N75 or wastegate

[h100vw]

tried flipping my N75J after reading through some real old uk forums... so the long tip was not into the TIP, but towards the WG... which is not how 95% of people install it.. Gained 5psi. boost is a tiny bit jerky in 2nd, first pulls pretty hard.

Still doesnt run to tune spec, or how it feels when bypassing the n75.

Catching up with BFLAT later to try out his n75 and see what happens with that.

They need to be plumbed in correctly. So watch that with you suddenly finding 5PSI.

Gavin

[noone]

From memory the race is installed what looks like backwards, the length of the barbs should help show orientation. Make sure you're not installing the spare backwards.

They do install backwards (or what looks like). If you've been missing boost, the ECU may have to do a little recalibration. Could be 1/2 the problem with a leak or VAC issue. Think the MkIV's have vac lines / recirc lines that are prone to splitting.

[Lito]

They do install backwards (or what looks like). If you've been missing boost, the ECU may have to do a little recalibration. Could be 1/2 the problem with a leak or VAC issue. Think the MkIV's have vac lines / recirc lines that are prone to splitting.

all n75s instal the same way, long nipple to TIP, opposite nipple to Wastegate and middle nipple to charge pipe. The electrical connector will point different ways depending on what N75 you have. IMO you should use the OEM valve, it's what the tune was written for, I think E is the latest revision for the 1.8t.

[leighaus]

bought an MBC. Installed it with the N75J only electrically connected and the TIP hole plugged.

Was pulling 19 PSI fine for a bit (a bit jerky here n there on partial throttle, but to be expected)... Then i went for a second drive just to enjoy the power and was getting complete boost cut at 17psi, the car makes like a pop and complete loss of power. Did some searching and found it to be somewhat common, whereby theres a limp at 17psi... with likely issues being coilpacks breaking down, dodgey MAF and some reporting that doing the diode mod can fix it.

i wound the boost back to 16psi on the MBC for now and suffer no issues. The car never used to hold boost and does through the rev range for a lot longer now, which is great.

The car is tuned for 21peak19hold, so i'd like to get those few extra ponies once i diagnose the issue.

[Bug_racer]

bought an MBC. Installed it with the N75J only electrically connected and the TIP hole plugged.

Was pulling 19 PSI fine for a bit (a bit jerky here n there on partial throttle, but to be expected)... Then i went for a second drive just to enjoy the power and was getting complete boost cut at 17psi, the car makes like a pop and complete loss of power. Did some searching and found it to be somewhat common, whereby theres a limp at 17psi... with likely issues being coilpacks breaking down, dodgey MAF and some reporting that doing the diode mod can fix it.

i wound the boost back to 16psi on the MBC for now and suffer no issues. The car never used to hold boost and does through the rev range for a lot longer now, which is great.

The car is tuned for 21peak19hold, so i'd like to get those few extra ponies once i diagnose the issue.

21 psi with a ko3 isnt possible , 19 psi hold even more so !
Most tuners run around 16-17 psi with the AGU engine .

[leighaus]

hmm.. maybe my tuner doesnt know his arse from his elbow and got confused... im guessing im hitting the cut from the tune then.. ill leave it as is with the MBC as it runs quite nicely. I fully disconnected the N75 and got no CEL or limp and its even running a bit smoother.

So im pretty happy knowing that bug racer. cheers.

[leighaus]

After running a mbc for ages on 15psi ( any higher caused spikes and boost cut) I got super sick of the surging and part throttle issues.. ordered a vanilla n75 from ecs. Installed it ...... Back to 9 psi.. I want expecting that. Given I thought the n75j was incompatible and my old n75 had died..

More investigating required i guess... unplugging the new N75 with it all still plumbed still yields 5.5ish psi.

[leighaus]

after reading this : Golf not making full boost

im starting to think maybe i have a bad tune?

[h100vw]

after reading this : Golf not making full boost

im starting to think maybe i have a bad tune?

Adjust the actuator up so it makes a touch over 6PSI and see what happens. Assuming that you are convinced that there's no boost leaks at all.

I am doubting the tune is your problem. Software can't change over time, inputs and hardware may.

Gavin

[leighaus]

The tune has never worked with an n75 running, only an mbc which in a way is only a manual boost request. Not ecu based.
If I can hold 15psi with an mbc I don't have a spongey wg or boost leak .

I'll try increase the wg as suggested

[h100vw]

The tune has never worked with an n75 running, only an mbc which in a way is only a manual boost request. Not ecu based.
If I can hold 15psi with an mbc I don't have a spongey wg or boost leak .

I'll try increase the wg as suggested

Don't go silly, 2 turns will be plenty.

Gavin

[leighaus]

Made 0 difference gav.... The front nut is only may 3-4 threads from the end of the thread in the wg end.

[h100vw]

So you effectively shortened the rod, correct? Wound the nut closest to the canister closer first. Then the one on the end to lock it up again.

There's no way if you did this, there'd be no change. I can't think of an explanation why that would be. it doesn't make sense to me.

gavin

[Bug_racer]

The tune has never worked with an n75 running, only an mbc which in a way is only a manual boost request. Not ecu based.
If I can hold 15psi with an mbc I don't have a spongey wg or boost leak .

I'll try increase the wg as suggested

Do you even have a tune ?

You can raise the boost to the turbo limits with a MBC .
Only issue is as you raise it the ECU throws more fuel in .

[leighaus]

So you effectively shortened the rod, correct? Wound the nut closest to the canister closer first. Then the one on the end to lock it up again.

There's no way if you did this, there'd be no change. I can't think of an explanation why that would be. it doesn't make sense to me.

gavin

yes gav, essentially shortened the rod, which in turn starts to open the exhaust valve.

Makes no sense to me either.. I might contact the tuner... bit of a pain in the arse tho (long story).

Do you even have a tune ?

You can raise the boost to the turbo limits with a MBC .
Only issue is as you raise it the ECU throws more fuel in .

yes, Viezu tune. approx 12 months ago (current owner).