Page 3 of 5

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 3:56 pm
by jet1
I think it will boil down to cost and availability. The Coyote motor ya for sure that would be awesome but getting one cheap then doing the mods would start getting me close to the 4 rotor. The Ford mod motor could be a possibility other than they are huge and pretty heavy. The VQ35 looks to be pretty cheap to find and fairly easy to put some good sleeves in to get some displacement plus being compact and light weight looks pretty good. The GM LS 4.8 is the cheapest and I am most familiar with it but without a 4 valve head boost is going to get up stressing the motor more. Not sure if it would live.

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 4:02 pm
by In-Tech
Boost is just a restriction of air flow. Within reason, the stress is how much hp(cyl pressure) you make, rpm and of course the tune.

It was just a thought :wink:

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 4:30 pm
by jet1
Agreed although in a turbo application the extra restriction also keeps extra heat and pressure in the exhaust side of the engine.
weights that I have found(not verified)
VQ35DE 313lb
Lq4 550lb
mod 4.6 550lb
2jz 500 lb

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 4:46 pm
by DaveMcLain
jet1 wrote:
Thu Nov 02, 2017 3:56 pm
I think it will boil down to cost and availability. The Coyote motor ya for sure that would be awesome but getting one cheap then doing the mods would start getting me close to the 4 rotor. The Ford mod motor could be a possibility other than they are huge and pretty heavy. The VQ35 looks to be pretty cheap to find and fairly easy to put some good sleeves in to get some displacement plus being compact and light weight looks pretty good. The GM LS 4.8 is the cheapest and I am most familiar with it but without a 4 valve head boost is going to get up stressing the motor more. Not sure if it would live.
I'm not sure on the weight of the two cam 4.6 mod engine but the aluminum blocks are pretty light. The packaging is huge that's for sure. Whenever I have one here on the engine stand it seems like there's always somebody asking, "how big of an engine is that?"!!

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 6:36 pm
by cjperformance
DaveMcLain wrote:
Thu Nov 02, 2017 4:46 pm
jet1 wrote:
Thu Nov 02, 2017 3:56 pm
I think it will boil down to cost and availability. The Coyote motor ya for sure that would be awesome but getting one cheap then doing the mods would start getting me close to the 4 rotor. The Ford mod motor could be a possibility other than they are huge and pretty heavy. The VQ35 looks to be pretty cheap to find and fairly easy to put some good sleeves in to get some displacement plus being compact and light weight looks pretty good. The GM LS 4.8 is the cheapest and I am most familiar with it but without a 4 valve head boost is going to get up stressing the motor more. Not sure if it would live.
I'm not sure on the weight of the two cam 4.6 mod engine but the aluminum blocks are pretty light. The packaging is huge that's for sure. Whenever I have one here on the engine stand it seems like there's always somebody asking, "how big of an engine is that?"!!
Yea the 4.6 on a stand next to a BFF 460 makes the 4.6 look like the BB of the two!

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 6:41 pm
by Erland Cox
ptuomov wrote:
Thu Nov 02, 2017 1:39 pm
Erland Cox wrote:
Thu Nov 02, 2017 1:37 pm
2,8 liter Volvo 4 cylinder 8V.

https://www.youtube.com/watch?v=BknG6yT7cho

3 liter Volvo 16 valve.

https://www.youtube.com/watch?v=cKv6_zPfDkY

Erland
How’d those run at peak power for 45 minutes? ;-)
Hot. I asked if it was for drag racing.

Erland

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 8:15 pm
by kimosabi
jet1 wrote:
Thu Nov 02, 2017 11:59 am
The application is extreme endurance. runs at WOT for periods of up to 45 minutes. Cooling and intercooling is not an issue with a constant supply of cold water.
I agree that the rotary probably is pretty expensive and alot of boost would be required to get to 1000 hp. Same with the 2jz. The ls 4.8 interests me the most and parts and pieces are easy to get and are relatively cheap I also looked at the Ford mod motor but the weight starts to add up on them pretty quick. The Nissan engine looked good other than getting parts for it. So I guess I am kinda answering my own question a bit.

