GOLFMK8
GOLFMK7
GOLFMK6
GOLFMKV

IS38 JB4 only vs full stage 2

G

Gatucar

New member
Location
Mexico
Hi all,

I have a GTI MK7 and the power is not fabulous. This quickly changed with the addition of a JB4. I was thinking on the best way to add more power on top of the JB4 and I have an idea that is not well supported/commented on the forums, thus I decided to look for some experience in the forum.
For a FWD I am happy with the power in 1st and 2nd gear but not satisfied with the 3rd gear. TO fix this I am planning on a simple set up. Just go for the larger IS38 turbo and call it a day. No intercooler, no extra software, no DP. I know that there will be a lot left on the table power wise. But the turbo upgrade ($ 1300) makes more financial sense to me compared to a true stage 2…Shouldn’t this setup outperform a stage 2 by a large amount (for more or less the same $$$). Sure, I may have some heat soak problem after some WOT time but I do not anticipate doing a lot of pulls…Just one or two every now and then…

I would not like to get a very expensive set up for some reasons. 1) FWD has problems putting the power down 2) If too expensive I prefer to get a Golf R and JB4 that instead for a little rocket in your pocket and call it a day.

Suggestions are appreciated.

Gatucar.
 
R

r-gazmic

Passed Driver's Ed
Location
Colorado Springs
If you're already unhappy about how FWD cars put power down, I wouldn't spend any money on the GTI and just save up to trade in on an R.


And I seriously doubt you'd outperform a legit stage 2 setup by a large margin with just an IS38 and a JB4. You're gonna heatsoak immediately pumping an IS38 through a stock GTI intercooler.
 
Hoon

Hoon

Autocross Champion
Location
Rhode Island
That sounds like a setup that would be embarrassed by a healthy stage 2 car.

Spending $1300 on a turbo, leaving the exhaust corked up and pumping hot air into the engine is not a recipe for killer power. APR rates their stock DP IS38 tune (which I think requires an IC) as 27hp above their stage 2, but 28ft-lbs below the stage 2.

Managing it solely with a JB4 also has limitations, so you're not likely to see APR numbers.

I don't know exactly what to expect for power, but my assumption is it would be well within the range of a stage 2 car. You could do a DP for $2-400, IC for $300, and a real tune for $6-800.

As for the traction thing, first and second will always be useless with high power levels, but with a maxed IS38 on E30 im usually dead hooked in 3rd...you do have to invest in a good wheel/tire setup though.
 
G

Gatucar

New member
Location
Mexico
Hoon, r-gazmic
Thanks for your comments.
I am just exploring these options and I have a lots of doubts and that is why I am reaching out to people with more experience.

That being said, has anyone actually seen my proposed setup? I think the ECS guys cite this as a possibility...buy marketing people from all companies will bend a little the facts to push their products.

The other thing that makes me unsure about the updated DP with the stock turbo is the amount of turbo failure reported close after the DP is installed...maybe IS38 only could be more reliable?

Thanks again
 
R

r-gazmic

Passed Driver's Ed
Location
Colorado Springs
If anything I'd think the aftermarket DP would make the turbo last longer. Less backpressure so the turbo isn't working as hard to get air through.


Now, when people put on a DP they also tune the car typically, that may be the cause of any increase in failure you notice. You don't tune a car and then drive it like a grandma, you're going to go WOT more than you did stock, that might wear the turbo out sooner.



There's also been turbo failures on totally stock cars, so it could all just be luck of the draw. A "good" is20 or is38 will last even when tuned, a "bad" one will break regardless of what you do with it.


You just need to think about what your goal is for the car, and then figure out what hardware/tuning you need to get there. If your goal is more grunt than the JB4 is currently giving you, my first step would probably be posting the map/settings you're using on the JB4. Maybe someone more experienced with that tool can point out some tweaks to make that get you what you want without any hardware at all. I've never used one but I understand there's quite a bit of logging/tweaking to be done to get the most out of it.
 
Hoon

Hoon

Autocross Champion
Location
Rhode Island
r-gazmic said:
If anything I'd think the aftermarket DP would make the turbo last longer. Less backpressure so the turbo isn't working as hard to get air through.


Now, when people put on a DP they also tune the car typically, that may be the cause of any increase in failure you notice. You don't tune a car and then drive it like a grandma, you're going to go WOT more than you did stock, that might wear the turbo out sooner.



There's also been turbo failures on totally stock cars, so it could all just be luck of the draw. A "good" is20 or is38 will last even when tuned, a "bad" one will break regardless of what you do with it.


You just need to think about what your goal is for the car, and then figure out what hardware/tuning you need to get there. If your goal is more grunt than the JB4 is currently giving you, my first step would probably be posting the map/settings you're using on the JB4. Maybe someone more experienced with that tool can point out some tweaks to make that get you what you want without any hardware at all. I've never used one but I understand there's quite a bit of logging/tweaking to be done to get the most out of it.
Click to expand...

