7 Port supercharged project help!
Turbo Mini Forums

Good Evening all,

I am planning a project that I am wanting to start collecting parts for (so the hit isnt so big when it comes around to it). My best mate has just purchased an "S" Pack Rotrex kit for his mini from Specialist Components they reckon with his spec he should be looking at getting around 180BHP.

So naturally I want to start researching my next build... I have a 7 port engine in the garage which I have removed from one of my current cars to fit a promotive conversion which I am still working on.

I was thinking that I would like to build a 7 port supercharged engine seeing as I have the head. I would like to go injection as I feel it would be more reliable and easier to get max power from it. I already have a Polestar Turbo ECU, so I can wire that up to suit.

So my questions:

- Do I need any form of special crank for a supercharged engine running around 180BHP or will a decent fast road one (balanced and lightened - like I already have do the job).

- Conrods and pistons I was thinking of going for MED conrods and omega pistons (1293cc) is this the best option?

- Intake - so a couple of options here, I was initally looking at fitting a pair of the Jenvey Heritage DCOE 45 throttle bodies and mounting a plenum the other side of them as I fancied the look of the DCOE's, however I have seen on Wil_h's thread he has a singular TB prior to the plenum and individual injectors (same as heritage) into each port. Is there an advantage/ disadvantage to either setups? Also I noticed Jenvey do short 30mm TB's does anyone have any experience of these as they might help with space saving at the front of a roundnose along with some stubby MED inlet stubs? PROS/CONS?
https://www.burtonpower.com/jenvey-2x45mm-s...0mm-tsp45i.html

- Gearbox wise: I have a SCCR box at the moment which would handle the power but would it be any good on a SC setup? Has anyone had any experience with the Minispares evolution helical gears?

- Supercharger wise I have a couple of options, I have an M45 charger and old Vmaxscart kit laying around, I have an SC12 supercharger hanging about but I was mightly tempted to go with the Rotrex C15 charger like SC use and tuck it down in the front out of the way. Any pointers on this from anyone? I dont wish to go turbo route.

Any advice on "ultimate" supercharging engine ideas, things to avoid and things to get? I plan on piping up the system myself and building the engine etc myself (I am a mechanical engineer but would be my first "blown" engine build).

Thanks again and sorry for the above essay!!

Sounds like all you need is the search button.
And some time.

Not all the answers will be found here as you don't want to go turbo. But there's a wealth of info on here.

Outside the box

double post

Edited by monsterob on 6th Apr, 2020.

Outside the box

1. You don’t need a special crank. It is RPM that kills cranks and with boost you won’t need to go crazy. People put 200bhp through a stock crank with limited revs.

2. Not sure who supplies MED rods, but personally have used Saenz rods from SH engineering. They are a very nice rod and I believe have just been redesigned again to further save weight.

3. Single TB is easy to package and it doesn’t make to much difference over ITB. I’m using a single.

4. It will be fine if in good order. A couple of people are using the wide helical headsets and no reports of issues yet.

5. Not sure personally. Rotrex is nice packaging wise!

6. Fit a big intercooler and personally why not fit a turbo? Considering your going for 180bhp, it would be a lot easier! Also have you experienced that sort of power in a mini?

Hello mate, Ive searched regarding the throttle bodies but it doesnt seem like anyone has really discussed that in depth.

And supercharger options I havent seen any threads where people have discussed in depth which option would be the best for a 7 port application?

Thanks for your reply though, I have done alot of reading and research through the wealth of information on this brilliant forum.

Hi Jonny F, thanks for the great reply.

MED rods are arrow rods I believe but more refined and lighter but still steel, but yes I also saw the SH engineering ones and they were on my list so thats good to know!

Great to know about the single TB, as that may make the installation cheaper/ neater. Would a single 50mm TB be sufficient? I am guessing so bearing in mind the piping is 50mm generally.

I have a plan to custom make a large intercooler front mounted so thats good.

And turbo wise ive always preffered a supercharger really, nothing against turbo just personal preference really.

And yes ive experienced a mini close to 180, more like 170ish BHP. Crazy power, but I have to match my mate so thats the criteria really haha.

Thanks again for the reply.

one consideration witht he inlet, if you have a plenum and one thb then you should get a much more consistent map pressure signal.

considering people are stuffing 200hp though an HIF44 then 50mm should be fine

charger wise the Eaton is a bit of a dog, the SC 12 should be more efficient.

Hi Joe,

Ah yeah that makes sense with the plenum and signal.

Also agree with the comment on the Eaton compared to the SC12. I havent found out exact cost of a Rotrex one yet/ researched exact model for the application but cant see it being cheap so might end up with the SC12 yet.

Been reading your 7 port turbo build and im very impressed with your work!

cheers,

Sprintex carrgers were fairly effichient as well IIRC, IIRC the sprintex and SC12 are both Lysholm designs?

Ive been away fromt he car for far too long, theres still stuff going on but at a pretty glacial rate.

The Rotrex are dear as anything and if you go supercharged you need to decide if you want low down torque or top end power, Eaton for low, Rotrex for top. SC will sell you a kit bare of the bits you dont want, but its not cheap enough, better to buy it all and modify, then sell off the excess. Its designed to fit an MPI only though so you have to use an MPI block. The supplied Air Filter also doesnt clear the oil takeoff, plus theres severe packaging issues getting everything in there as ideally you want an intercooler or charge cooler. A single plenum and TB is the way to go, someone like TCK will easy make you one. You will also have to run the alternator in a non standard position if you do go Rotrex. I've supercharged my 8 port and its ALOT of work. I've gone from 115bhp to 175 on the same dyno after going down in cam to try and better suit the charger.

Here for the craic..

Supercharged Arden powered

Haha I know where you are coming from there Joe, ive been building my promotive mini for close to 2 years now. Also have a minivan in progress and already starting to plan this 7 port project. I will look into the Sprintex option also!

Richspec... again thanks for the great reply. Yes I might get in touch with SC and see how much certain components are. I was aware of the MPI block thing but as you say I would potentially like to make a fitment similar to theirs but for a normal block but obviously need to relocate the alternator etc. and i might be able to fit a intercooler direct off of the SC and then straight up into the plenum on a 7 port (as obviously a different configuration to the SC 5 port rotrex kit). But I would have to iron out all of those issues as I met them really.

Out of interest what charger have you used on your 8 port? Do you have any pics/ a build thread at all? Sound an interesting build!

I'm running the Rotrex, playlist here on Youtube.
https://www.youtube.com/playlist?list=PLcii...fNbXt06bCdkvD2k

https://www.facebook.com/photo?fbid=1022258...214654227500363

Edited by Richspec on 9th Apr, 2020.

Here for the craic..

Supercharged Arden powered