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Don't buy an IS38...but should I?

jimlloyd40

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
doug@frankenturbo.com said:
Jim -- we've been discussing the fueling system's limits quite a bit in our FB Group. Assuming the Gen3 TSI engine will develop over 400whp on pump gas without knock, you feel the Mk7's fuel pumps can deliver that amount of fuel flow? Again, on just gasoline.
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That's what I've read numerous times in the forum and I'm approaching 400 HP and it's fine so far.
 
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greggles

Drag Race Newbie
Location
usa
Car(s)
GTI
Doug,
Is it possible to get your turbo with just the actuator optimized? (If we don't need the DV or inlet pipe)
 
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billbadass

Drag Racing Champion
Location
your moms house
roystr said:
@billbadass -- Thanks for chiming in. I watched the install saga unfold with your L380. My impression was that on pump gas, you weren't overly satisfied with it and felt that the torque was unexplainably low? On Ed's dyno, most IS20/IS38 turbos are in the 400-420 wtq range. I totally get the "wanting more" though...smarter up front to make a "future proof" decision. I like the Vortex (a lot) but LPFP + MPI seems to be "the way" now? Awhile back Ed said that to run the EQT, all you need (besides the turbo itself) was the HPFP upgrade (which to me seems a shit ton easier AND cheaper than the LPFP + MPI conversion).

$ per HP though the IS38 is still the clear winner (if your goal is 380-400 whp). If your goal is 500 whp, obviously the IS38 can't compete.
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the is38 dynos you will see have this torque spike around 3k rpm that makes the torque look higher than it actually is. I'm not unhappy with this L380x turbo, but it has the slower response of an EQT turbo but it doesn't have the 550whp potential so if I was doing it again I'd just do an EQT. The L380x was maybe 15lbs of mid range lower on the torque than I expected also, but on the street I don't ever think it's lacking in torque and I drive it on E50 full time.

I think if you did just an EQT and just put HPFP only in it you would be super happy. you don't need to spin the EQT turbo to its max to be super happy with how the car is, and my own personal opinion is that an EQT turbo will be more reliable than an is38 anyway. I believe Ed has done plenty of EQT turbo installs that did not have MPI + LPFP so I think those are only necessary if you want to push big power or want stronger ethanol blends.

I personally have found over all my "built" cars that the less you can change and the more simple you can keep it the more reliable the car will be, so I personally just wanted to stick with HPFP only to keep it as simple and cheap and reliable as possible, and it's nice my car looks totally stock under the hood to the untrained eye if I put the stock intake on

on p4s michelin tires my car puts down 468whp easily on the street also and that is with an open differential. Ed's COBB traction control is amazing also. I don't think 3rd gear would hook up with too much more power but 468whp hooks up third great, and 1st/2nd COBB traction control keeps it very well controlled. I've actually been super surprised how smooth, controllable and easily this chassis took this power level and I'm on stock suspension
 
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billbadass

Drag Racing Champion
Location
your moms house
if you're making this decision and considering NOT doing one of the hybrids because of lag or whatever, you should try and track down a local car with a hybrid and go for a ride in it. the slightly slower response of an EQT or Hybrid vs is38 is meaningless on the street and almost can't even really feel it, and the higher rpm charge of these hybrids is intoxicating and well worth 300-400rpm slower spool at rpm you never race at anyway
 
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billbadass

Drag Racing Champion
Location
your moms house
jimlloyd40 said:
Just curious but why not the Littco L450?
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I think the EQT turbo is the fastest spooling turbo with that power potential in that price range, and I'd always rather buy something local if possible in case of trouble shooting since UK is just a long way away, and Ed customer service is incredible and he is a jedi tuner. a good COBB pro tune is just light years better than some random Off the shelf tune and you can resell the COBB later anyway so I don't know why anyone at this point today would ever use an APR tune or whatever if they are anything more than stage2
 
jimlloyd40

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
billbadass said:
I think the EQT turbo is the fastest spooling turbo with that power potential in that price range, and I'd always rather buy something local if possible in case of trouble shooting since UK is just a long way away, and Ed customer service is incredible and he is a jedi tuner. a good COBB pro tune is just light years better than some random Off the shelf tune and you can resell the COBB later anyway so I don't know why anyone at this point today would ever use an APR tune or whatever if they are anything more than stage2
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Amen to that.
 
A

AlienSP

Ready to race!
Location
Austin, TX
I just passed my OBD state inspection again using the Cobb stock file, from a custom EQT Stg2. Met all readiness except Fuel Sys.
My question: For those that switched to IS38 and using an upgraded HPFP, what stock AP file are you using for inspection? Don't you need a custom tune for the HPFP to operate properly?
 
Twist1

Twist1

Autocross Newbie
Location
Breaking Mustang Hearts
Go to my vs channel and see what an is38 can do with a little bit of corn juice and wr.

What others said about being the best balance is probably right. FWD sucks and we aren't hondas that make stupid power banging off the limiter for 3 gears straight. However I will say that spool was a huge concern on this platform that really isn't that bad in real life. Being in big turbo cars on ethanol honestly you really don't notice it because no one is doing pulls from 2800 rpm anyway..
 
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