Completely agree.

A reduction in backpressure is an increase in efficiency, meaning the turbo can make the same power with less stress. People always add a tune with a DP, greatly increasing boost and therefore stress on the turbo.

You could run an IS38 at lower boost than an IS20 to make the same power, which may help with reliability, but you're then sacrificing spool time and boost threshold without the redeeming qualities of higher power output.

Whatever you decide, a good IC should be on the list.

This decision starts with a power goal. How much WHP do you want to make?
 
G

Gatucar

New member
Location
Mexico
Great discussion guys. I a m now tempted to get a DP! However, in my complete ignorance I am tempted to think that having more back pressure will cancel the differences in pressure before and after the turbo turbine which should translate into LESS movement and thus less turbo stress. I am inclined to think that the less the turbo rotates the less stress is applied into the rotating parts, preserving the component... ??? From my perspective the DP relates with turbo failure because there is just more movement derived from the high pre turbine and low post turbine pressure. I am not trying to be a pain just trying to understand some concepts to make an informed decision.

I will do as you suggest and start fine tuning the JB4.
My target HP is around 300. With JB4 I should be around 250 give it or take. I need 50 extra ponies.

Thanks
 
TheGreekFreak

TheGreekFreak

Go Kart Champion
Location
MA
For 300hp, I wouldn't even consider a turbo swap. IC, DP, tune, and call it a day. All in, it can be cheaper than the turbo itself and you'll be in the 310whp range from a good tuner.

Sell the JB4 and you'll recoup some funds to work with. No point fiddling around with an OEM DP, no IC, and an IS38 on a JB4 only imo.
 
Rafiki76

Rafiki76

Ready to race!
Location
Los Angeles
Car(s)
MKVII GTI
TheGreekFreak said:
For 300hp, I wouldn't even consider a turbo swap. IC, DP, tune, and call it a day. All in, it can be cheaper than the turbo itself and you'll be in the 310whp range from a good tuner.

Sell the JB4 and you'll recoup some funds to work with. No point fiddling around with an OEM DP, no IC, and an IS38 on a JB4 only imo.
Click to expand...

APR Stage 2 with just a DP the flash, and recommended you get an intercooler is cheaper than an IS38 and you'll have over 300 hp and almost 400 lb-ft.
 
Hoon

Hoon

Autocross Champion
Location
Rhode Island
Gatucar said:
Great discussion guys. I a m now tempted to get a DP! However, in my complete ignorance I am tempted to think that having more back pressure will cancel the differences in pressure before and after the turbo turbine which should translate into LESS movement and thus less turbo stress. I am inclined to think that the less the turbo rotates the less stress is applied into the rotating parts, preserving the component... ??? From my perspective the DP relates with turbo failure because there is just more movement derived from the high pre turbine and low post turbine pressure. I am not trying to be a pain just trying to understand some concepts to make an informed decision.

I will do as you suggest and start fine tuning the JB4.
My target HP is around 300. With JB4 I should be around 250 give it or take. I need 50 extra ponies.

Thanks
Click to expand...

You're not factoring the wastegate in. To overcome the additional backpressure, the ECU is going to force more air through the turbo to hit the targeted torque. You have to push the turbo harder to move the same air mass when you add restrictions.

A turbo swap for 300whp is crazy IMO. You look at an MK7 the wrong way and it'll make 300whp.

I went from 216whp stock to 303whp with a few worthless intake mods, Uni S2 tune, and eBay DP. Peak boost was only about 21.5psi depending on environmentals.

Swapped the turbo at 28K miles (26K tuned) and it is in very close to new condition. Zero in/out play, a tiny amount more side/side than a new turbo. Would have lasted a very long time on that setup.

Unitronic, APR, Cobb and Eurodyne all provide tunes and/or tuning platforms to easily accomplish this. It is possible (but more difficult) with JB4.

TheGreekFreak said:
For 300hp, I wouldn't even consider a turbo swap. IC, DP, tune, and call it a day. All in, it can be cheaper than the turbo itself and you'll be in the 310whp range from a good tuner.

Sell the JB4 and you'll recoup some funds to work with. No point fiddling around with an OEM DP, no IC, and an IS38 on a JB4 only imo.
Click to expand...

This.
 
Last edited:
mk7rip

mk7rip

Go Kart Newbie
Location
socal
Car(s)
mk7
I believe there was a member here who was running an is38 swap with pretty good results on only a jb4. Can't remember if he was 2.0 or 1.8 though
 
crxgator

crxgator

Autocross Champion
Location
Raleigh, NC
Car(s)
All the MQBs
Think of an IS38 swapped GTI with a JB4 the same as a Golf R with just JB4. The downpipe isn’t going to hurt the turbo. It’ll be fine.


Sent from my iPhone using Tapatalk
 
You must log in or register to reply here.
Top