matth76

Hi

I had a rolling road session a few weeks ago on my remapped hawkeye STI type UK and have just come across another sheet amongst my results which shows what appears to be my BHP and another line which I'm not sure what it refers to. I assume it's my boost pressure as it says "bar_g" down the right hand vertical axis. Is this my turbo boost pressure? And if so does it all look ok? If this is my boost then my peak boost (1.35 bar) appears to come in at 3900 rpm. Is this pretty much normal or should peak boost come in a bit earlier?

From then on up to the redline at 7000rpm it appears to lose 0.35 bar, levelling out at 1bar. Is this decrease in pressure normal too or should it remain fairly constant at max boost ie 1.35 all the way up to redline?

Here's my graph:



Thanks for any help.
Cheers
Matt

GC8Fin

iTrader: (7)

The graph is showing you boost pressure and it looks normal, so i dont think you have much to worry about

matth76

Thanks for your reply. My car is fairly standard other than PPP and remap. If I fit a decat downpipe (meaning the car is then totally catless) and further remap, will my peak boost come in closer to the 3000 rpm mark? If so, what is realistic? Thanks again.

GC8Fin

iTrader: (7)

You would prob see some gains but i dont think it would reach peak boost under the 3000rpm mark

Don Clark

Matt,

Charlie usually gives you 4 printouts........

Power and Torque at the flywheel
Power and Boost
Power and AFR
Power and Torque at the Wheels

Most mappers reduce the boost level towards the redline.
It may be possible to bring peak boost lower down the rev range but probably not as far as you are asking.

Best person to ask would be Simon (JGM) who I assume remapped the car.

Edit : just viewed your garage - Race Dynamix remap so maybe speak to Duncan.

matth76

Thanks guys. I'm still learning All interesting stuff. If I fit a decat downpipe what rpm would my peak boost reaslistically come in at?

jura11

iTrader: (7)

In spool maybe worth ask here Harvey which selling Up pipe with OE ported headers,with this combo you will see earlier boost.

Downpipe will bring more bhp,not sure boost maybe little bit,but nothing special,for better/earlier spool you are need Harvey up pipe with OE ported headers


Jura

dynamix

iTrader: (3)

Peak boost on the road and peak boost on the dyno are two different things Matt.

They always tend to make boost later on the dyno.

The VF43 on yours is not big enough to hold onto that boost level fuurther to the top end but with the decat will hit 1.4 bar by 3000rpm on the road.

matth76

Thanks Duncan. From memory do you know what rpm on the road my peak boost is currently coming in approximately?

dynamix

iTrader: (3)

from memory you are getting 1.4bar at 3001 rpm







oh ok i cheated and looked at the datalogs

matth76

lol . Thanks. Does a decat downpipe not make a huge difference when peak boost comes in (if my current peak boost is around 3k rpm on road already and a decat will see me hitting peak also at 3k on road)?

dynamix

iTrader: (3)

There is a difference in by 3000 and at 3000

It is a lot livelier without the cats on there

Terminator X

iTrader: (7)

Boost below 2bar = ghey in my book

TX.

dynamix

iTrader: (3)

matth76

I'm still trying to work out the difference between in "by" 3000 and "at" 3000. Only 'cause I like to work things out. However I still can't work it out what you mean lol I am new to turbo cars .

Closest I assume you mean is a decat does not make the peak boost come in any earlier but still makes 1.4 bar by the same 3000 mark but the boost keeps on increasing after this rpm mark? However does the boost start coming in earlier - if so approximately how much earlier? My boost currently seems to start around 2800 rpm on the road.

On a side-note, do you think the hesitation issues I've had when the car is cold and still have re-occurring every other day, mainly when cold, could be due to tired spark plugs (which haven't been changed in over 30k miles)? Is it a good idea to change them prior to the remap? I'm away on hol next week as you know but going to get this all arranged before I go away, plugs if necessary, then decat and remap. I've already got the cosworth panel filter ready Cheers Duncan.

dynamix

iTrader: (3)

Meaning before 3000 rpm Matt You will notice a big difference in the car

Plugs will only help it - try putting some NGK 7's in there. They arent the normal PFR7B plugs for yours - it needs the longer nosed ILF7H plugs.

matth76

Hi Duncan. Thanks. Does Subaru normally use NGK grade 6? NGK's site only lists the part ILFR6B but their site is pretty limited. Is the higher the number the colder or more effective the plug? Are these one of the best I can get for my vehicle's planned mods? Thanks again

WRX Blues

Just looked at my graph from a JGM re-map (Spec D + PPP). Similar boost but peaks around 500rpm before yours?

dynamix

iTrader: (3)

The 7 grade plugs are a better option for your car Matt.

The code i list above is the correct one for your car. It is actually shown on the NGK site as an evo plug.

dunx

iTrader: (3)

+1

matth76

Thanks I've ordered the plugs you recommended. Car was playing up yet again on way home today. Not really hesitant this time, just a lot less power. Still very quick and still quite smooth in fact but probably 30% down on power and power only really comes in above 3500 rpm. Could my MAF sensor be causing these kinds of symptoms? Are new plugs likely to solve this?

matth76

That's strange although I assume it would be down to the different rolling road you went on as I know different rollers all produce quite different outputs sometimes.

matth76

Could the knock sensor be at fault?? Just read this thread on another forum http://www.imprezasport.net/forums/i...?showtopic=785, its a classic but very similar symptoms and apparently a straight forward cure, although I doubt the engine layout and knock sensor is the same in the hawkeye for me to be able to try this out but it could be a dodgy sensor. Anything I can try?

matth76

Anyone?

Jolly Green Monster

iTrader: (4)

You can fault find and diagnose everything over the net.

Imho it doesnt sound like a sensor issue

dynamix

iTrader: (3)

Matt. We will datalog exactly what is going on in a couple of weeks. Changing parts based on someone else's problem solving will only lead to confusion and unnecessary expense.

dynamix

iTrader: (3)

Ps it might be an idea for me to meet you at your work so that the car is cold

matth76

Hi Duncan. Thanks. I'm away on holiday all of next week but back very early Sunday 12th so am available that afternoon and car will have been sat for a week so be very cold. Im also available every evening or at my work that week.

Is it advisable to postpone fitting my decat downpipe (which I'm having done Sat 18th) until we can resolve this issue?

dynamix

iTrader: (3)

Matt. Will see if I can head down on the 12th. Leave the decat booking as is though til after we can track down what it is.