Monkey mans power adder

[Machine monkey]

So I was going to wait until the project was finished. But i may weel bee needeing to ask questions and get a little advice to finish off so here goes. Bear with me this may be a long read and i want to give a fairly full background why i have done this and this way. So when the majority of you tell me i am mad and it won’t work (which is fine we are all entitled to opinions) And you could be correct!! But you may just understand why i went this route.

Firstly a first start up video.......
http://redirect.viglink.com/?format=go&jsonp=vglnk_149267068723918&key=c01811c375502cb92bcff8bea3a1bf27&libId=j1q1kcy7010004ri000DAmtxhkznu&loc=http%3A%2F%2Fwww.z4-forum.com%2Fforum%2Fviewtopic.php%3Ft%3D93757%26start%3D540&v=1&out=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D94S2WWC_l6s&ref=http%3A%2F%2Fwww.z4-forum.com%2Fforum%2Fsearch.php%3Fsearch_id%3Degosearch&title=What%20have%20you%20done%20to%20your%20car%20today%3F%20-%20Page%2037%20-%20Z4-forum.com&txt=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D94S2WWC_l6s

So after owning my car and modding it for 4 years. Spending lots of time cash on suspension brakes cosmetics (although not my main concern we all like to look at a car and think yes that’s mine right!!) It was finally time to try and get a little more power.
The options
1 bolt on S/C kit. Well these kits are great and are good value for money and you know they will work. But i wanted to build something myself and something that would challenge me.
2 engine swap. A Lexus v8 was very close to being brought and put in the car. It was affordable and we (me and my best mate Chris have experience with them in the Toyota supra build we did) But i wanted to keep it a straight 6.
3 Nitrous cheap power adder but not really that good unless you like just driving in straight lines.
4 so it was going to be a turbo build.



The reason i have not put that in the title is because of a previous thread. I don’t really fancy this one going in the same direction. Project or thread....

So the build was going to be mega cheap, Mega quick and dirty, And that didn’t happen!! I was going to sling a cheap eBay turbo under the car where the secondary cats live. And just map it using the standard ecu and see what happened.

But after a bit of looking into in and freeing up a little more cash i have gone about it in the way I had always intended. I have stuck the turbo out the back where the back box use to be.
Why!!!
1 heat build up under the bonnet from turbos can effect so many other things. And you can end up chasing your tail fixing things
2 Space is really limited on a RHD z4 on the exhaust side.
3 There is no reason not to do it.
4 I wanted to do it that way.

So I asked myself before the build. In fact me and Chris discussed it at great length over many many beers on many many ocastion. I wanted more power to build something unusual to use my skills to build something never done on a z4. And also to have reliability and drive ability. But to also be crazy and a bit of a handful when I wanted it to be. I also wanted something that has future power possible in future years.

So a turbo was the best option. And what we came up with was using a holset (great strong reliable turbos. Mine is a hx32 it’s quite a rare thing big intake small exhaust side. This turbo will provide up to about 500bhp eventually maybe one day… They have been used on 2.0l engines providing boost from as low as 2500 rpm and giving 500bhp Mine will hopefully be providing boost from about 3-3500 rpm giving me a normal ish z4 to drive around in day to day. And then on track drift days or spirited driving much more power at higher revs. I have modded the turbo so it’s now an external waste gate not internal for better boost control.

I am using a piggy back ECU (perfect power smt8) As I wanted to keep all the standard BMW features traction control and so on witch is almost impossible with a standalone. Also it’s a cheaper option…. This ecu will control fuel timing boost and has a few other really nice features. It can run 2 maps witch switch a flick of a button so I could run a 300bhp map on the road and a 400bhp map on track say.

I will update this post later with pictures and a bit more detail about the build and how it happened over the next few days.

But I would lie to say thanks to a few people who have really helped so far.
My mate Chris
Stuartt who wired in the piggy back and did such an amazing neat job. And without your help I would not have been as relaxed as I am now about the project.
SK93 he will be providing much more help.
Mac and Cj who have helped out on a few technical questions.

 

[MrPT]

Boom, out of nowhere!!! Can see what all the winking and behind-the-bike-sheds muttering from some members has been about now.

Must admit I had no idea that rear mount turbos were a thing. The charge cooling must be amazing. Can you run Aluminium pipework back up to the engine or does it need to be S/S? Very cool mod... and lots of tuning potential eliminating lag etc.

 

[Chris_D]

Top bombing Mat!
can't wait to see updates....

 

[Rally]

Looks awesome Matt can't wait for a ride and to book my car in

 

[Stu Boy]

Very interesting location for the turbo, something I've not heard of before. I imagine there's a shed load of work involved
I'll be keeping on eye on this thread and potentially looking over my shoulder on the road :wink:
Good luck MM

 

[Steve84N]

3 There is no reason not to do it.

Erm, more turbo lag...

It will also be less efficient being so far away from the lovely hot air coming out of the engine but more power is more power and the advantages stack up here.

Good luck, seems like you're more of the way there than Johnny ever was.

