GTM Libra B18C

[alfie2244]

750kg + B18c6 = big smiles + Honda out of the box reliability....that would do me fine

[Ant_ITR]

Yazza54 said:

Ant_ITR said:

if you were to go turbo you would be better selling the b18c6 and getting a b18c4 found in the mb6 civic, they are a lower comp as standard and take better to turbo conversions, the b18c6 you have now would sell for around £2kish and you should be able to pick up a c4 for around £500

I know but there's something nice about having a unit you know works. I can easily drop a set of C4 pistons in anyway. Plus it remains a type R with its better balanced crank and type R head/cams. I'm not looking to do a major transplant, if I do anything at all.

TBH initially I was just thinking of cams and map, then I thought that wouldn't make much difference so started thinking about sleeving the block and now here we are talking about bloody turbos

On my dc2 the best thing i did if you havent already was get Hondata S300 management for it, it only gave me about 4bhp over what it was on the standard ecu but the drivability of it was so much better, with a 4-2-1 skunk2 manifold and 2.5 inch bore exhaust and the mugen airbox it made 205bhp at the fly and 152ft lb of torque. I would also look at changing your intake, the whale penis although it sounds really good on vtec suffers really badly with heatsoak and will probably be loosing you power. Sorry if you have covered this stuff before i havent really read previous pages

[Yazza54]

Ant_ITR said:

Yazza54 said:

Ant_ITR said:

if you were to go turbo you would be better selling the b18c6 and getting a b18c4 found in the mb6 civic, they are a lower comp as standard and take better to turbo conversions, the b18c6 you have now would sell for around £2kish and you should be able to pick up a c4 for around £500

I know but there's something nice about having a unit you know works. I can easily drop a set of C4 pistons in anyway. Plus it remains a type R with its better balanced crank and type R head/cams. I'm not looking to do a major transplant, if I do anything at all.

TBH initially I was just thinking of cams and map, then I thought that wouldn't make much difference so started thinking about sleeving the block and now here we are talking about bloody turbos

On my dc2 the best thing i did if you havent already was get Hondata S300 management for it, it only gave me about 4bhp over what it was on the standard ecu but the drivability of it was so much better, with a 4-2-1 skunk2 manifold and 2.5 inch bore exhaust and the mugen airbox it made 205bhp at the fly and 152ft lb of torque. I would also look at changing your intake, the whale penis although it sounds really good on vtec suffers really badly with heatsoak and will probably be loosing you power. Sorry if you have covered this stuff before i havent really read previous pages

I know they suffer from heat soak in a standard car but that's not entirely applicable to this in my opinion. On this thing there's not many other options, when I first got the car with the b16a2 in it there was just a little cone filter sat on the TB, directly above the exhaust silencer and somewhat shrouded by the boot cut out so mega heatsoak...! I put the whale cock setup on to get it away from there, granted it's still above the manifold but not directly above, it's got a naca duct to it and I've made a heat shield for the manifold... theres also two large ducts either side of the clam so on the move I don't honestly believe heat soak with a whale setup is any worse than it'd be with any other setup.

It already has a 2.5 inch system throughout and 4-2-1 PLM manifold, with a straight through silencer and currently decatted. I've been thinking of buying a S300 so I can get the most out of what I have and I've always got it there for the future flexibility too.

[Yazza54]

Another idea I had was a B20 Block with B18 rods and crank, I think that makes around 1932cc, kinda like a poor mans way of making a 84mm B18c.. I know the sleeves are reportedly weaker in a B20 but that only becomes apparent under boost or detonation from what I gather. Plus using a B18 crank and rods at least retains a slightly better rod/stroke ratio.

I'd love to rotrex it but the problem remains with lack of space.

Will park all these ideas until the car is painted and Z cars kit is on...

Edited by Yazza54 on Friday 17th February 10:32

[dom9]

NA for the win

[Yazza54]

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.

[Yazza54]

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

Edited by Yazza54 on Monday 6th March 16:56

[rdodger]

Top interwebing there Ryan

If your sketch is near accurate I think you may need more wrap around the alternator. Other than that it all sounds very reasonable.

[Yazza54]

I agree, it's not accurate at all just shows the general layout. I could do with taking some measurements so I can CAD it up. For now I at least know that it's a go-er as before figuring these details out it wasn't looking do able without lots of custom components and ££££££.

I think the top two jockey wheels could be slightly higher and closer together too for more wrap around the charger pulley.

This is how the kraftwerks kit is

Edited by Yazza54 on Tuesday 7th March 07:06

[Yazza54]

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.

[WillisRR]

Ohhhh hell yes! This is awesome! Have a huge soft spot for B series motors after having Civic and Integras.

Having one mid mounted in something like this is just dreamy!

[Yazza54]

Just had an update, Z cars are finally on with the rear trailing arm conversion kit

[Sway]

Awesome. Proper fabrication!

Seems I'd missed a few of the recent updates - I don't know how applicable it is but the Kraftwerks rotrex kits for the mx5 were plagued with problems - mounting plates that flexed like mad, alignment issues, all sorts!

I do agree however, I can't think of many things better than a rotrex for this application.

[Yazza54]

Sway said:

Awesome. Proper fabrication!

Seems I'd missed a few of the recent updates - I don't know how applicable it is but the Kraftwerks rotrex kits for the mx5 were plagued with problems - mounting plates that flexed like mad, alignment issues, all sorts!

I do agree however, I can't think of many things better than a rotrex for this application.

Yeah looking forward to getting it thrown on then I'll take it somewhere for a full set up. Should get the car back from the paint shop next week too.

Engine wise I'm thinking I might just keep it NA after all. But we'll see... it's a bloody brilliant engine as it is.

[dom9]

NA for the win!

Looking forward to more updates

[alfie2244]

Yazza54 said:

Engine wise I'm thinking I might just keep it NA after all. But we'll see... it's a bloody brilliant engine as it is.

[Yazza54]

Just had a chat with Chris at Z cars, they have made some minor adjustments to the kit and it will have wider track built in, as many people were running the original kit at its widest possible adjustment. This is good news for me as there will be more clearance for my engine and box as the B18C is longer than the Rover K. They are also designing replacement top wishbones that are adjustable as it is near impossible to get the geometry right on a standard libra. The factory suggested you shim the wishbone mounts to achieve this which is just a terrible and time consuming method. Just waiting on a price- hopefully not too eye watering..!

[Yazza54]

Finally got the car back painted. Can't say it's the best job in the world but it looks a damn lot better... I think with me knowing where all the bad bits were etc. I'm always going to be more critical than most people would be. It looks very striking now. Get my new lights and plates fitted and then I probably won't be touching the car until the Z cars kit is on.

[Pistom]

Is it done now?

[Yazza54]

Uh ohhhhh