T5NYW

iTrader: (4)

Before we start I realy love my PPP and ain't knocking it

I have PPP fitted and well pleased with it performance
I have notice non PPP'd Sti7 performance was fairly linear as in through all the gears, 4Krpm kick with a top speed(clock) as 160mph(not rpm). 6th gear pulls(Kick boost etc.)the same as 4Th or 5th etc.
Since I've change to PPP'd STi7 1st to 5th gears are Brill sixth gear over 120mph is comparitivly flat top speed 155mph(est). Just in case I wish to go on Autobahn or my mates private road again.

Is this just my impression or a Fact ? Is this a possible reason for peeps doing RR tests in 4th and not top and boost set up speed related. Or have I totally lost the Plot.

Tony

russell hayward

Mine seems ok and is holding 1.35/1.4 BAR.

However, I have noticed a distinct "holding back" at times in 5th and 6th over 4k rpm. Boost not being reduced, just a distinct lack of pull. Keep foot planted and after a few seconds it comes back again to normal.

Put it down originally to dodgy fuel but tried 3 different types and still doing it.

T5NYW

iTrader: (4)

Russ,
Perhaps Knock Correction (sounds like I know what I'am on about) and maybe should try Octane Booster, Silverstone Racing fuel or Aviation fuel LOL I have no guages so going by feel might just seem slow by comparison

Tony

Ps, not that I'd drive it at that sort of speeds of course but on an Autobahn

Dave T-S

Tony
I haven't found a local bit of road long enough yet but will report my findings if I do....

mutant_matt

Not really enough to go on TBH! How long have you been in 6th and at what speed or are you talking about a redline change up from 5th and continue accelerating and it hesitates? What were you doing prior to accelerating? Is there a chance that heak soak is the problem. How about if you cruise along in 6th @ about 60mph for a while to make sure there is no heat soak, change down into 5th, redline and then change up and keep going. Does it happen then? Worth a try? Failing that, get a Select Monitor or DD on it....

Dave, how about the M1 on Sunday morning on the way to the AGM?

Matt

T5NYW

iTrader: (4)

Matt,

Edited to remove details will Email you later

Tony

[Edited by T5NYW - 10/22/2002 6:06:11 AM]

Dave T-S

Matt
Too public for my liking (and I won't be on the M1 ).

The Haverhill bypass just needs to be a bit longer......

T5NYW

iTrader: (4)

Matt,
Sorry mate what is heat soak ?

I would say at flat 7k 5th the non PPP would be 10mph down compared with a PPP'd STi7 at the same piont on the road.
But at near 6K in 6th PPP'd sti7 seems 10mph down at the same piont of road. (sorry not good at explaining myself)

Tony

mutant_matt

Tony,

YHM back m8

Basically, It's hard to decipher what's going on based on your email so here are some thoughts. How long is the 30 limit? Heat soak in this context is when the heat from the engine heats up the Intercooler, heating up the air going into the inlet manifold (and presumably, some heating here from the manifold takes place also). To overcome this, you need to travel at a faster speed where the air flowing over the engine and through the Intercooler cools it down and therefore, the air passing through it. How long is the 30 limit? What kind of roads before that and how hard were you driving? When you get on boost, the Turbo creates a shed load more heat so heat soak increases. Usually, if you are producing more boost, you are going faster which offsets the extra heat going into the Intercooler and the net result is a cooler Intercooler and cooler air going into the inlet. So, if you've been driving for a while slowly (like in a 30 limit) then when you boot it into the national, the inlet temps might already be quite high. If you keep going hard on boost, by the time you are in 6th, accelerating hard, the Intercooler may have not been able to get rid of the original heat soak plus the new added heat. It's impossible to say without monitoring the inlet temps.

The easiest way to make sure is to drive at a good 60 for a while (several mins if possible) keeping it off boost as much as possible (in 6th). Once you've done this, change down into 5th and boot it to the redline, change up into 6th and keep going. See if it feels any better this way. (you will probably need an empty Motorway/DC for this or at least a very long straight road)

That's the best advice I can offer I'm afraid and the thing that bugs me is that in the same car pre PPP, you say the same (repeatable?) way of driving on the same road didn't cause this problem. Perhaps it's possible that the extra boost the PPP runs, in this situation means that the Intercooler can't overcome the rising temps like it could when you were running less Boost. See if you can try my test and see if it makes any difference. Failing that, get an Inlet Temp gauge/put it on a dyno and try and reproduce/put it on a Select Monitor/DeltaDash and see if you can figure out what is going wrong!

Any of the "real" experts (i.e. not me ) want to comment?

Hope some of this helps,

Ta,

Matt

T5NYW

iTrader: (4)

Matt,
Yes was driving hardish before the 30 then hard after. Sounds like you Heat soak theory. I didn't use the I/C spray as told ineffective unless outside temp 20*c + outside temp was 8*c.
I'll try your 60 then go the next time on my mates road I may try using the I/C spray before the 30

Tony