 

[bmwaddict]

I too never knew a rear mounted turbo was a thing! Good luck Mat!

 

[kis]

Nice project! Looking forward to more updates!

 

[-Tom-]

This looks like fun mat! I'm sure you're in your element in the man cave with this. The turbo noises coming from the back is going to be really odd, and loud with the roof down behind you

 

[Smartbear]

3 There is no reason not to do it.

Erm, more turbo lag...

It will also be less efficient being so far away from the lovely hot air coming out of the engine but more power is more power and the advantages stack up here.

Good luck, seems like you're more of the way there than Johnny ever was.

Not sure about that, turbo's depend on exhaust gas velocity & not temperature to create boost pressure-the only issue I can think of is the convoluted route/length of pipe back to the inlet side of the engine, as the more joins=more potential for leaks?
I'm sure mat will overcome though
Is it plumbed into the engines oil/coolant supply for cooling and lubrication?
Rob

 

[Machine monkey]

3 There is no reason not to do it.

Erm, more turbo lag...

It will also be less efficient being so far away from the lovely hot air coming out of the engine but more power is more power and the advantages stack up here.

Good luck, seems like you're more of the way there than Johnny ever was.

And here we have it.. The question i was expecting

Steven your right turbo lag is a problem. But turbo lag is a problem for well every turbo car. There are some very clever things you can do to eliminate it but they tend to be quite involved and i may employ some of them later.

I honestly don’t know what the lag will be like on this. But if you look up remote or rear mount turbos. It seems to be not as bad as what you would initially think. Remember it’s a closed system so management of exhaust and boosted intake are important . So a hose pipe that’s empty will take a while for water to come out once a tap is turned on. A hose that’s full the water comes out quickly. So having valves waste gate and dump and controlling them accurately can help this problem quite a lot.

Let’s also consider that some not all turbo lag can and is very often caused not just by exhaust gas before or getting to the turbine. But gas in the exhaust after the turbine back pressure. This can cause a turbo lag as it can’t spine as quickly. So any badly designed system can have lag. Even if the turbo was bolted as closely as physically possible.

We have taken every precaution I could to limit lag. The exhaust will be heat wrapped to minimise wasted energy. And as mentioned the turbo its self was chosen very specifically and the exhaust was designed to work as well as I can get it on my budget and without proper headers (at the moment)

 

[Roundozo]

:
Is it plumbed into the engines oil/coolant supply for cooling and lubrication?
Rob

This is what I was thinking? Is it a floating bearing inside the turbo? Are you going to run an oil feed line from the engine or have a standalone system?

It's a school day for me. Never heard of rear mounted turbos. Bet the noise will be awesome!

 

[Machine monkey]

3 There is no reason not to do it.

Erm, more turbo lag...

It will also be less efficient being so far away from the lovely hot air coming out of the engine but more power is more power and the advantages stack up here.

Good luck, seems like you're more of the way there than Johnny ever was.

Not sure about that, turbo's depend on exhaust gas velocity & not temperature to create boost pressure-the only issue I can think of is the convoluted route/length of pipe back to the inlet side of the engine, as the more joins=more potential for leaks?
I'm sure mat will overcome though
Is it plumbed into the engines oil/coolant supply for cooling and lubrication?
Rob

Yeah your right the route back to the engine is a massive sacrifice. But there was no way of running it back to the car unless it was right next to the exhaust. I will have cooler charge temperatures so i am using a restively small intercooler. Lots of care has been taken to avoid any leaks. Had nothing this far.

It runs off its own oil system mounted in the boot pump and regulator to control feed. Thermostat housing oil cooler. Then return pump back. It’s been the most difficult part.

 

[Machine monkey]

Guys like I said I wanted to build something unusual. Not been done do I know if it will work no!
Do I know if I will have problems yes. This is all part of the journey of doing things your way and having an idea.

 

[Ducklakeview]

WTF!!!
Posting this after reading the first couple of paragraphs Mat - You kept this quiet you old dark horse!!

Going back to continue reading - WITH INTEREST

Mike

 

[Machine monkey]

So the tank fits behind the rear wheel arch. With the return pump below it under the car next to the turbo. The feed and other stuff is tucked away in the boot.

 

[-Tom-]

So is this actually up and running Mat? Or very much in testing rather ?

 

[Machine monkey]

So is this actually up and running Mat? Or very much in testing rather ?

I have converted the car to hydraulic steering, Fitted a lightweight flywheel and proper single mass clutch, and then started this. It runs but is not finished. I have run out of cash and time. I have sacrificed any spare time burned myself out. 60 hour weeks at wo4rk with commuting this project being a new dad plus doing stuff for people hear to earn a bit extra to fund the turbo. I am just in need of a brake to recharge and attack it again with enthusiasm.

If anyone wants it done quicker please donate money and time

 

[-Tom-]

Amazing stuff, you kept that quiet on here and then boom - a mutant ! I can't wait for videos in the future with sound ! And congrats on baby MM, I missed that too!

 

[markplant]

Well done mat glad it's getting there