35i intercooler and remap.. wow

N

Nick9one1

Member
Newark, Nottinghamshire
One of the first things I did to the Z4 was replace the front cats with stainless downpipes. I followed this with a stage 1+ MHD remap and i was impressed with the results. The car felt quicker and sounded a lot nicer!

I decided to push the boat out a little by fitting a stepped intercooler, and followed it up with a 98ron stage 2+ remap

I was expecting less of a difference than I noticed between stock and stage 1+, but wow I was wrong!
The car seems transformed - I get 5th gear wheelspin if not careful!

I easily pulled away from a new a golf type R yesterday - I'd once tried this when stock and they stayed with me pretty much neck and neck.

Stock vs stepped intercooler.
IMG_8423_1024x765.JPG
 
Dammit, this is making me want to do downpipes too!
Where did you go for the intercooler? I presume there was a bit more turbo lag before the ecu adjusted itself?
 
intercooler and downpipes were both from China. Both really nice quality, as good as anything I've seen triple the price.

Intercooler was very easy to fit, taking about 1/2 an hour. The factory pipes clip straight in like they do on the stock intercooler.

Down pipes were a lot more difficult. Again the fit/build quality was great, but access is very tight under the car.
Also, either on the 335 or LHD drive cars (not sure which), the flange is turned 90 degrees, so I had to cut it off the standard exhaust rotate 90 and weld it back on. A bit like this...
Capture.PNG


You also need to be running a remap or get O2 spacers so you dont get an engine light warning you the cats are malfunctioning (or removed :wink:)
 
That's great info, thanks :thumbsup:

I wouldn't be able to ask for a link to where I can buy that intercooler could I?

I've already got a remap from Evolve who have said that if I added downpipes, they can easily tweak it to make use of them and cancel the error though I'm not sure if I want to deal with any mot issues. Have you gotten through mot with them alright? Also, how much difference do the downpipes make to the exhaust noise, any drone or unwanted reverberation?
 
If you check the intercooler and downpipe text in my previous post you'll see they are already links to where you can buy them :D

Cat removal isn't an issue for the MOT, the secondary cats are more than capable of reducing the levels well below the fail mark.
I posted an image of my co2/HC readings in another thread some time ago - There was no difference before/after cat removal.
I think the primary cats are designed for reducing the emissions when cold. As soon as the car warms up the secondaries are more than good enough.

Exhaust note is a little more 'raw', definitely louder but not a lot.
 
Nick9one1 said:
If you check the intercooler and downpipe text in my previous post you'll see they are already links to where you can buy them :D

Cat removal isn't an issue for the MOT, the secondary cats are more than capable of reducing the levels well below the fail mark.
I posted an image of my co2/HC readings in another thread some time ago - There was no difference before/after cat removal.
I think the primary cats are designed for reducing the emissions when cold. As soon as the car warms up the secondaries are more than good enough.

Exhaust note is a little more 'raw', definitely louder but not a lot.
Click to expand...

I thought recent mot rules meant a fail if the system has been tampered with in any way? :?
Rob
 
Nick9one1 said:
If you check the intercooler and downpipe text in my previous post you'll see they are already links to where you can buy them :D

Cat removal isn't an issue for the MOT, the secondary cats are more than capable of reducing the levels well below the fail mark.
I posted an image of my co2/HC readings in another thread some time ago - There was no difference before/after cat removal.
I think the primary cats are designed for reducing the emissions when cold. As soon as the car warms up the secondaries are more than good enough.

Exhaust note is a little more 'raw', definitely louder but not a lot.
Click to expand...

I blame technology, if it wasn't for technology I wouldn't have missed that :oops:

Thanks again! Good to hear there's no mot trouble, I think I'll look more seriously at doing this too :thumbsup:

Don't quote me but I think it's a visual thing Smartbear, if they can see the cats are removed then it's a fail but the Z4 cats are so hidden away they'll have a real hard time finding them so focus instead on the secondary cats.
 
I wonder what Improvement I could get on my 35i with a stage 1 map plus a larger intercooler. Mine has a Miltek system with middle cats deleted.
 
Nick9one1 said:
I was expecting less of a difference than I noticed between stock and stage 1+, but wow I was wrong!
The car seems transformed - I get 5th gear wheelspin if not careful!
Click to expand...

Wow! That is tempting lol. Stage 1+ is already such a huge improvement over stock too!
 
Nick9one1 said:
Intercooler was very easy to fit, taking about 1/2 an hour. The factory pipes clip straight in like they do on the stock intercooler.
Click to expand...

£200 for an upgraded intercooler is a bargain. Do you have any MHD logs that show long multiple gear pulls to see how this is controlling the intake air temps?
The stock setup on the Z4 isn't terrible but I've noticed when keeping my foot planted above 120mph the IATs do start to climb very quickly and the ECU starts to restrict power.

Regarding the install; Was this install done from the top or from underneath? What parts needed removing to get the intercooler out and the new one back in?
 
I haven't bought the MHD logging pack yet, but will do, then post some logs.

It was very easy to install from below. I already had the plastic undertray removed so it was just a case of removing two torx screws and the clips that join the intercooler to boost pipes.

The new intercooler is a bit tighter (due to being bigger) but fits well. It connects to the factory plastic boost pipes with the factory clips.

Probably took 40 mins to install.
 
Nick9one1 said:
intercooler and downpipes were both from China. Both really nice quality, as good as anything I've seen triple the price.

Intercooler was very easy to fit, taking about 1/2 an hour. The factory pipes clip straight in like they do on the stock intercooler.

Down pipes were a lot more difficult. Again the fit/build quality was great, but access is very tight under the car.
Also, either on the 335 or LHD drive cars (not sure which), the flange is turned 90 degrees, so I had to cut it off the standard exhaust rotate 90 and weld it back on. A bit like this...
Capture.PNG


You also need to be running a remap or get O2 spacers so you dont get an engine light warning you the cats are malfunctioning (or removed :wink:)
Click to expand...

Looking at the AliExpress link the intercooler there appears to be painted black. The picture you posted is unpainted. Did you request a different colour or is the link wrong?

Think I'd prefer the unpainted stock look over the black one.
 
Mines black exactly like the Ali express link.

I didn't take a picture of it next to the stock intercooler so used that image in the first link instead.

IMG_20181026_162015.jpg
 
Ok. I'll get one ordered. I've seen a few logs on bimmerboost and e90post which show it performing better than the stock one. Pretty much equal to the VRSF 7" one.
 
R.E92 said:
Ok. I'll get one ordered. I've seen a few logs on bimmerboost and e90post which show it performing better than the stock one. Pretty much equal to the VRSF 7" one.
Click to expand...

It's a clone of the vrsf I believe :?
 
Smartbear said:
I thought recent mot rules meant a fail if the system has been tampered with in any way? :?
Rob
Click to expand...

You're correct, but only for diesels (cats and dpf). Petrol cars can have the cats removed/modified if they still pass the emissions test.

The advantage of removing the front cats is that if the rules do change for petrol cars in the future, it's not possible to tell they have been removed. The cats aren't visible from the top, and the undertray hides everything from below.
 
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