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2017 GTi PP at VIR

Mini7

Autocross Champion
Location
Charlotte, NC
Car(s)
2017 GTi Sport PP
VIR Sunrise

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Mini7

Autocross Champion
Location
Charlotte, NC
Car(s)
2017 GTi Sport PP
Guys I’ll respond as soon as I can. It’s great to be back at VIR with my homies.

Definely got something going on with the engine. I’m down on power down the straights. Need to check for boost leaks but I’m thinking it’s something else. Need to recheck waste-gate calibration. The car looses power then come back like I got kicked in the rear. Down on Vmax on the straights.
 

xXDavidCXx

Autocross Champion
Car(s)
2017 GTI SE DSG
Yes, I understand that, but swift helper vs assist springs have diffrent spring rates, I'm curious which @Mini7 is using.

I'm currently considering similar set up.
The spring in the picture is flat under body weight, it adds no rate to the overall suspension.
 

q74

Go Kart Newbie
Car(s)
R
The spring in the picture is flat under body weight, it adds no rate to the overall suspension.
Yes, I am aware that is what a helper spring is designed to do, but I found swift sells 2 diffrent types of flat springs; the traditional helper spring, and an "assist" helper spring with a higher rate. I'm curious of anyone has any thoughts or experances on the diffrences between the two.

(from swifts website - Like our helper springs, the assist springs are designed to be fully compressed at static height. Every one of our assist springs compress to the exact same height. This allows drivers to change assist springs without resetting the perch on the coilovers so the ride height isn't affected. Heavier rates of assist springs over helper springs are used to fine tune the rebound travel of the shock. These springs can also help preventing loss of traction due to inside wheel lift during hard cornering.)

https://www.swiftsprings.com/products/assist-helper-springs/
 

xXDavidCXx

Autocross Champion
Car(s)
2017 GTI SE DSG
Yes, I am aware that is what a helper spring is designed to do, but I found swift sells 2 diffrent types of flat springs; the traditional helper spring, and an "assist" helper spring with a higher rate. I'm curious of anyone has any thoughts or experances on the diffrences between the two.

(from swifts website - Like our helper springs, the assist springs are designed to be fully compressed at static height. Every one of our assist springs compress to the exact same height. This allows drivers to change assist springs without resetting the perch on the coilovers so the ride height isn't affected. Heavier rates of assist springs over helper springs are used to fine tune the rebound travel of the shock. These springs can also help preventing loss of traction due to inside wheel lift during hard cornering.)

https://www.swiftsprings.com/products/assist-helper-springs/
Ask better questions, get better answers.
 

Mini7

Autocross Champion
Location
Charlotte, NC
Car(s)
2017 GTi Sport PP
are you using a helper or assist spring?
I’m using a 3k Swift helper spring in the rear.

For the front I bought a 4K Assist spring. Both compress under static weight.
The helper spring fully collapsed height is 27mm if I recall correctly. Double check on the Swift site to make sure I’m right. Factor in another 5mm for the connector and thrust sheets.

The compressed height for the assist spring is a little more.

The rear appears to be a little more compliant and comfortable than before. Maybe comfortable is the better description. May be a placebo effect after having installed it.
 
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Mini7

Autocross Champion
Location
Charlotte, NC
Car(s)
2017 GTi Sport PP
Great to hear the cooling mods helped. Today was unusually warm, so good day to test it out.
As far as the boost flutter issue, is it happening at a specific RPM or the entire range. I’ve seen boost flutter issues when there’s a lean condition on the top end. Any way to run logs on track?
So I don’t have any way to record data. I’m on an APR high torque tune for my IS38 tuned for 91 Octane.
Not sure if a Cobb will record data when the ECU is programmed by another brand tune?

Boost flutter was in 4th gear 5-6,000rpm. Struggling up the hill on the back straight. I still need to check my Harry’s data but I’m down on straight line speed. Had the same issue down the front straight and heading into the esses.

