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K03 flash behavior not ideal at the track

bostonaudi

Go Kart Champion
Location
Charleston, SC
Car(s)
1995 BMW M3
So, the way a typical K03 flash behaves has me more convinced the vendors are geared towards bragging rights rather than making a product that does something useful.

The way most available flashes behave is to boost the crap out of the midrange, with a big tail off at around 5k. This results in a very peaky engine, with a torque curve that looks like an amplified diesel curve on steroids. It also causes a large boost slam when the engine is pounded with 22 lb of boost at very low rpm, putting stress on engine mounts, rods, clutch, CV joints, boost hoses etc.

This is exactly what you don't want at an autocross or the track. It results in excessive wheelspin, and totally non-linear unpredictable engine response. I also think it doesn't do your little turbo any favors when its asked to be boosted at double the stock amount for 30 min at a time. I've run autocross with flashed K03's, and to be honest I think you're better off stock.

I'm not singling out any vendor as they all do it.

I happen to use Revo, and have reverted to running my engine with a custom setting of 2-0-0 on the SPS+ to more or less provide a little extra boost with a more stock like response. I almost never use the full 6-4-9 anymore. At 2-0-0 the engine peaks at 15-16 psi and works well at the track. It doesn't pull quite the same as the full performance setting but it goes just as fast 99% of the time.

I want to put a K04 in, but I don't want an even more ridiculous midrange torque slam. I'd love to see a vendor offer a more factory like even torque curve that would be more appropriate for auto-x or track use. If I do install K04 I guess I'll be experimenting again with a 2-0-0 like setting to keep it a bit more even across the midrange and still have the higher rpm hp gain.
 

bostonaudi

Go Kart Champion
Location
Charleston, SC
Car(s)
1995 BMW M3
For me all that torque just made my tires spin. I didn't have an LSD at the time either. If you have to feather the throttle a lot to control wheelspin, you might as well be stock.

I think the best way to make more power, is free up breathing first, then go with bigger turbo (which also frees up breathing) to help keep a more even powerband. Boosting the snot out a little turbo so its peaky as hell isn't my cup of tea anymore.
 

miamirice

Ready to race!
Location
Miami
The mkv is my daily so I don't know the answer to this question- isn't there shops that will customize the software to your car and the mods u have and what you want to achieve? I live in Miami and I did this with my e36 m3.
 

t.c. gtimkv

Steath mode
Location
Ft. Lauderdale
Car(s)
07 UG MKV 4door
I think you need better tires.
 

Dynjo

Ready to race!
Location
Chicagoland
The ability to raise torque at high revs is limited by the small turbo. Therefore, the "stage 1" type chips always show more gains in the midrange compared to high end. This gives you that peaky torque curve that can be annoying when trying to control wheelspin.

I am sure the vendors would love to provide more high-end torque (i.e. more horsepower and flatter torque curve) because THAT would be the ultimate bragging right, but they are limited by the hardware.
 
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StreetSpeed2000

Passed Driver's Ed
I wish APR would offer some sort of upgrade to whatever they do to their race cars. Those things live their life in the higher RPMs, so I'm sure they've tuned it for the best performance in that range.
 

bostonaudi

Go Kart Champion
Location
Charleston, SC
Car(s)
1995 BMW M3
I wish APR would offer some sort of upgrade to whatever they do to their race cars. Those things live their life in the higher RPMs, so I'm sure they've tuned it for the best performance in that range.

Yes! APR - Revo - listening?
 

John/Cue\Publik

Speed>stance
Location
Lake Stevens, WA
Car(s)
2007 Rabbit
heh sounds like you might be interested in boosting a 2.5 based on what you want out of your motor. Super flat torque curve, very manageable fat low end with insanity setting in at 3200rpm with little to no drop off to redline. Extremely smooth and predicable. Only problem is getting put in SM class. Should have some new dyno graphs up in a few weeks just gotta break in my new clutch and trans. This graph is from a few years ago and I was battling timing pull issues due to heat soak and a dirty MAF.

I've since put down better numbers but don't have access to the graphs, this is like the week after the initial turbo build and I've put a lot of effort into perfecting everything since. obviously the power curve on this shows tuning and sensor issues. This was on the first version of the c2 turbo tune which has since been significantly improved.
 

BlackVR

Autocross Champion
Location
Minnesota
Car(s)
2006 GTI
I wish APR would offer some sort of upgrade to whatever they do to their race cars. Those things live their life in the higher RPMs, so I'm sure they've tuned it for the best performance in that range.
APR doesn't even touch the boost on their race cars. I was speaking to one of their guys at NGP Racing's barbecue a while back. He said they can't touch boost in their class. He said the engines are essentially stock with the timing changed just a bit.
 

bostonaudi

Go Kart Champion
Location
Charleston, SC
Car(s)
1995 BMW M3
heh sounds like you might be interested in boosting a 2.5 based on what you want out of your motor. Super flat torque curve, very manageable fat low end with insanity setting in at 3200rpm with little to no drop off to redline. Extremely smooth and predicable. Only problem is getting put in SM class. Should have some new dyno graphs up in a few weeks just gotta break in my new clutch and trans. This graph is from a few years ago and I was battling timing pull issues due to heat soak and a dirty MAF.

I've since put down better numbers but don't have access to the graphs, this is like the week after the initial turbo build and I've put a lot of effort into perfecting everything since. obviously the power curve on this shows tuning and sensor issues. This was on the first version of the c2 turbo tune which has since been significantly improved.

Looks good, reminds me of power levels from my 944T, and it has a 2.5 liter too, but its a huge 4 banger.

I considered picking up a 2 dr 2.5 Rabbit as a track car a while ago, might have to reconsider. All the go fast suspension bits from my GTI would bolt in and the car would be a bit lighter.

Was this a kit or did you piece it together yourself?
 

Dynjo

Ready to race!
Location
Chicagoland
The 2.5 is cool, but not really what I would call flat. Now HERE is a flat torque curve.



Taken from my Volvo brochure. The engine is also a 2.5L 5-cylinder.

The flatness is artificially created by the engine calibration engineers for a variety of reasons.

The easiest way to create a flat torque curve is to lower the peak(s). That is not what most of us hot-rodders want to do. We usually want to raise torque as high as possible wherever possible, and you end up with something that looks more like Mt Everest than Nebraska.
 
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bostonaudi

Go Kart Champion
Location
Charleston, SC
Car(s)
1995 BMW M3
This thread should read as a huge rationalization on my part to get a K04. I think that and some tweaking with the SPS+ could yield what I'm looking for.

I drove a Cayman S recently, that engine feels slow initially, but you look down at the speedometer and all of a sudden you're over 100. Its a great motor, climbs nicely towards redline, not peaky, but comes on cam strongly, and great flat 6 sounds!

Porsche just announced Cayman R, time to cash out some 401k.
 
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