Now other than the block and engine covers when using the 4.8 lS what heads would work with such a small bore and displacement? Also when running a pushrod V8 7500 rpm sustained rpm may be a little on the high side. Thoughts?
You're boating! I like the Ford mod as well but for a simpler K.I.S.S approach I'd still go LS. 7500rpm sustained rpm is not a problem with good valvetrain geometry and I'd think about flooding the valvecovers as well for peace of mind. Valvetrain will get tested hard with forced induction, loads and sustained rpm in a boat at that power level with only 260ci. As far as weight go I'd do the numbers on a single turbo vs a set of twins, single turbo probably lighter.

Sounds like a fun project!

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 8:19 pm
by ptuomov
Erland Cox wrote:
Thu Nov 02, 2017 6:41 pm
Hot. I asked if it was for drag racing.
Erland
Which was the best question of the thread!

Re: How much power can I make from 260 CI

Posted: Fri Nov 03, 2017 8:11 am
by ptuomov
Here’s a bigger boat engine that’s pretty much state of the art:
D07C00F0-5C11-4DCF-96B3-51A40B694691.jpeg
You can destroked a cheap 4-valve modular Ford 4.6L to do almost exactly the same engine, just half the displacement. Stick one of those Cobra or Boss intake on it. And notice how the Mercury engine has two cylinders paired together feeding a turbo scroll per pair. This eliminates both 180 and 90 degree exhaust blowdown interference so you can run it with whatever rpms you like and with whatever cams you like.

Re: How much power can I make from 260 CI

Posted: Fri Nov 03, 2017 10:44 am
by jet1
Yes it is endurance boat racing using a jet not a prop. WE have had one person run the QC4 mercury racing engine without issues other than the massive weight. Considering that the class it had to go into pitted it against 1800 hp t58 turbines weighing 400 lbs it had an uphill climb.

Re: How much power can I make from 260 CI

Posted: Fri Nov 03, 2017 10:52 am
by ptuomov
From the inter-webs:
When I built a 99 Cobra engine I had a chance to weigh the parts up on a 400 lbs shipping scale.
Complete 32V heads with cams - 62.5 lbs. each
Short block (aluminum block, crank, rods and pistons) - 154 lbs.
99 Cobra intake with throttle body and fuel rails - 31.5 lbs.
Assembled short block with heads, oil pan, timing cover, water pump and stock flywheel - 369 lbs.
That makes a long block about 400 lbs. without exhaust manifolds.
Alternator - 13.5 lbs.
Power steering pump with pulley - 7 lbs.
A/C compressor - 15 lbs.
Stock flywheel - 21 lbs.

Re: How much power can I make from 260 CI

Posted: Sat Nov 04, 2017 5:03 am
by kimosabi
jet1 wrote:
Fri Nov 03, 2017 10:44 am
Yes it is endurance boat racing using a jet not a prop. WE have had one person run the QC4 mercury racing engine without issues other than the massive weight. Considering that the class it had to go into pitted it against 1800 hp t58 turbines weighing 400 lbs it had an uphill climb.
Twin turbo LS 4.8 destroked to 4.25. Hands down the most cost, reliability and weight effective approach you have. That size engine is a real good twin turbo platform IMHO especially using jets as they don't hug the water like a prop does. What's the weight and length of the boat BTW?

Re: How much power can I make from 260 CI

Posted: Mon Nov 06, 2017 11:44 am
by jet1
21 feet approx 1750 lb with a cast iron LS in it no fuel. so no motor approx 1150 lbs.

Re: How much power can I make from 260 CI

Posted: Mon Nov 06, 2017 12:44 pm
by tt 383
Build it from an aluminum 5.3. same bore, cost more but weight problem solved...

Re: How much power can I make from 260 CI

Posted: Mon Nov 06, 2017 12:44 pm
by Curtis Mc
Just throwing it out there as an honest question to those who know or have first hand experience - will a stock 4.8 block survive 800-1000hp in a high load endurance application? Seems like based on the situation this engine is expected to live in, an LSX block (if that's your direction) would make sense.

A lot of good roundy-round, drag, pulling, and road race experience on this board, but this is a bit of a different animal.