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Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 6:30 am
by ptuomov
hoffman900 wrote:
Thu Nov 02, 2017 5:39 am
At that rpm peak, you’ll want 4 valves. If you’re not limited by rules, you’ll want 4 valves per cylinder. Makes for a much wider power band.
Plus if turbocharging a factory 4-valve head for about 4hp per CI at 7500, I think one can use mostly stock components of some popular 4-valve head platform. For example, I think that a destroked modular Ford could use well selected production heads with stock valve sizes, a production “boss” type intake manifold, etc. The main aftermarket components would be custom rotating assembly for less stroke and the selected compression.

A higher budget route would be to find a wrecked AMG car and use the MB/AMG M178 which makes over 600hp in stock form from 4L V8 with somewhat restrictive breathing into the compressors and out of the turbines. That might be a fun thing to “turn up”.

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 7:30 am
by hoffman900
Absolutely. I like the destroked Mod motor. As you said, the heads and intake would be the stock castings.

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 11:30 am
by mekilljoydammit
Actually, thinking of lower stress stuff without huge amounts of custom work... what about the import V8s? The Toyota UZ V8s are right around that displacement as are the Nissan VK V8s, both of them have been proven in motorsport. Neither has a huge aftermarket but cams are available (Kelford for the Toyota, Jim Wolf for the VK) and most anything else is doable with some ingenuity, right?

Doing some quick math, the GM 4.8 is going to need a custom crank to get below 260CI - there's not enough journal to get below about 3" stroke with any realistic rod bearings.

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 11:59 am
by jet1
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?

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 12:05 pm
by ptuomov
mekilljoydammit wrote:
Thu Nov 02, 2017 11:30 am
Actually, thinking of lower stress stuff without huge amounts of custom work... what about the import V8s? The Toyota UZ V8s are right around that displacement as are the Nissan VK V8s, both of them have been proven in motorsport. Neither has a huge aftermarket but cams are available (Kelford for the Toyota, Jim Wolf for the VK) and most anything else is doable with some ingenuity, right? Doing some quick math, the GM 4.8 is going to need a custom crank to get below 260CI - there's not enough journal to get below about 3" stroke with any realistic rod bearings.
If one wants to go in that direction, I'd consider VH41DE V8 from Infiniti Q45. That's 4.1L V8 and once could conceivably open up the combustion chamber to reduce squish and dish the piston a little bit to lower the compression ratio from stock 10.5 to something like 9. With a custom intake manifold and twin turbos, this might be a cost effective starting point. My understanding (not experience) is that the beauty about these 1990's Japanese engines is that they were so overbuilt that the stock components can usually take almost any sort of power adder, as long as compression, fuel, fueling, and ignition are within reason.

http://mywikimotors.com/vh41de/

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 12:34 pm
by In-Tech
This sounds like a marine endurance application. What about a 4.8L iron block bored to 3.900", LSA forged steel factory 3.62" crank. Get with a good balance guy and make some "fake rods" and run it as a 6 cylinder. Richard at west coast cylinder heads to do some cnc 243 heads. Block off 2 intake ports(etc) and you have cheap block, heads, crank, cam, intake manifolds, etc, etc. Turbo and intercooler and away you go 8)

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 1:22 pm
by mekilljoydammit
ptuomov wrote:
Thu Nov 02, 2017 12:05 pm
mekilljoydammit wrote:
Thu Nov 02, 2017 11:30 am
Actually, thinking of lower stress stuff without huge amounts of custom work... what about the import V8s? The Toyota UZ V8s are right around that displacement as are the Nissan VK V8s, both of them have been proven in motorsport. Neither has a huge aftermarket but cams are available (Kelford for the Toyota, Jim Wolf for the VK) and most anything else is doable with some ingenuity, right? Doing some quick math, the GM 4.8 is going to need a custom crank to get below 260CI - there's not enough journal to get below about 3" stroke with any realistic rod bearings.
If one wants to go in that direction, I'd consider VH41DE V8 from Infiniti Q45. That's 4.1L V8 and once could conceivably open up the combustion chamber to reduce squish and dish the piston a little bit to lower the compression ratio from stock 10.5 to something like 9. With a custom intake manifold and twin turbos, this might be a cost effective starting point. My understanding (not experience) is that the beauty about these 1990's Japanese engines is that they were so overbuilt that the stock components can usually take almost any sort of power adder, as long as compression, fuel, fueling, and ignition are within reason.

http://mywikimotors.com/vh41de/
On the one hand yes, and the VH was used successfully a lot of places. My personal issue would be the question of where to get cams, whereas the VK ones are off the shelf.

