Best cylinders for small bore turbo

[edbaus]

I am working on a 2.15 L turbo project for racing.

What is the best cylinders for this project. Should they be the steel sleeve 2L bored over from 80 to 83. All steel cylinders bored over to 83.

I want to use the 2.7L heads. But can the early 2.0 cylinders be trepaned to accept the later head sealing rings that were used with the 2.7L heads.

Thanks

Ed

[YTNUKLR]

Do you mean is it better to use an Iron cylinder or an Iron cylinder/aluminum fins? Aluminum fins--much better conduction of heat.

The 2.0 cyls can be used with 2.7 heads.

[edbaus]

Do the 2.0 cylinders get cut for the rings?

Ed

[kenikh]

I believe Biral have a heat soak point of about 200HP. If you are going to build a turbo, Nickies are the best way to go: more fins, all aluminum, Nickasil walls. YTNUKLR can tell you more detailed info about them than I can.

[edbaus]

Steve at Rennsport spoke of building a motor for this class that used a steel lined cylinders on a 2.8L. This motor made great hp. 350 Hp range. (non-turbo)

What makes the steel lined cylinders that he used different from the stock Biral cylinders.

Thanks

Ed

[strokher racing]

I would give Charles a shout at LNengineering.com he offers awesome cylinders. You can buy them right here on Pelican.

Eric Hood

[YTNUKLR]

Cost no object, which is not how I usually think, Nickies by Charles at LN are "IT".

[edbaus]

OK, let us say for a moment that cost is an object. A very large object and $2600 is a nice sized chunk of my budget.

What I would like to know is what is the next best thing.

Thanks

Ed

[kenikh]

Mahle Nikasil, which don't come in your size.

[KobaltBlau]

Originally posted by edbaus

What I would like to know is what is the next best thing.

biral with fire rings I would think; the cylinders steve is talking about are aluminum cylinders that have been bored and inserted with a steel sleve. these can be made with steel thicknesses of all measurements, I wouldn't be surprised if they cost close to what nickes do, though.

[Tyson Schmidt]

What case are you using? Hopefully it's an early aluminum case. Or an early Turbo/3.0 Carrera case.

Is there any reason you can't use 2.2/2.4 (84mm) biral cyls? Is there a 2.15 limit with the turbo multiplier?

[KobaltBlau]

Originally posted by Tyson Schmidt
Is there any reason you can't use 2.2/2.4 (84mm) biral cyls? Is there a 2.15 limit with the turbo multiplier?

multiplier is 1.3 for turbo and class is 2.8, so yes that makes a 2.15 limit.

I think what some people are doing is offset grinding the crank a little with custom rods so they can use 84mm cylinders and get under 2154cc. if you could offset grind the crank down to 64.75 stroke you'd be ok with 84mm cyls: 2153cc!

[KobaltBlau]

of course the other alternative would be keeping the 66 crank and boring the 2L birals up to 83mm = 2142, which would remove the (geometrical) need for custom rods, and you're going to need custom pistons in any case. not sure if that would make the iron too thin for a turbo motor in the 2L birals, though. how thick is the iron in 2L birals?

[edbaus]

Yes,

That is a concern. What is the thickness of the biral sleeve.

Another option is to have the 84mm cylinder spray welded up to bore out to 83mm.

Also, after boring the 80mm cylinder to 83mm, is there enough room to machine in the ring for the head seal.

Thanks

Ed

[Tyson Schmidt]

Still don't know what case you are using. I'll assume it's an early aluminum case.

If it's an early Turbo/3.0 Carrera case, then you could sleeve some Aluminum barrels.

[edbaus]

Yes, early allum.

Ed

[cnavarro]

If price were an option, I would stick to an 80mm or 80.50 or 81mm overbore of a 100% cast iron cylinder, no sleeving. Wall thickness will be the only thing providing you some level of thermal stability. Also have the cylinders cryogenically treated- that will help them stay round longer, but remember at the horsepower you'll be generating, the cylinders will be toast in short order. It will hold up better than the birals when pushing the envelope. When you heat soak a biral, very bad things happen- ask anyone with birals from a 356. Also most definately you will want to run a forged piston and coat the skirts, ring lands, and crowns. The more heat you can keep out of the pistons and cylinders, the better. Personally I would leave the chambers on the heads uncoated so that the heats path of least resistance is to the heads, not the cylinders. Also, you should consider step cutting the heads and run a zero deck- it's a trick used by guys trying to keep big bore type fours together when running cast iron cylinders- although not a solution, it's a good band-aid for the problem for a short term solution.

[KobaltBlau]

Charles, you are very professional to not plug your product, but do you have some nickies that you think would not be "toast in short order" like the cast iron ones? I imagine so...

Ed, Walt Fricke mentioned that he was considering building an engine like this, I believe for the same class you are. He decided that he did not have the budget for it. This type of engine strikes me as one that needs a lot of "development work". Of couse you could buy a package from pat williams or a couple of other people but I'm sure that wouldn't be cheap!

I will be very interested to see if PCA changes their turbo multiplier. 1.3 is pretty liberal. This is in the 2006 proposed rule changes:

PCA
Rule changes recommended for comment
...
Revamp the GT classes by using a weight and displacement formula. Other considerations may include the turbo multiplier and the capabilities of water cooled versus air cooled engines. This would be accomplished by a special committee that would evaluate all of the factors and make recommendations to be implemented for 2007.

sounds like a warning about the turbo multiplier to me.

[edbaus]

Andy,

Thanks for your input.

I have spoken with Walt several times on this subject including in person at Watkins Glen. I do understand the costs involved as with any race motor. Walt's concern was more with ongoing costs rather than initial investment. He is suprised and glad for those who have the motors and how they have held up well.

The rule changes do not concern me. I think that gt3 will still be competitve if the current turbo cars are moved up as well. This proposed change has been on the books for a while.

If they really wanted to do something they would figure out how to relate Hp to weight as NASA does on their GTS serries and class the cars in that fasion.

As far as development, I expect that the work I have done with my 'street' 79 turbo will lend itself nicely to the racer. Yes the motor is larger and the cylinders are different, but my street car has been converted to twin turbos, has a custom made intercooler feeding a carrera intake and being controled by an electromotive twin plug system. All of this done by yours truly.

And on that subject. What is my alternative. Build a big 2.8L using just of expensive parts I still will not yeild the same hp as the guys running motors that cost $30k. I do not have that kind of money.

Option 3, stop racing? I have to do something and I am having fun doing this.

Thanks

Ed

[cnavarro]

Pat Williams also came to mind with small displacement turbo engines. I have done significant underbores for really big boost engines, but never for a 2L, although I do have those cylinders in Nickies form. I would almost prefer to take a 2.2/2.4 cylinder and underbore it to 80 or so mm. That would allow you to omit the silly factory sealing "gasket" from the 2.0 and give you enough real estate on the face of the sealing surface for a flame ring. Would such a cylinder be legal?- that's my only question. It seems like a 92mm or 93mm underbore of the 95mm 930 cylinder is the most popular (and the thickest cylinder I have ever made by far).