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
What camshaft spec for FI 1776
- Chip Birks
- Posts: 4003
- Joined: Wed Mar 12, 2008 5:59 pm
Re: What camshaft spec for FI 1776
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 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
-
- Posts: 41
- Joined: Sat Dec 13, 2014 1:01 pm
Re: What camshaft spec for FI 1776
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.
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.
- Marc
- Moderator
- Posts: 23741
- Joined: Thu May 23, 2002 12:01 am
Re: What camshaft spec for FI 1776
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.
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.