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 1:31 pm
by ptuomov
mekilljoydammit wrote:
Thu Nov 02, 2017 1:22 pm
ptuomov wrote:
Thu Nov 02, 2017 12:05 pm
mekilljoydammit wrote:
Thu Nov 02, 2017 11:30 am
Actually, thinking of lower stress stuff without huge amounts of custom work... what about the import V8s? The Toyota UZ V8s are right around that displacement as are the Nissan VK V8s, both of them have been proven in motorsport. Neither has a huge aftermarket but cams are available (Kelford for the Toyota, Jim Wolf for the VK) and most anything else is doable with some ingenuity, right? Doing some quick math, the GM 4.8 is going to need a custom crank to get below 260CI - there's not enough journal to get below about 3" stroke with any realistic rod bearings.
If one wants to go in that direction, I'd consider VH41DE V8 from Infiniti Q45. That's 4.1L V8 and once could conceivably open up the combustion chamber to reduce squish and dish the piston a little bit to lower the compression ratio from stock 10.5 to something like 9. With a custom intake manifold and twin turbos, this might be a cost effective starting point. My understanding (not experience) is that the beauty about these 1990's Japanese engines is that they were so overbuilt that the stock components can usually take almost any sort of power adder, as long as compression, fuel, fueling, and ignition are within reason.

http://mywikimotors.com/vh41de/
On the one hand yes, and the VH was used successfully a lot of places. My personal issue would be the question of where to get cams, whereas the VK ones are off the shelf.
A question back to you: if you can get the compression to 8.5:1, fabricate a custom single plane intake, twin turbo charge the engine with two twincscroll turbos, do you even need any other cams than the stock cams to make 1000hp at 7500rpm! ;-). It maybe VH45DE or VK45DE are better starting points, I’ve only owned one VK45DE and did nothing other to it than drive it like I stole it.

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 1:37 pm
by Erland Cox
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

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 1:39 pm
by ptuomov
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? ;-)

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 2:36 pm
by mekilljoydammit
ptuomov wrote:
Thu Nov 02, 2017 1:31 pm
A question back to you: if you can get the compression to 8.5:1, fabricate a custom single plane intake, twin turbo charge the engine with two twincscroll turbos, do you even need any other cams than the stock cams to make 1000hp at 7500rpm! ;-). It maybe VH45DE or VK45DE are better starting points, I’ve only owned one VK45DE and did nothing other to it than drive it like I stole it.
Full well admitting that I haven't dug into the engines past looking at some parts availability... my personal view is that in general, optimizing things for higher RPM and then boosting it may be less stress than keeping it stock and boosting it more. In this specific case, the stock redline is 6600rpm and not the 7500rpm looked at so that goes double... though yeah, quite possibly you could just make all of that 1000hp with a stout bottom end and boost. I figure, the VK is heavily based on the VQ V-6 which has been developed to high RPM... from all accounts there's decent head flow there, and JWT makes cams for versions that are used in professional racing so could probably advise on cams for other applications, plus I think the stock rod journals are about 2.125" so plenty of meat to offset grind to the desired displacement.

Or, well, god knows the Ford Mod Motor stuff mentioned a few posts back is well proven. :mrgreen:

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 2:48 pm
by jet1
I ran across this although I admit not real familiar with them.
http://www.superstreetonline.com/featur ... ssan-350z/

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 3:30 pm
by DaveMcLain
Ford Coyote' with slightly reduced displacement and two turbos. Those are a cool engine.

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 3:38 pm
by mekilljoydammit
The VQ is very similar to the 3.8L V6 in the GT-R - I think the GT-R version is mostly just a bit more stroke and taller deck plus detail refinements that would largely go away with aftermarket parts.

Lots of ways to skin this cat.

Re: How much power can I make from 260 CI

Posted: Thu Nov 02, 2017 3:43 pm
by CamKing
hoffman900 wrote:
Thu Nov 02, 2017 7:30 am
Absolutely. I like the destroked Mod motor. As you said, the heads and intake would be the stock castings.
Agree. A customer of mine is making 1,300hp with a 4.6L 4-valve Ford Modular