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BTW, I'm pretty sure R51 is going to be a destroked high rpm motor if my memory serves me correctly. Was it some odd number like 3.5L?
Pretty much, but it still makes more power than a Stage II track Performer 4.0 at every RPM point all the way down to 2,000 RPM. None of the factory dimensions were used for this engine, not even rod length.
New Alignment and Corner Balance with help from many here:
Wow 3,422 total weight after removing the fwd along with lightweight seats and your other mods? My 4s corner balanced at 3248 with fwd and rear seats delete 1/4 tank of fuel. Wonder why you are 174 lbs heavier? fully caged? full tank?
Pretty much, but it still makes more power than a Stage II track Performer 4.0 at every RPM point all the way down to 2,000 RPM. None of the factory dimensions were used for this engine, not even rod length.
When you say "power", are we talking HP? How's the tq curve compared to the stage2 track performer? I realize they are both meant for different duties so different characteristics for different uses, just trying to gauge the difference is all.
When you say "power", are we talking HP? How's the tq curve compared to the stage2 track performer? I realize they are both meant for different duties so different characteristics for different uses, just trying to gauge the difference is all.
More power everywhere... At some points the plots will lay over each other between the Stage II and R51, but thats it.
There's one owner who had a Stage II 3.8 and now has the R51 in the same car. He'd be the best one to explain it.
More power everywhere... At some points the plots will lay over each other between the Stage II and R51, but thats it.
There's one owner who had a Stage II 3.8 and now has the R51 in the same car. He'd be the best one to explain it.
Sorry if I wasn't clear but I was asking if the R51 has less torque essentially through out the rev band than the 4.0 stage 2 track performer.
Can you explain what kind of customer/uses would be best for R51 vs your existing stage II 3.8 or 4.0 track performer? Or do you plan on not offering the latter options any longer?
The R51 will remain at the top of the food chain. The other engines will remain the more usual choices.I would only make the R51 a more normal offering IF someone started getting close to our output for the more common engines, but thats far from happening.
Sorry if I wasn't clear but I was asking if the R51 has less torque essentially through out the rev band than the 4.0 stage 2 track performer.
No, The R51 makes the same, or more EVERYWHERE.
Forget about size differences and power, the smarter, more efficient combination will always win. Remember, I have changed piston speeds, have capitalized on swirl within the ports, and have no factory components restraints with the R51. It was a blank sheet of paper to start from.
I've even built one from a 2.5 Boxster block... Adding a liter was easy.
The sound of the R51 is insane, nothing like any other Porsche engine I have ever developed.
The R43 is the 4.3L version of the R51, it uses the same insane bore size with my largest stroke possible and is for the guys that no matter what, simply cannot get it through their skull that bigger isn;t better... You know what the real problem is? The R51 doesn't "sound big enough" to impress their friends, and thats who they are worried about.
Thanks for the explanation. Seems like the R51 is engineered really well. Using a 2.5L Boxster block is even impressive. So I'm assuming the block is strong enough or does it have to be reinforced in some way with the amount of insane bore size you are using considering that it's also high revving?
Thanks for the explanation. Seems like the R51 is engineered really well. Using a 2.5L Boxster block is even impressive. So I'm assuming the block is strong enough or does it have to be reinforced in some way with the amount of insane bore size you are using considering that it's also high revving?
Nope.. Physically it's the same as every other M96 block, except the cylinder deck is made to a smaller bore.
My highest output engine ever built was built on a 2.7 Boxster block... When it's all reconstructed, it doesn't matter what it was.... It's all machined away anyhow.
The cylinders of the R51 are completely different than any other M96 arrangement, along with their reinforcements and gussets. This even differs from my other engines, even those with bore sizes of 101.6mm.
The method of installation and mechanical locking is Patent Pending.
Last edited by Flat6 Innovations; 08-05-2016 at 07:32 PM.
Wow 3,422 total weight after removing the fwd along with lightweight seats and your other mods? My 4s corner balanced at 3248 with fwd and rear seats delete 1/4 tank of fuel. Wonder why you are 174 lbs heavier? fully caged? full tank?
This was with a full tank of gas and I'm putting on sympathy weight along with the Mrs.
First born due in a few weeks! (hopefully I'll also lose a few lbs in the process)
I'm 185 so that might be the difference as these scales include my weight in the driver seat
Last edited by vandersmith; 08-06-2016 at 05:17 AM.
The flywheel is costing you 5-7HP and 10-12# of torque moire than likely.
The scaling on those plots is wrong, or the dyno tach wasn't calibrated to the ignition signal for a 6 cylinder engine...
With these things being skewed the output can be effectuated, since Power X RPM= HP. I'd have them re- scale the plots, or re- do the tests so they properly match the RPM the engine actually saw.
Odd thing is, the TQ and HP actually cross at 5,252 RPM as they should, so thats really odd... Did the engine actually see 8,500 RPM? I don't think so!
Jake, you've seen power losses from the lighter flywheels?
Here's some track video from Friday's PCANW day at the Ridge:
Car was aligned, lowered and corner balanced at TruLine Bellevue to the GT2 Specs with new NT01s.
The car responded brilliantly but was a handful. Took an entire day to get the line dialed as the car favored much more oversteer versus the predictable throttle and push thru apex that existed with the previous alignment. Slow in fast out matters much more now as throttle application mid-turn requires much more finesse than before. Turn in was much improved. Entry, Mid, Exit speeds are all relatively the same but the car is much more lively.
I dig it and will need a few more days to adjust. Lap times we're similar 1:55s-1:56 on new NT01s that weren't broken in. They should drop a few ticks as I acclimate and they break in.
Anyway, here's the final session's video chasing a few instructors and my buddy in his 930 Turbo.
It looks like the car has too much understeer from the video. The only oversteer I saw was going from under to over mid corner. You might find it more predictable and really nice to drive if you can dial in the front end a little better. You may find yourself getting to the gas earlier (due to not battling understeer) and balancing the car more with the throttle mid corner and throughout exit.
It looks like the car has too much understeer from the video. The only oversteer I saw was going from under to over mid corner. You might find it more predictable and really nice to drive if you can dial in the front end a little better. You may find yourself getting to the gas earlier (due to not battling understeer) and balancing the car more with the throttle mid corner and throughout exit.
I think the front (C4S) sway bar is still too heavy even on its softest setting.
My front lip also decided to **** the bed mid-day and which lead to a VERY light front-end the rest of the day:
08-05-2016, 12:52 AM
