How much power can I make from 260 CI

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jet1
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Re: How much power can I make from 260 CI

Post by jet1 » Wed Nov 08, 2017 10:20 am

Charge cooler is really easy with a huge water pump already in the back of the boat vs methanol in a boat with all kinds of water around. Hopefully av gas will be enough. going to q16 is way pricey with the amount of fuel we go through.

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Re: How much power can I make from 260 CI

Post by kimosabi » Sun Nov 12, 2017 6:40 am

jet1 wrote:
Wed Nov 08, 2017 10:20 am
Charge cooler is really easy with a huge water pump already in the back of the boat vs methanol in a boat with all kinds of water around. Hopefully av gas will be enough. going to q16 is way pricey with the amount of fuel we go through.
Yeah I was thinking weight that's all. You'll easily save 25lb or more by not bolting a chargecooler in the boat. How much you pay for avgas, I assume 100LL, compared to E85. If E85 is available to you.

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Re: How much power can I make from 260 CI

Post by peejay » Sun Nov 12, 2017 9:18 am

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.
Why not debored? Sleeve a Mark VIII block down with some thickwall sleeves, gain better ring seal with your lower displacement?

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Re: How much power can I make from 260 CI

Post by jet1 » Tue Nov 14, 2017 12:25 pm

kimosabi wrote:
Sun Nov 12, 2017 6:40 am
jet1 wrote:
Wed Nov 08, 2017 10:20 am
Charge cooler is really easy with a huge water pump already in the back of the boat vs methanol in a boat with all kinds of water around. Hopefully av gas will be enough. going to q16 is way pricey with the amount of fuel we go through.
Yeah I was thinking weight that's all. You'll easily save 25lb or more by not bolting a chargecooler in the boat. How much you pay for avgas, I assume 100LL, compared to E85. If E85 is available to you.
E85 is not available around here at the present time. Av 100ll runs me about $1.75 litre.

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Re: How much power can I make from 260 CI

Post by jet1 » Tue Nov 14, 2017 12:29 pm

peejay wrote:
Sun Nov 12, 2017 9:18 am
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.
Why not debored? Sleeve a Mark VIII block down with some thickwall sleeves, gain better ring seal with your lower displacement?
Thats about were I am at only with an LS motor. Use some Darton dry sleeves and bring the bore down on an LS3.

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Re: How much power can I make from 260 CI

Post by englertracing » Tue Nov 14, 2017 1:37 pm

peejay wrote:
Sun Nov 12, 2017 9:18 am
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.
Why not debored? Sleeve a Mark VIII block down with some thickwall sleeves, gain better ring seal with your lower displacement?
Because big bore short stroke....

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Re: How much power can I make from 260 CI

Post by peejay » Tue Nov 14, 2017 7:24 pm

But boost. RPM spec is only 7500, no need to play bore/stroke games at speeds that low. Block integrity would seem to me to be more important.

Plus, I keep hearing that thin cylinders cause thermal issues from blowby, so having nice thick cylinder walls would be a boon to keeping temperatures properly controlled.

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Re: How much power can I make from 260 CI

Post by ptuomov » Wed Nov 15, 2017 8:23 am

peejay wrote:
Tue Nov 14, 2017 7:24 pm
But boost. RPM spec is only 7500, no need to play bore/stroke games at speeds that low. Block integrity would seem to me to be more important. Plus, I keep hearing that thin cylinders cause thermal issues from blowby, so having nice thick cylinder walls would be a boon to keeping temperatures properly controlled.
The modular Ford with its DOHC valvetrain would run at 7500 rpm with no issues for the next forever.

If the block can be sleeved reliably to be smaller bore, in a turbo motor small bore will work out great. One can give more boost at the same geometric compression ratio because the combustion chamber is more compact. 86.2mm bore and custom pistons on a four-valve modular Ford with completely standard valvetrain would probably fit and run at 7500 rpm with now issue, but mod Ford experts should chime in. Would the combustion chambers need to be welded for a good chamber shape, or does the stock chamber look good with 2mm shift in the bore wall inwards? Factory crankshaft, too, would that work? From the turbo perspective, one could boost the sweet bejezus out of it. That's close to Mitsubishi Evo bores and those engines appear to burn very well.
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Re: How much power can I make from 260 CI

Post by jet1 » Thu Feb 01, 2018 3:24 pm

i have decided on what engine package I will be building. For a bunch of reasons it will be an LS build. I can use a stk 5.3 or 4.8 block and keep the bore below 3.9 but close to it.. Scat will build me a custom crank with a 2.7 inch stroke but I am trying to figure out a rod for it. I pretty much can go with what ever I want as the crank a pistons will custom. The rod will have to be a bit long to keep the pin high enough in the piston. Carrilo and Callies make a 6.350 for an LS which would give me 1.540 comp height which is still a bit long but one for a Nissan GTR are 6.460 which would put me at 1.430. really in the the reason I am posting is to get input on what the experts on here think would work best.

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Re: How much power can I make from 260 CI

Post by wwmtlineman » Thu Feb 01, 2018 4:35 pm

A look at the SCTA Bonneville records in the E and E blown classes will give you some idea, a lot, only limited by the size of your bank account

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Re: How much power can I make from 260 CI

Post by Keith Morganstein » Thu Feb 01, 2018 6:09 pm

DaveMcLain wrote:
Wed Nov 01, 2017 1:12 pm
Yes its possible. Smokey Yunick made 1000 horsepower from a 209 inch Chevy V8 for Indy in about 1970.
Smokey campaigned that twin turbo SBC at the Indy 500 in 1972, 73 & 75

3.875” bore x 2.2” stroke for approx 208”. The bore was sleeved smaller.

1000 Hp in race tune, Smokey claimed 1300HP on the dyno.

It didn’t complete any races (burning pistons) but engine management was primitive at best.


The LS at 3.800” X 2.85 for 258.5 Cu/In should have no problem making the power.

I think it will need piston coolers, the best parts and great engine management, maybe an aftermarket block for endurance.
Automotive Machining, cylinder head rebuilding, engine building. Old school shop, semi-retired moonlighter. Can't seem to quit #-o

jet1
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Re: How much power can I make from 260 CI

Post by jet1 » Thu Feb 01, 2018 6:28 pm

it will have piston squatters for sure. I am toying with using the GM lsx block as it would have 6 head bolts per cylinder and is alot cheaper than an after market block. I have been told many times that the stk 5.3/4.8 block would handle it easily with such a short stroke though.
I actually have a friend that holds the record for his class right now with a 260 ci sbf. 4.050 x 2.5 stroke with a 5.3 rod on a 302 block. His application is a lot different so a lot of what he has done doesn't apply.

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Re: How much power can I make from 260 CI

Post by Turborick » Thu Feb 01, 2018 8:31 pm

We are making 1000hp with a 4.0 x 2.5 SBC with a single turbo @ about 20psi.
hope to end up making 1500hp with 30+ psi
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Re: How much power can I make from 260 CI

Post by ptuomov » Fri Feb 02, 2018 12:20 pm

Are you planning to do a big single turbo, two single scrolls, or two twin scrolls? Big single with long-tube headers feeding it might not be a terrible idea. With short exhaust manifolds you'd probably want two twin scroll turbos.
[b]Paradigms often shift without the clutch[/b] -- [url]https://www.youtube.com/watch?v=cxn-LxwsrnU[/url]

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Re: How much power can I make from 260 CI

Post by jet1 » Fri Feb 02, 2018 2:54 pm

Actually I am planning on a Vortech v30-102 or a 105 unit.

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