What has more hp 16.5 or 18.0 psi?

[phxscooby101]

Heres my setup 2.0 unichip,m2 uppipe, turboxs downpipe with
3in pipe the rest of exhaust no cats, injen intake, m2 intercooler+
bigger hoses, boost gauge,egt, knocklink. oh 5 speed, stock
turbo.

First Q is i've dragged my car on two seperate occasions most
runs are about 14.0 at 97or98mph, my best is 13.7 at 98mph.
most of the time i run the boost at 1.2 bar max in like 3rd gear
and somewhere between 3000 to 5500 at 1.2 bar then bleeds
off to redline.

But recently i turned the boost down to what turboxs says to
run at 16.5 psi and my car feels faster but i have not tried this
setting at the drag strip. but why is it like this? more boost=
more hps right?

Second Q for my car if its above 60 degrees my car feels faster,
is this because when this program was made it was programed
at whatever temp it was outside? or does our car pull timing the
colder it gets?
Or cause my m2 intercooler is making too cool of intake charge?

Also i'm not the best shifter but my 60fts are always 1.8 and
have 1/2 tank of gas with 2 gals of 108 octane in the mix,
and stock tires.

But still my times should be in the lower 13s right? i don't power
shift like not using the clutch!!

If anyone has any advice i would be much apprecitated. THANKS

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[phxscooby101]

bump for me. anybody got any ideas?

[tdman77]

More boost = more power

This is wrong. You have to optimize your motor to be able to run more boost. When Mark dynoed my car we found that the highest gains were made with under 16psi of boost. There are alot of factors that you need to consider. Such as A/F ratios and timming. Unless your chip is tuned for 18psi running the higher boost could cause some serious problems. I would bet money that you were getting detonation running that higher boost without A/F correction. Try turning your boost down to around 1.15 bar and try racing again. Or even better find someone who has a G-Tech and try various boost settings and see where the most gains are made. I would put money down that you will see the best performance around 16psi or a little less.

Mor boost + corrected A/F + corrected timming = more power

[StevieD]

On some stock engines (not sure about subs) more boost could produce knock, which the ECU might retard the timing = less power.....

[gabedude]

The sweet spot on the REX seems to be around 15.5 PSI. That's what unichip owners as well as MBC'ed owners on the stock turbo are finding out. Keep it under 16. With a 1.8 60 ft you should pull mid 13's at least. I consistently pull 13.8 with just an MBC. BTW, I set my boost at around 15.5-16 PSI.

[tdman77]

Originally posted by gabedude
The sweet spot on the REX seems to be around 15.5 PSI. That's what unichip owners as well as MBC'ed owners on the stock turbo are finding out. Keep it under 16. With a 1.8 60 ft you should pull mid 13's at least. I consistently pull 13.8 with just an MBC. BTW, I set my boost at around 15.5-16 PSI.

That's exactly right. On the dyno we found the sweet spot of my car to be 15.6psi. This gave the most gains without a knock at high rpms.

[StefWRX]

Hey guys,

The "sweet spot" you are referring to is the turbo's efficiency range. Since the turbo is relatively small, it has good spool up characteristics (without the 1,000 cats) but tends to wheeze a bit up top. Consequently, turning up the boost past say 16 psi will start pushing it out of its efficiency range, meaning it has to work harder to produce the boost you want. Working harder=more heat, so you get to a point where the boost that the turbo produces is not as useful as it would be with a larger turbo. Generally speaking, the more charged air you can get into the engine at the coldest temp (more dense), the more powerful the explosion in the cylinder= more power. So for the most part, more 20 psi on an efficient turbo creates more power than the stock turbo on 16 psi. I know, this is the simple expanation, of course things like timing/fuel come into play.

Stefan
Mach V (soon to be FastWRX.com)

[phxscooby101]

I'm not getting knock according to my knocklink, but i can feel
like its just not pulling above 6000 rpm. it was odd when i got
my fastest time was when my engine was heat soaked pretty
good.

I always add 108 octane to my 91 octane gas here, also the
chip is tuned for 91 octane.

Any ideas about temps and my m2 intercooler maybe to cold
outside?

does it matter if say you have a huge intercooler and use the
turbo out of its efficency range would you still make less hp?
thanks

[phxscooby101]

Anyone else got an ideas? bump

[AZScoobie]

Originally posted by phxscooby101
Anyone else got an ideas? bump

Chad. Been there done that. I have a scan tool and I can read your advance figures if you stop by tonight or tomorrow.

On my car if I go to 15 psi I get about 17 degree's of advance in the midrange. If go to 17 psi I get about 10 degree's.. This is why people find that running 15 psi is the hot ticket. If you turn up the boost past that you will feel more trq but the reduced timing really kills the top end off. I used to think the lack of timing was due to some knock. This can be true and some of it might be..But now my research shows me that when the MAP sensor reads much over 200kpa timing is reduced and fuel is dumped. I dont have a unichip so my tests are going to be different. If my hunch is correct I could do a nasty trick and use a Zener diode to clamp the map sensor to 200kpa, but I am using Stand alone very soon so why bother.... Besides you have the unichip so you dont have to do nasty tricks like that

If you want to take the time to read your advance and adjust your boost with my scanner you can. You car is not that far off as 98mph is not to shabby.

I also use the Gtechs G meter. Its crude but effective in showing me forward G's. If I do the exact same run on the same road I can see differences in G's depending on my boost level. I dont use the Hp portion of the Gtech.. Just the G meter itself. Mainly I tune my boost level to the point where my advance level is not degraded. This has always gave me the most power.

Dont forget to reset the ECU when you change your boost levels and remember... After a reset you will need to drive the car a bit and do some WOT runs before your race. I have noticed my car runs lean and slower if I reset the ECU and make a pass.. After a few miles and some WOT pulls the power comes back. You may have to leave the strip and run up and down the highway for a bit and then come right back...

I am going to Speedworld on Wednesday if you want to go.

CT

[phxscooby101]

Azscoobie your the *****. should have just asked you . i going to
buy a palm but what program are you running for it?
p.m. me and give me your phone # i'll call you.
i think its going to rain on weds if it does i won't go of course.
if it does rain it will be a miracle i still have not drove my
in the rain HAHAHA . i've had it since july HAHAHA later chad

[AZScoobie]

Originally posted by phxscooby101
Azscoobie your the *****. should have just asked you . i going to
buy a palm but what program are you running for it?
p.m. me and give me your phone # i'll call you.
i think its going to rain on weds if it does i won't go of course.
if it does rain it will be a miracle i still have not drove my
in the rain HAHAHA . i've had it since july HAHAHA later chad

I use OBDtool and another scan tool with my laptop. I use the www.ross-tech.com cable. But I dont use his software. I hope it does not rain. I need to make a few more passes

I will PM ya my #

CT

[SPeeDSiN]

Why is he only running 14s with those mods?
Of course I have thought of driver error. Technically though,
why are they so high?

[Mario WRX]

hey there buddy.... you mentioned something about a cable .... is this the cable to read stuff from your ecu.... where can i get one ... i need a laptop right.... tell me what this software does what can i modify...??? pleae get back to me marioaias@aol.com thanks in advance