Everything felt good. Car handled well. Highest ambient was 86F with oil temp max of 252F. I cannot confirm coolant temps because of the POS coolant placebo gauge.

So I have:
Lean AFR at the top end at WOT
Running hot and dumping fuel to cool ( don’t think this is an issue for me now)

I figured I’d get a code if I had a boost leak and I didn’t hear any leaks.
I will recheck wastegate calibration. That’s the only other thing I can think of. Not sure if that would cause a boost flutter.

I’m at 91k and haven’t cleaned my intake as yet.
 

Ronnie_B

Go Kart Champion
Location
United States
So I don’t have any way to record data. I’m on an APR high torque tune for my IS38 tuned for 91 Octane.
Not sure if a Cobb will record data when the ECU is programmed by another brand tune?

Boost flutter was in 4th gear 5-6,000rpm. Struggling up the hill on the back straight. I still need to check my Harry’s data but I’m down on straight line speed. Had the same issue down the front straight and heading into the esses.

Everything felt good. Car handled well. Highest ambient was 86F with oil temp max of 252F. I cannot confirm coolant temps because of the POS coolant placebo gauge.

So I have:
Lean AFR at the top end at WOT
Running hot and dumping fuel to cool ( don’t think this is an issue for me now)

I figured I’d get a code if I had a boost leak and I didn’t hear any leaks.
I will recheck wastegate calibration. That’s the only other thing I can think of. Not sure if that would cause a boost flutter.

I’m at 91k and haven’t cleaned my intake as yet.
You’re running into all the same issues I had when I ran my APR k04 tune earlier this year. I was running lean on the top end, the ECU would compensate by pulling boost, and the boost would flutter. To add to that, the engine made a ton of heat due to lean condition. Made for several miserable track events. I eventually switched over to a Protune and now data log all my sessions which takes the guesswork out of it. I’m currently running less boost than the APR tune, but higher final timing (~15 degrees at redline) and my AFRs are in the 11.75 range through the RPM band. The other variable is injector timing, which gives a good indication of when the stock system is reaching its fueling limits.
 

Mini7

Autocross Champion
Location
Charlotte, NC
Car(s)
2017 GTi Sport PP
Not the news I wanted to hear. Hoping that the injectors have the headroom to run an IS38 without getting into high duty cycle percentages.
 

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
Not the news I wanted to hear. Hoping that the injectors have the headroom to run an IS38 without getting into high duty cycle percentages.
I must have missed a prior post of yours. I normally run a TPC20 hybrid that produces 416 HP and 428 torque and I've never not had enough fuel with the stock injectors. I do have a HPFP but I was told that it wasn't mandatory.
 

GTIfan99

Autocross Champion
Location
FL
I must have missed a prior post of yours. I normally run a TPC20 hybrid that produces 416 HP and 428 torque and I've never not had enough fuel with the stock injectors. I do have a HPFP but I was told that it wasn't mandatory.

Not mandatory, but you risk fueling issues without it, from what I understand.

It's like tuning your car and not upgrading the IC. It's not required, but you're asking for issues.
 

Mini7

Autocross Champion
Location
Charlotte, NC
Car(s)
2017 GTi Sport PP
I must have missed a prior post of yours. I normally run a TPC20 hybrid that produces 416 HP and 428 torque and I've never not had enough fuel with the stock injectors. I do have a HPFP but I was told that it wasn't mandatory.
I was responding to @Ronnie_B post that injector duty cycle/fueling headroom had gotten marginal on his K04 upgrade on his Mk6. And that I may be running into similar issues with the boost flutter I was experiencing at VIR with my APR tuned IS38.
 

Mini7

Autocross Champion
Location
Charlotte, NC
Car(s)
2017 GTi Sport PP
On another note. Im happy with the performance of the APR CC. Only got 50ml of fluid out after the end of the weekend. One of the hoses was a little short and I had to use my Racing Line hose. As soon as I get that rectified I’ll have my RL up for sale.

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