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Creampuff's Rotrex

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Old 09-30-2017, 11:35 AM
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Default Creampuff's Rotrex

Mention this in the Morpheus thread but figured out I'll start a new one.
I'm putting a Rotrex on Creampuff and as per freaking usual decided to toss the easy button in favor of a better setup.
Big change is that unlike all setups that are made for cars equipped with PS and AC, I'm building mine as if it goes on a race car - setting the blower as low as practically possible in order to lower Cg.
This is the first mockup, and the blower sits over a foot lower than where it normally does -



Currently waiting for the tensioner and idler to arrive so we can program them in and send the files to get cut.
Discuss.
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Old 09-30-2017, 11:52 AM
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I haven't studied the pictures heavily, but after doing one rotrex install, rather than low cg I'd focus my location on ease of intercooler and intake routing. I'm sure you have...unique...plans for both. That location makes me worry specially about steering rack and radiator hose.
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Old 09-30-2017, 12:13 PM
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The rotrex clears both rad hose and steering rack in this location.




I'm not using any kit but rather making my own, IC piping is fairly easy with the side mounted IC I'll be running -



Simple-ish pipe across the engine bay on the bottom into the IC and a short outlet into the TB.
Only pipe that needs to make a tight-ish turn is the blower intake which has to do a 180 degree turn, but a silicone elbow pretty much solves that issue.
I will fab up a heat shield under / around the header.
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Old 09-30-2017, 11:22 PM
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In for awesome.

I see Curly's concerns, especially with the intake hose. But we are mere mortals without the fabuloussss fab skillz (and appropriate tools on hand as well), so I'm sure you'll make it work.
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Old 10-01-2017, 09:16 AM
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How will you be driving this from the crank? Are you using the ac/ps 4 rib, an add on or custom? Auto belt tensioner? How about the mixing manifold clearance with the mounting bracket? These are questions I had to deal with on mine.

I just stuck an alternator over there and there is room. I actually picked up a windowed longblock with accessories and a subframe/steering rack so I could fab off-car, it was super helpful. The options for getting even 2.25" charge piping in and out of that area are surprisingly limited, and it looks like the intake pipe will need a tight bend radius.

with that IC location, have you considered moving the alternator and mounting on the cold side? I stuck an MP62 under the intake manifold.

Oh, and I have personally decided that aluminum is a poor material choice for crank driven accessory brackets. I would consider steel as an option.

LOVE diy SC builds!
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Old 10-01-2017, 09:21 AM
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Just looked at your other thread, you are way more advanced than I am, I am sure you have already considered everything I mentioned....
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Old 10-01-2017, 11:04 AM
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Very cool. Welcome to the Rotrex club. I think you'll be impressed with the NA like power delivery.
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Old 10-01-2017, 01:14 PM
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Originally Posted by Ted75zcar
How will you be driving this from the crank? Are you using the ac/ps 4 rib, an add on or custom? Auto belt tensioner? How about the mixing manifold clearance with the mounting bracket? These are questions I had to deal with on mine.
The outer portion of the crank pulley is inline with the blower so that's an easy one, the bracket will include an auto tensioner and an idler pulley.
It's going to be a 4 rib for starters, but the location of the blower (fore-aft) will allow switching to a different crank pulley and driving it with up to 6 ribs belt if I decided to do so.
Water neck clearance is fine and there's no mixing pipe on my car.
Originally Posted by Ted75zcar
I just stuck an alternator over there and there is room. I actually picked up a windowed longblock with accessories and a subframe/steering rack so I could fab off-car, it was super helpful. The options for getting even 2.25" charge piping in and out of that area are surprisingly limited, and it looks like the intake pipe will need a tight bend radius.
I am using an old worn out engine to do the mockup along with measuring on the car.
I'm not super worried about the tight-ish bend radius of the intake pipe pre-blower as I doubt this will ever cause a restriction, especially since I'm planning on running a velocity stack into the elbow (there's room upfront, so why not).
Post blower it's a different story and the routing of the piping is decent in terms of length and bends.
Originally Posted by Ted75zcar
with that IC location, have you considered moving the alternator and mounting on the cold side? I stuck an MP62 under the intake manifold.
I actually considered moving the alternator to the back of the car altogether in order to set the Rotrex where the alternator currently resides... Wasn't sure how much of a problem this will cause in terms of charging when the car isn't moving and since I'm running a small battery this smelled like a serious issue that should be avoided.
It would probably be A-okay running a big deep cycle battery, but that means the car is heavier...
Originally Posted by Ted75zcar
Oh, and I have personally decided that aluminum is a poor material choice for crank driven accessory brackets. I would consider steel as an option.
I'm going to use 3/8" thick 7075 for this bracket, and a Steel brace.
Not expecting any issues.
You can see the mounting flange for the brace on the block in the first pic.
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Old 10-01-2017, 03:48 PM
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Right on, sounds like you have already thought about all this stuff. +1 for the fore/aft adjustability.
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Old 10-01-2017, 03:51 PM
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I ran a OA2076 twinscrew to 17Krpm+ with a 4 rib, so I bet you will be just fine as long as you control belt orbit.
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Old 10-01-2017, 04:27 PM
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Originally Posted by Blackbird
I actually considered moving the alternator to the back of the car altogether in order to set the Rotrex where the alternator currently resides... Wasn't sure how much of a problem this will cause in terms of charging when the car isn't moving and since I'm running a small battery this smelled like a serious issue that should be avoided.
It would probably be A-okay running a big deep cycle battery, but that means the car is heavier...
Hotside alternator?

https://www.miataturbo.net/race-prep...2/#post1389688
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Old 10-02-2017, 03:21 AM
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Great to see others jumping on the Rotrex train, mine should be here this week! Subbed.
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Old 10-02-2017, 10:48 AM
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Originally Posted by aidandj
Looked at it briefly, I don't know that this is a great location for the Rotrex, between the intake manifold brace and the sandwich plate for the oil cooler, it's pretty cramped.
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Old 10-02-2017, 12:42 PM
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Have you considered how the belt will affect IC routing? I'm sure you have, it just looks light it might get tight with the rad hose there.
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Old 10-02-2017, 01:46 PM
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There's room

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Old 10-02-2017, 11:29 PM
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So much room for activities...
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Old 10-03-2017, 08:00 AM
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Originally Posted by Blackbird


So much room for activities...
​​​​​​​Does the motor still count as being air cooled if you have an oil cooler?
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Old 10-03-2017, 08:30 AM
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Originally Posted by Blackbird
There's room

Well that solves that problem.
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Old 10-03-2017, 10:15 AM
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curious to see how much weight this ends up dropping. Saw on facebook you mentioned the front clip section you cut off weighed 38.x lbs.
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Old 10-03-2017, 11:41 AM
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Originally Posted by x_25
Well that solves that problem.
There wasn't a problem to start with, this is a weight saving measure.
Everything that I'm doing with this Rotrex installation can be done with the tub in place as is, all it would've required is a clearance hole for the IC outlet pipe where the passenger headlight bucket is.

Originally Posted by Padlock
curious to see how much weight this ends up dropping. Saw on facebook you mentioned the front clip section you cut off weighed 38.x lbs.
Yeah, the part in the pic was a hair over 38 Lbs... I couldn't stand the thought of adding weight to the car with the Rotrex bits, so this should even out or at least be fairly close to even.
I am taking many other weight savings measure at the same time though so the car will end up lighter for sure.
The door skins are being replaced with Carbon door skins (~15 lbs savings there), most of the rear sheet metal went away, there's a bunch more front sheet metal to cut etc..

​​​​​​​
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