually 1.1. This tailed right off to 0.65 by the redline though, this seems low to me? Boost leak somewhere? The boost also spiked on the second run so a new prv is in order i'd say.

The car made a peak of 243.2bhp - does this seem about right for a 1.1bar GTech'd 20vt? Torque peaked as it came on boost at just over 250ft/lb and held well until about 5000rpm where it started to tail off to about 175lb/ft by the redline. Normal?

Im quite happy with it i think, although it would be nice to see over 250hp really. Would 1.2 bar see me there (with decent fuel? )?

I'll get the graph up tonight. TIA.
Toby.

GRAPH ADDED; http://img.photobucket.com/albums/v489/tob4312/RRplot1.jpg

I would trust my boost gauge over what the RR graph says, on my graph the boost didnt go over 1 bar until 4000 rpm, which is complete rubbish as its on full boost just over 3000 rpm out on the road.

often you will get different boost on the rollers to what you do on the road! on the rollers your gauge may have also showed 1.1 bar!

also to eliminate boost spikes i would suggest an EBC rather than a PRV!

Id trust their gear over my £9.99 Equus gauge though It was accurate for others on the day.

There's no way i can afford an EBC, not a chance! It only actually spiked on the second run.

Here's the plot, both runs, second run in blue, you can see the spike obviously on the torque curve. Unfortunately they didnt print off the afr/boost, but as i said - it was 1.1bar, tailing off to 0.65 at the redline on their equipment.

http://img.photobucket.com/albums/v489/tob4312/RRplot1.jpg

Any other views on this? I still think there might be a boost leak, boost tailed off too far in my eyes although i'd like another opinion really.

Did they give you a boost graph or purely the power/torque?! It does seem to tale off fairly quickly.

Do you know what boost you are holding according to your gauge higher up the revs?!

A way of checking will be to put your two pipes together that go into your PRV and see what boost you are holding. If it's a standard actuator is 0.6 bar, so you ideally should be able to hold that nearly all the way through the revs, giving your base boost. If it's drops by much, you've probably got a boost leak.

Mark

They only supplied the graph above which was a shame. So it does look like it tails earlyish? Thanks for the suggestion, i'll give it a try. Actually, iirc, with my prv wound all the way out it will have the same effect as the spring wont put any pressure on the bb, might try that tomorrow. I think my gauge says about 0.7ish at the redline although i rarely watch my gauge to the redline for obvious reasons, lol.

TT here is my Graph. I have a standard car with Gtech 1 and that is it . There is a boost spike to 1.4 bar but is nothing to worry about. I have a PACE smic to fit this holidays but will do no more than that. Car back with standard Fiat chip now and getting a RR session done in January for comparison.

It would be noce to have both chips and ability to switch between the two.

John

Blimey, result! Well done mate, thats impressive! Late coming on boost though isn it? Seems pretty certain mines leaking from somewhere then if thats a standard setup. I'll replace my gauge with a decent one, get a new prv (reccomendations? ), new DV and check all the piping carefully and try her again at 1.2bar, see how she does. Thanks, thats helpful to be able to compare side by side!

I'm pretty sure the operator has stopped your run quite short of the redline.....though I dont think this would have affected your power reading as the boos tails off. Your result is pretty good for 1.1 bar - remember the standard turbo can't hold boost at the top of the rev range anyway, and if they are reading 0.65 at the 'redline' and 1.1 bar when your gauge says 1.2 then you could be running 0.75 - which is fine.

The boost spike is tiny - nothing to worry about at all! Dont get hooked up with 'I must get over 250bhp'. Another 10 bhp is not going to transform the car on the road.