333pg333

Going to stick with the GTX35 for the time being. I know that normally this is considered too large for our 2.5L 8vs but this engine will clearly be different. We will be boosting this around 25psi I would guess. Maybe more. Want to see similar peak hp as the last motor.

reno808

Patrick are you going to use the auto tensioners ?

blade7

Any reason to choose CP pistons ahead of Mahle or Wossner . Are CP easier to deal with ?

333pg333

Carlos, this n/a block has been converted to the late model tensioner.


It was just convenient as the builder's shop is near these guys office. Pankl which CP and Carrillo are under the roof of. He worked with them on the design or more specifically, he gave them his design and requested that they use a different forging. It's a different looking piston to the norm. With the 16v project we'll be using Mahle pistons and Arrow rods.

As good as the flow numbers are for this 8v head, Neil flowed the stock 16v head and it came up with approx 350cfm. Look forward to seeing what the modded 16v race head comes up with. Amazing how good the stock head works and from what I've seen is superior to many modified 16v heads made for different marques.

blade7

Will you be machining windage ports into the block. Are they dry sleeves ?

333pg333

Yes dry sleeves. Haven't seen block but I don't think any windage ports. With piston squirters and dry sump plus better bearings, there's not necessarily the need. I'll know soon as some pics will be sent in the next day or two.

blade7

Thanks for the info, glad to hear dry liners are still an option. Don't you have a 2.5 16v head ?

mikey_audiogeek

Are you turboing your NA?

333pg333

That was an initial idea to use the 16v head that fits the 2.5ltr block. I was fortunate enough to have the choice between a worked 8v and 16v that would fit this customised block. Because it was, and still is, my intention to finish off the pre-existing 16v project, and also it was going to be easier and cheaper to use the existing intake and exhaust without having to make new flanges for a 16v head.

However we were also going to sort of 'throw' this motor together using stock turbo rods/pistons just to keep it cheap, but upon reflection I thought for the sake of the relatively minor cost of pistons and rods we may as well order some new ones and allow this little 8v motor to reach it's potential. Then, as is want to happen, it was decided to customise the pistons and rods to make them lighter and better balanced and I've also decided to make a new intake to suit. Interestingly on the intake, I initially thought we'd want something with much shorter runners but it appears that running specs through some software programs and working off 3rd tier harmonics that we're actually going to run longer runners than our existing. That's dependent on packaging and clearance issues though. If we can't make that fit (re: turbo clearance) then we might have to go back to some shorter runners based on the 2nd tier harmonics. Problem with that will be clearing the cooling core ducting. Fun stuff!


Ha...already done that once before Mikey. Worked fine.

ehall

Good luck on this one. I'm pulling for ya!

Dubai944

Patrick, I really admire your stamina for R&D. You must have a warehouse full of engine parts by now!

blade7

Interesting stuff about the inlet manifold. A variable length inlet could be the next step ?

333pg333

Thanks E. It should be interesting.

I'm a legitimate fool who has escaped the Asylum!

I think with a race car usually above say 4500rpm we may not need that....but you never say never!

turbotim3

Patrick, CP for me is going to be the best bet, we use them in all our big engines and have had very good results. You should ask CP about there x-forge piston which as been developed from the drag racing seen, which is the design we use.

333pg333

Tim, our builder has a pretty good relationship with CP and had to twist their arm to make changes and use a different forging than they normally offer. I don't know if it's the X forging but he said it wasn't the 4032 he normally specifies. We paid to expedite these parts and they've come through very quickly. I'm actually look forward to seeing how this motor works out.