What camshaft spec for FI 1776

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paullanzarotti
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Joined: Sat Dec 13, 2014 4:01 pm

What camshaft spec for FI 1776

Post by paullanzarotti » Wed Sep 14, 2016 11:40 am

I am planning my engine build which is going to be fairly mild because I want to keep stock heat exchangers. One area that I am not sure about is cam specs because I am using a Mexican FI set up with programmable ECU (Megasquirt). I understand that with FI engines it's a good idea to keep the cam mild. t the same time I am going to be using Hydraulic lifters because I'm lazy and would rather not have to deal with leaky rocker covers after adjusting tappets every 6000 miles.

I would like to have power throughout the RPM range with RPMS going to around 5500-5800 if possible.

Engine spec is as follows:
90.5 P&B
8:1 Compression
Heads 37x32 - polished and ported
Exhaust 35mm Merged
Crankshaft DRP Balanced
Solid Rockershafts 1:1
Hydraulic Lifters (Either Mofoco or Type 4)
Mexican FI - programmable
Wasted Spark Ignition
Camshaft ??????

I'm thinking a 280 X 420 would probably do it but interested to get suggestions.

Thanks

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Chip Birks
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Joined: Wed Mar 12, 2008 7:59 pm
Location: Pleasant Grove, Utah

Re: What camshaft spec for FI 1776

Post by Chip Birks » Wed Sep 14, 2016 12:35 pm

paullanzarotti wrote:I am planning my engine build which is going to be fairly mild because I want to keep stock heat exchangers. One area that I am not sure about is cam specs because I am using a Mexican FI set up with programmable ECU (Megasquirt). I understand that with FI engines it's a good idea to keep the cam mild. t the same time I am going to be using Hydraulic lifters because I'm lazy and would rather not have to deal with leaky rocker covers after adjusting tappets every 6000 miles.

I would like to have power throughout the RPM range with RPMS going to around 5500-5800 if possible.

Engine spec is as follows:
90.5 P&B
8:1 Compression
Heads 37x32 - polished and ported
Exhaust 35mm Merged
Crankshaft DRP Balanced
Solid Rockershafts 1:1
Hydraulic Lifters (Either Mofoco or Type 4)
Mexican FI - programmable
Wasted Spark Ignition
Camshaft ??????

I'm thinking a 280 X 420 would probably do it but interested to get suggestions.

Thanks
You can run what ever cam you want with programmable FI, I've run from fairly mild to pretty wild. Just requires tuning a little differently. Systems like d-jet or l-jet require mild cams if they allow for much change at all.

paullanzarotti
Posts: 37
Joined: Sat Dec 13, 2014 4:01 pm

Re: What camshaft spec for FI 1776

Post by paullanzarotti » Wed Sep 14, 2016 2:28 pm

Ok great, that's good to know.

What cam would you recommend for this set up? The car is a daily driver and I'd like to try and hit the sweet spot between performance and reliability.

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Marc
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Re: What camshaft spec for FI 1776

Post by Marc » Wed Sep 14, 2016 2:57 pm

I presume your rockers are 1.1:1, not 1:1 as stated.

The requirement to use hydraulic lifters limits the cam choices (unless you want to be brave and see how well/long a solid-lifter grind works with them). You're at risk of collapsing the lifters, and it's said that if you use hydraulic lifters on a cam designed for solid lifters, the power curve will tend to move up a bit but there will also be an overall loss of power and torque compared to what the cam would normally deliver with solid lifters.

CBPerformance's "Eagle" 2253 is a hydraulic grind with an advertised duration of 298°, but the effective (@.050") is given as 242°- around what you'd expect from a solid-liftercam with 280° advertised...must have some long clearance ramps, or maybe their measuring technique includes quite a bit of lifter travel. Their biggest grind, the 2254, has an advertised duration of 308° but they claim only 236° @.050" - something doesn't jibe there.

Lift on the 2253 is just .324" at the lobe, which'd be ~.356" with 1.1:1 rockers.
1.25s would get it over .400" but they make no claim for compatibility with those (probably less risky than using a solid-lifter cam, though). HD single springs & stronger pushrods required.

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