GTM Libra (Honda Engined)

I've been in a ek9 with b20 the torque compared to b18 was a hell of alot more noticeable be next best thing to turbo..isn't it better to use b18 from mb6 has compression is better for turbo over teg b18
Not really, it's easier/cheaper to do it if you want to turbo/supercharge it as it is as it has lower compression... but if internal modifications are planned then it makes no real difference and the engine is already in the car.. Plus I've already got the Type R head/cams etc.

I know my current engine is a good runner having just rebuilt it, don't really want a B20 and I've gone off the idea of Turboing it. Don't really want a Jackson supercharger either so that leaves me with Rotrex.
Little update, prepping the car for paint has unfortunately been more time consuming than I'd hoped... I'm now dropping the car off on the 18th, not this Saturday (4th). Really wanted to hit the date agreed but it was just stressing me out too much and not something that should be rushed.

In other news I managed to pick up some nice H beam rods complete with 9mm ARP bolts and a full new ARP head stud kit for about half price off someone who collected the bits and had to have a change of plan... just going to keep picking up bits as I go, but the main thing is I'm still on the look out for a C30-94 Rotrex.

Had some correspondence from Z Cars too, sounds like the kit is about a month away from manufacture.
So I've been doing some digging

I'm a sucker for a challenge and none of the off the shelf rotrex kits are going to fit this car, as they all fit on the exhaust side where I have no space. The immediate problems I've faced while designing this in my head are the availability of 4 rib belts, and to run it with a single serpentine belt I will need a double backed belt so I can run the rotrex off the back of the belt, otherwise it'll be spinning backwards with the engine.

There are not many 4 rib double sided belts on the market at all, furthermore I think a 4 rib belt is pretty poor for a supercharger. This got me thinking, is a 6 rib pulley available???

The answer is/was no... however.. while searching I stumbled across a Honda D series forum, where a few people have built D16 strokers with a D17 crank. What they found was that the D17 crank snout was much bigger so they either had to use the D17 pulley/oil pump, or turn down the snout to use the original bits. Then some further searching on this topic revealed that some people had used B16/B18 crank pulleys on the D17 crank.... therefore a bit of reverse engineering tells me a D17 pulley should fit a B18C crank... and... it's a 6 rib pulley. Bingo!

I've also found out that the alternator pulley is the same ID too... so I can convert to 6 rib for peanuts and already have the bits on the way to check offsets etc. but Any minor difference in offset should be easy to put right, if needed.

Now as a lot of OEM serpentine belt setups utilise a 6 rib double sided belt, this means there's a myriad of belt lengths available off the shelf.

I'm just going to keep collecting bits but as far as I'm concerned the hard bit of designing it out is already done now and I can run a better belt than the other kits and run the rotrex above the alternator where I have some space.

Little sketch, obviously a tensioner needs to go somewhere too, maybe near the alternator

Shaping up to be an interesting project, two things caught my attention though.
1. Is the d17 pulley the same diameter as the bseries one? Obviously this will effect the boost pressure the charger makes, easily adjusted with a change in charger pulley size but worth mentioning i felt.
2. I think your going to want more belt around the charger pulley than in the sketch, nearly all the setups ive seen on all models of cars using a supercharger have as much belt surface as possible on the charger, this lessens the chance of belt slip obviously.
Id go from the alternator striaght up to the charger, then right around the charger with either a tensioner or a pulley very close afterwards almost directly below the charger.

Edit: **** just realised you need to spin the charger the otherway.
Do we have the space to mount the charger 180degrees? So what is in the sketch the pulley side, becomes the compressor side?
Nope it's got to be that way round, can get more wrap on the charger by adjusting the position of the top two jockey wheels, higher and closer together. It is just a rough sketch after all.

This is the kraftwerks setup

Pulley diameter wise, I'll know when I get it, but as you say it doesn't really matter.. if it's the same then I'll just use the same rotrex pulley as the kraftwerks kit, if not then I'll have to do some calcs and go up or down a size... stuff like this is so minor I'm not fussed about it, main thing is I know it's actually do-able now, as before finding out these pulleys would fit etc I was beginning to think it was a non starter.
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Slightly better sketch, showing the tensioner and better positioning of jockey wheels for more wrap. Having had a look at other belt layouts of OEM supercharged and retrofits I don't think the alternator needs any more wrap than this, some even have less. It will be well tensioned and 50% wider belt than standard so I don't foresee an issue.

Yeah that looks much better. Where is the tensioner going to be mounted? A backing plate for the charger?
I see procharger offer reverse rotation superchargers which would simplify the belt run, fat chance of me finding one of those reasonably priced though, I'll shoot them an email but I expect I'd have to order one new direct to get exactly what I want. At least with the rotrex I can just wait for one to come along. Worth asking the question though I guess.
Just had an update, Z cars are finally on with the rear trailing arm conversion kit

Hopefully get the car back from being painted next week too. Haven't given much more thought to the rotrex idea, in fact I think I'd rather keep it NA.
Nice update, shame about the boost idea being scraped.
It's just a bitch to figure out which ever way I look at it but to be honest I think the car suits NA more anyway. It was a welcome distraction to all the bodywork I was doing
Shame you cant switch to Kseries. so we thinking NA b20 now?
I could, but don't really want to. It sounds like I'm not happy with the engine and I actually am I just love messing. In future maybe a B20 or sleeve the B18C. At least then it's still essentially a tuned type R engine and stronger if i get the itch to boost it later on.
They are too easy to play with these engines arent they lol
Yes! I think if I still had my old car with the Rover K I'd just be content with what I had but these Hondas are so tuneable it's hard to ignore