The next power levels for a stock cid n/a motor?

[rkreigh]

Originally Posted by tpepmeie

It would take about 20 more hp to truly get 600 brake hp, at STP conditions (as is normal for engine dynos). By my calculations, Pete is pushing 13.3 BMEP @ 6800 peak power speed. That is a specific output on par with the very best Tuner 415's out there (abt 560 SAE rwhp for a 415, for example).

To get much beyond that would take either 1) a further improvement in charging efficiency - breathing, or 2) drastically reduced frictional losses.

#1 would likely require something like an individual throttle tuned-length intake and more aggressive cams. #2 maybe a dry sump, low friction rings, and smaller bearing diameters.

FWIW, the Lotus GT1 race engine, unrestricted, gave about 13.5-13.6 BMEP @ 7000 RPM.

Todd

P.S., well done Pete!

man I need more porting! my 390 makes about 508 at the wheels, 617 on the "friendly" LPE engine dyno. getting that HP out of a stock block is very impressive

we talked about going with a "mini stroker" crank, with ground down rod journals to get the 396 displacement without the high billet crank cost, a much lighter rod with smaller (lower drag) bearings

I also love the individual runner idea. remember the old BB chevy "crab cross ram" lemans intakes. long tubes that gave a very straight shot at the head port. get real tricky and use a slider throttle valve for very low restriction.

doesn't make much low end torq, but screams upstairs

Pete

you have done a phenomenal job squeezing power out of the stock block

congrats on the many long hours of r&d

your heads are awesome!

[tpepmeie]

Originally Posted by LT-5 Music

Todd mentioned low friction rings, dry sump and smaller bearing diameters. What do you think about implementing those ideas for the LT5?

By that point you're already way into the bottom end, so no point in keeping it 350 cids. 4-inch liners/pistons, and you'd be closer to if not more than the 600 hp. A few years back, Bill Kirchhofer did a 368 w/ nasty cams which did 609 brake hp. It wasn't for street, and made peak power very high >7500 rpm. At that speed, the BMEP was only 12.1 bar.

Using the specific output Pete has achieved, a 368 @ 6800 rpm peak power speed would be just over 600 brake hp.

[Pete]

Originally Posted by LT-5 Music

Pete,

Thanks for taking the time to share your LT5 wealth.

To get to 600fwp streetable (and beyond?) I have some more questions if you don't mind...

What max CR do you think could be run on the street?

Based on the cam/head/intake setup you have now, do you have an estimate on much more hp/tq could be gained from the most radical cams you could run that still have decent street manners?

Do you think there is any power to be gained from further mods to the electronics on your car?

Todd mentioned low friction rings, dry sump and smaller bearing diameters. What do you think about implementing those ideas for the LT5?

Thanks,

Skip

With not having to change anything in the buttom end of the motor i don't think more compression is possible,otherwise i'm sure 12:1 should be ok.

More power from cams could be possible if i were to try i would try
.240 .475 Intakes with my.220 .425 might be worth a few horses i have noticed exhaust doesn't need to be as big as the intake.
Cam R&D gets a bit pricey if i find a bag of money in a back of a cab i'll
try it

My whole deal is how much power can a stock bottom end make.

For now i will play with cam timing.

Pete

[tpepmeie]

Originally Posted by Pete

For now i will play with cam timing.

Pete

You mean there are still cam timing settings you haven't tried?

[LT-5 Music]

Originally Posted by Pete

i'm sure 12:1 should be ok.

Cam R&D gets a bit pricey if i find a bag of money in a back of a cab i'll try it

My whole deal is how much power can a stock bottom end make.

Pete

12:1 sounds about right... thanks.

I understand you want to keep the stock bottom end.

A Pete's R&D fund might catch on here.

Skip

[Aurora40]

Originally Posted by Pete

Bob,drivability is like a stocker.
The cams don't cam that bad,remember stock cams are .229 .390 lift
mine are .236 .425lift.

Yes,i do have light flywheel DRM steel 19lbs

I guess if i install stock 1994-95 exhuast and stock flywheel i could/would loose 25-30 hp,just a guess.

Besides these 2 factors trans rattle and exhaust sound it drives like a stocker.

Pete

That's still about 450whp then, which would be stouter than some 368's! So what are the secrets, or rather why don't most "turn-key" 350ci packages from various builders make that kind of power? Is the cost vs gain of the extra porting/cams prohibitive?

Do your cams change the primary and 2ndary profiles? I would guess that if the primaries change, some people might have trouble with emissions. VA has fairly tight emissions regs and I'd guess more aggressive cams might push the limit.

Thanks for the info!

[LT-5 Music]

Originally Posted by tpepmeie

By that point you're already way into the bottom end, so no point in keeping it 350 cids.

I hear what you are saying Todd, but I would keep it at 350 cid because I like the challenge of working within the confines of the factory 350 cid.

I still believe 600 bhp is obtainable with a streetable setup.

Just my 'umble opinion.

Whether I'm right or wrong, it will be fun to see the envelope get pushed around.

[Pete]

Originally Posted by Aurora40

That's still about 450whp then, which would be stouter than some 368's! So what are the secrets, or rather why don't most "turn-key" 350ci packages from various builders make that kind of power? Is the cost vs gain of the extra porting/cams prohibitive?

Do your cams change the primary and 2ndary profiles? I would guess that if the primaries change, some people might have trouble with emissions. VA has fairly tight emissions regs and I'd guess more aggressive cams might push the limit.

Thanks for the info!

First let me say every engine is different some make more power some make less.

Let me also say some tuners are getting these #'s or close to them.
420-430rwhp they could get a few more,take secondaries out,free flow exhaust,headers (no cats),light flywheel,cam tuning,extreme chip tuning, most Z owners don't like the trans rattle,loud exhaust,want/need CATS,
they want the secondaries and smooth idle, all of these have to be worth an additional 15-20rwhp.
Add cams for an extra 20rwhp

My Intake cams are .236 primary & secondary
In IL all OBD I cars don't have emissions not too bad for a Democratic state
When funds become more available i'll try bigger cams,maybe next year.

Unless the "Pete's R&D fund" raise's enough funds then i'll try it this winter.

Pete

[LT-5 Music]

Originally Posted by Pete

Unless the "Pete's R&D fund" raise's enough funds then i'll try it this winter.

Pete

The fund could be a cost saver for those looking to avoid taking up residence on the shores of pricey Camm Lake, preferring instead to take a guided tour. Membership would have its privileges.

[Locobob]

I like the dry sump oiling idea. Be cool if someone came up with a conversion kit - no small undertaking I am sure.