Building N/A track engine help & suggestions


NIO

NIO

Mini me ej9
Joined
Dec 13, 2008
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38
I have B18C complete engine with gearbox. I'm going to build it for track use only my class is limited to 2000cc. My goal is high rpms (10000) and about 230-240whp and also reliable engine. I have already some build in my mind but I'm looking for some help and suggestions about achieving this kind of power. I don't need suggestions like put cams, rods, pistons etc. (I know that I will put parts like this in my build), so please give opinions based on facts and dyno sheets.
 
This will probably be against the gain of what everyone else will say, but I reckon if you want to spin it that high, you'd want to be looking at de-stroking it with B16B internals and getting it sleeved and bored out to 84-85mm. De-stroking is common in motorsport as you need less low down grunt and more high speed power and reliability which the B16B provides with its excellent R/S ratio.

The kind of piston acceleration (and in turn forces on the rod/gudgeon pins/rod bolts) you will be seeing at 10k on B16B are somewhere in the region of a B18C at 9k. You want to be keeping these internal forces as low as possible if you want to be reliable. Boring it out to 85mm should give you as much torque as a B18C but with the capability to happily rev up to 10k with the right head package.
 
I'm thinking of doing something like this Kozy, but I wonder which block to use b20 with 86mm pistons or sleeved b18 with 86mm pistons. There is another way also building fully b20 reviving it to 8000 rpms or strocking the b18 and reviving it to 8600 rpms because the piston speed with this kind of setups reaches the top speed at this kind of rpms, but for track use we need more horse power at high rpms.
 
Kozy said:
This will probably be against the gain of what everyone else will say, but I reckon if you want to spin it that high, you'd want to be looking at de-stroking it with B16B internals and getting it sleeved and bored out to 84-85mm. De-stroking is common in motorsport as you need less low down grunt and more high speed power and reliability which the B16B provides with its excellent R/S ratio.

The kind of piston acceleration (and in turn forces on the rod/gudgeon pins/rod bolts) you will be seeing at 10k on B16B are somewhere in the region of a B18C at 9k. You want to be keeping these internal forces as low as possible if you want to be reliable. Boring it out to 85mm should give you as much torque as a B18C but with the capability to happily rev up to 10k with the right head package.
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thats some cool advice man. well tech lol
 
NIO said:
I'm thinking of doing something like this Kozy, but I wonder which block to use b20 with 86mm pistons or sleeved b18 with 86mm pistons.
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You won't get 86mm out of the stock B20 as the liners aren't thick enough, so either block will need sleeving. I would personally use the B16B/B18C block as it has a slightly taller deck height. I'm not even sure if you can go up to 86mm in a B series. IIRC, cylinder spacing is only 90mm so you would really be pushing the limits there!

NIO said:
There is another way also building fully b20 reviving it to 8000 rpms or strocking the b18 and reviving it to 8600 rpms because the piston speed with this kind of setups reaches the top speed at this kind of rpms, but for track use we need more horse power at high rpms.
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I personally would not build a long stroke motor for this kind of use, you get the higher internal stresses at lower RPM and in addition you're getting a sizeable increase in piston side thrust into the cylinder walls which only serves to increase friction and will kill piston rings and start burning and contaminating oil a lot sooner than a short stroke engine. Strokers are brilliant on the road as you can really use the extra low down grunt, but on track you can get the same power to the wheels with high RPM and revised gearing. :D
 
Dont think youl ever make your power goals on a bseries really.
 
High compression, fully worked head and intake runners, new cams and springs, B18C block on race fuel..may get you to 250whp; your going to need a good shop for the head work tho. as well as the tune. 2.5" exhaust too--or larger. ;)

I am on this path now.
 
We have decided what will be our setup. Kozy just confirm our thoughts. We will be using B18C block with darton sleeves with 86mm pistons, B16B crank with B16B rods. The head is going to be build in one of the best shops in our country, but before building it a friend of mine will calculate what cams, valves, etc. we will use. It will be a little slowly build because of money issues but we hope it will be ready for the 2011 track season in our country. We still have to clear what exhaust manifold to use? Also we wonder what intake will be good for this kind of setup, edelbrock, skunk, etc. or just go with ITB? Any suggestions? :win:
 
Sounds like a superb setup and would be exactly what I would be building if I had the money! Would you be willing to PM me the details on how you calculate the cams you'll be needing? I can do the valves, intake and exhaust runners/ports but calculating the required cams is something I haven't fully figured out yet.

As for intake / exhaust systems, I could not recommend brands however based on a rev limit of 10k (so assuming max power at 9500) you'll need 260.53mm long primaries on the intake system. I don't know whether you'll get an off the shelf intake manifold to that spec so ITBs might be the way to go. ITBs will give you good midrange gains too so I would definately look into them for a track/race engine.

You'll also be needing 545.26mm long primaries on the exhaust system. No idea what manufacturers make systems to this spec again so would be worth ringing round and finding out.
 
I just modelled up a basic 86mm piston and checked the mass properties against a 81mm piston and the bigger piston is around 10% heavier purely based on the increase in diameter. At the spec you are planning my BOTE math gives about a 30% increase in tensile load on the rod at TDC over the standard B16B at 8200rpm.

You want to look into the tensile strength of the stock rods/pins, they may not be up to the job if you want to rev that high!
 
Just out of interest Kozy, what program/package are you using to model the pistons?

Cheers

joe
 
Might be wrong, but when I last researched B20's ect, the max that Darton sleeve up to, is 85mm for B-series. They may have newer sleeves out I guess though. Sounds like a great setup!

As Tama said 2,5" ++ exhaust system for the extra power, I'd probably go with the ITB setup as they work well with high comp motors.
 
joe said:
Just out of interest Kozy, what program/package are you using to model the pistons?

Cheers

joe
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Pro Engineer.


Wazer said:
Might be wrong, but when I last researched B20's ect, the max that Darton sleeve up to, is 85mm for B-series.
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I thought this was the case also.
 
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Interesting build please keep us updated. I think the gearing will have a signifcant effect with such high peak rpm what plans do you have.
 
I keep researching the setup. Thanks to all for the answears to my questions. When we start the build I will keep you updated. As for the gearing when we build the engine we will test it and will calculate what change to make with the gears.
 
why do you need to rev it to 10k why not bring it down to 9 and stick with the bore and stroke you have but build that properly and like you say match with a good gearing setup?
Im sure it will be a lot less heavy on the wallet plus you will have more torque lower down than a top end screamer

all depends on your circuits too there maybe 1 track in the UK where a top end sreamer is of any use at all?
 
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