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* 91 mm stroker crank for Mitsibushi Evo rod size. Nitride hardened.
* Carillo rods
* ACL race rod bearings - great upgrade with this rod/crank spec
* 968 dry sleeved block with pinned girlde and 9/16 ARP head studs
* 968 head with Lindsey beehive valve springs
* 280/268 degrees camshafts
* Custom 1 7/8" 4-1 headers in 321
* CEP dry sump system
* Short runner intake from my previous engine
* Garrett GT3582R with 1.06 a/r T3
* Custom JE pistons in 2618
Other stuff that will be reused:
* Tial 44 mm wg
* Link G4 EMS
* Bosch 1200 cc high imp injectors
* Fuellab fuel pump and filter
* Larger intercooler
etc..
What connecting rods are in this again? There was mention of the offset grind in this one. You and Chris White were talking about that with a damaged crank you had?????? Or am I imagining things too early in the morning on no sleep???? Not sure if my questions make any sense???
Put a potato in the exhaust next time, instant "mashed".
Get the time/effort/money you've sacrificed towards these motors - cars. Thanks for sharing the "sweat - equity" here. Your no longer a target - inspirational individual taking this breed much further than anyone I've known openly sharing.
G
Originally Posted by Duke
Before tearing down the engine and car to start with the changes for 2016 I took it to the dyno to test some higher boost. Results at 1.5 bar of boost:
At the crank (the dyno measures driveline losses):
767 hp / 878 Nm.
At the wheels:
676 rwhp (need to check the torque)
This 3.1l 16v turbo engine is really amazing. Peak boost of 2.0 bar on some runs and no sign of head lift or gasket leakage. As you might remember I set up production for a new type of head gasket and what can I say, this is the stuff to have!
To not muddy this great build. I'll just leave it alone.
Duke has done the most convincing (imo) interpretation of your original stroker concept. While your idea seemed originally based on optimising costs, it is clear that reducing the rotating mass with lighter rods/rod journals and using better than stock rod bearings can also lead to building some seriously high-revving race engines (Obviously with all the right supporting mods, etc). Thank you Sid, and also thanks to Shawn who has taken the time to document the concept on here.
I am just posting this so that folks who may not have followed the stroker builds since the beginning don't put credit where it's not due when reading Gruhsy's post.
Sorry hope I did't side track anything with pulling up the old post.
Originally Posted by Thom
Duke has done the most convincing (imo) interpretation of your original stroker concept. While your idea seemed originally based on optimising costs, it is clear that reducing the rotating mass with lighter rods/rod journals and using better than stock rod bearings can also lead to building some seriously high-revving race engines (Obviously with all the right supporting mods, etc). Thank you Sid, and also thanks to Shawn who has taken the time to document the concept on here.
I am just posting this so that folks who may not have followed the stroker builds since the beginning don't put credit where it's not due when reading Gruhsy's post.
This engine build started 3 years ago and has been running in the race car for 3 seasons now (with different configurations on the top end).
My previous engine (the 3.0l 16v 9.5:1 CR 514 rwhp @ 1.15 bar pump fuel engine) had a catastrophic rod bearing failure at the track about 3 years ago. The crank and block was damaged (along with other parts). I started planning the new engine and the crank was basically toast at this stage. Instead of tossing it and getting a new one I was inspired by Sid's stroker efforts and continued on that path. For those who doesn't know, offset stroking is not a new thing and has been done for ages with different types of engines and was also done in the 928 world since earlier. But Sid was as far as I know the first one to do it in a 944/968 engine and deserves credit for that.
Just to clarify - my engine is not a result of the "hybrid stroker" concept that has been successfully done by other members on this board. My engine concept and specs in regards to stroke, bore, pistons, rings, head, cams, intake manifold design, exhaust header design, turbo, engine mapping, drive train, head sealing, balance shafts etc. is something I designed myself with some input regarding the bottom end from my engine shop.
In regards to the rods - my engine shop is a big distributor for Carrillo and JE. We looked through the catalogue for suitable rods. I didn't want to go custom unless really necessary (for availability reasons). Some of the Honda rods looked good but a little small big end IIRC and would be better suited for an N/A build. The Mitsu Evo rods had suitable dimensions and the H-beams are proven 1000 hp rods. They were also in stock and with all things considered they were chosen for the build. I could tell a story for each component that was chosen for the build, why this specific bore (104.15 mm) was chosen, rod length, stroke etc. But I don't have time to write a book
It's pretty amazing how the development curve has escalated the last years and all these cool high hp builds contribute to the total wealth of knowledge.
For the sake of science it would be so damn interesting to switch to a larger turbo and raise the boost. With a larger turbo I should hit ~850 crank hp at 2.0 bar. But this is really unchartered territory so who knows how well the head combustion chamber and overall block rigidity would hold up! Maybe a fundraiser could get this ball rolling lol
I've been operating on the premise that 800crank is about the limit of the block, i have not had the spares (or the time) to test that theory. A stronger block would be nice.
I've been operating on the premise that 800crank is about the limit of the block, i have not had the spares (or the time) to test that theory. A stronger block would be nice.
It seems like a reasonable limit for a race car. I'm sure it can hold up above that level for a few dyno runs but making it last on the race track even for only 1 hotlap at the time is another thing.
A stronger block would be very nice. In some other engine families it's the combustion chamber in the head that cracks with too high cylinder pressure so it's hard to know how far a stronger block would take us.
Too bad the markets is too small. I'd be happy to develop an engine and put on an engine dyno for sustained load above 800 hp too see what fails first. But the knowledge gained would not cover the value lost.
Switching to the next frame size of turbo is a salty bill for sure, but you should not have too many problems selling your current turbo.
I will put another 100 crowns
10-30-2015, 02:26 AM
