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IS38 1.8T Info/Discussion

Blade3562

Go Kart Champion
Location
Middletown, PA
Well I found the main contributor to my original 1.8 letting go. The hiccup that plagued my original motor still existed after swapping the new motor and occurred with either 1.8 HPFP. The last time my car ran well was at Pocono in 2018. When you run the North Course at Pocono you are in a long right hander for almost half the track. One of the sessions my fuel level dipped below 1/2 tank which starved the LPFP of fuel long enough to damage it. The damaged LPFP caused a lean mixture at high RPMs.

Yesterday I installed an APR HPFP and LPFP, and the problem was totally gone! Pulled like a freight train all the way to 7500rpm in first through fourth. Case closed. Man this car is fun, I can't wait to get a little more seat time! A proper dyno tune and it'll be a freaking rocket.
 

ZuMBLe

Autocross Newbie
Location
NY
Car(s)
Alltrack 6MT
Well I found the main contributor to my original 1.8 letting go. The hiccup that plagued my original motor still existed after swapping the new motor and occurred with either 1.8 HPFP. The last time my car ran well was at Pocono in 2018. When you run the North Course at Pocono you are in a long right hander for almost half the track. One of the sessions my fuel level dipped below 1/2 tank which starved the LPFP of fuel long enough to damage it. The damaged LPFP caused a lean mixture at high RPMs.

Yesterday I installed an APR HPFP and LPFP, and the problem was totally gone! Pulled like a freight train all the way to 7500rpm in first through fourth. Case closed. Man this car is fun, I can't wait to get a little more seat time! A proper dyno tune and it'll be a freaking rocket.
Still have a 1.8 in there? If yes, what tune?
 

Blade3562

Go Kart Champion
Location
Middletown, PA
Still have a 1.8 in there? If yes, what tune?
Still a 1.8! It's currently APR tuned, but will be switching to United Motorsport once they have the time to get me in. I'll take the car up to them in CT and drop it off for them to develop software for FWD 1.8s.

For what it's worth the car is running great with the APR file and pumps. Currently no CELs and it idles great!
 

Ironshade

Go Kart Newbie
Location
Atlanta Ga
Well I found the main contributor to my original 1.8 letting go. The hiccup that plagued my original motor still existed after swapping the new motor and occurred with either 1.8 HPFP. The last time my car ran well was at Pocono in 2018. When you run the North Course at Pocono you are in a long right hander for almost half the track. One of the sessions my fuel level dipped below 1/2 tank which starved the LPFP of fuel long enough to damage it. The damaged LPFP caused a lean mixture at high RPMs.

Yesterday I installed an APR HPFP and LPFP, and the problem was totally gone! Pulled like a freight train all the way to 7500rpm in first through fourth. Case closed. Man this car is fun, I can't wait to get a little more seat time! A proper dyno tune and it'll be a freaking rocket.
No issues running upgraded pumps? Also 7500? I run apris38 and cant get more than 7200rpm.
 

ZuMBLe

Autocross Newbie
Location
NY
Car(s)
Alltrack 6MT
Still a 1.8! It's currently APR tuned, but will be switching to United Motorsport once they have the time to get me in. I'll take the car up to them in CT and drop it off for them to develop software for FWD 1.8s.

For what it's worth the car is running great with the APR file and pumps. Currently no CELs and it idles great!
Do you have any way to log a pull with your current setup? Are you aware of any reason why the APR pumps seem to work without specific tuning?? That pump is $$$ though.
 

Faceman

Drag Racing Champion
Location
Long Island
Car(s)
'17 GSW 4Motion
For what it's worth the car is running great with the APR file and pumps. Currently no CELs and it idles great!
You will probably be fine till the ambient temperatures drop.
 

joedubs

Passed Driver's Ed
Pulled like a freight train all the way to 7500rpm in first through fourth. Case closed.
Damn... I need to grow some balls.

7500rpm? What's the factory valve train actually rated for?

The chart in the self study program ends at 6500rpm, and the redline has that first mark at 6500, but both of those are likely due to the fact that the stock turbo isn't rated to go any further than that.
 

Blade3562

Go Kart Champion
Location
Middletown, PA
Put 774 miles on the car this weekend, just under 1000 total on the fuel pumps. I threw a CEL around 300 miles into my trip. The CEL was for low voltage and every module had this error. As soon as I saw the code I remembered I forgot to fully tighten the positive wire on the back of the alternator. Easy fix! No CELs related to the fuel pumps yet, but as stated above it seems to be a cold weather cold start issue. It definitely runs super rich at idle. Car pulls like a freight train, but needs a proper tune to unlock its full potential.

7500rpms is just my stress test, if everything works and holds together I don't have to worry about a minor overrun at a track day. After some testing 6800-7000 seems like the sweet spot for shifting the 5 speed. I really need to go to an airport mile event to test shift points; the 1/4 mile is too short. Stock valve springs are the only worry with high revving, but I do not recall their rpm rating.
 

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
Put 774 miles on the car this weekend, just under 1000 total on the fuel pumps. I threw a CEL around 300 miles into my trip. The CEL was for low voltage and every module had this error. As soon as I saw the code I remembered I forgot to fully tighten the positive wire on the back of the alternator. Easy fix! No CELs related to the fuel pumps yet, but as stated above it seems to be a cold weather cold start issue. It definitely runs super rich at idle. Car pulls like a freight train, but needs a proper tune to unlock its full potential.

7500rpms is just my stress test, if everything works and holds together I don't have to worry about a minor overrun at a track day. After some testing 6800-7000 seems like the sweet spot for shifting the 5 speed. I really need to go to an airport mile event to test shift points; the 1/4 mile is too short. Stock valve springs are the only worry with high revving, but I do not recall their rpm rating.
I hope one of these times you perform your 7500 RPM stress test it doesn't fail.
 
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