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Thinking of a new cam...

66gt350

66gt350

Active Member
I'm thinking of re-camming my fastback. I'm not that happy with the Ford Motorsport E303 cam. Trying to get the efi tuned is becoming very frustrating. Ok here's a quick rundown of my setup:

engine out of a '89GT
bored .030 over
flattop pistons
Twisted Wedge heads
IIRC, I'm running about 9.5:1 compression
Holley Sytemmax II intake
Accufab 70mm throttle body
24 lb. injectors with pro-flow mass air meter. (I do have 30 lb injectors, if needed)
tko 5-speed
3:50 rear end

As I stated, I'm currently running the E303 cam. Here's the specs:
E303
duration 282 Intake & Exhaust
duration 220 @ 0.050 Intake & Exhaust
lift .498/.498 Intake & Exhaust
110 centerline

I've called Clay Smith Cams and Comp Cams for they're recommendation. Here's what they recommended:

Clay Smith
HR280-12-CFR - part number
duration 280 Intake & Exhaust
duration 230 @ 0.050 Intake & Exhaust
lift .512/.512 Intake & Exhaust
112 centerline

COMP Cams Xtreme Energy Camshafts
35-349-8 - part number
duration 264 Intake
duration 270 Exhaust
duration 212 @ 0.050 Intake
duration 218 @ 0.050 Exhaust
lift .512/.512 Intake & Exhaust
114 centerline

This is my daily driver, so I'm not looking for more power. I can already light the tires up easy. I'm looking for a nice cam that will cruise nicely to get me back and forth to work...but still have a little fun with the ricers when needed!!

Any opinion?
thanks
 
112 is the LCA limit for fuel injection. Here's some info...........also can you change your fuel and spark maps?

Camshaft Profile
Cam profile theory (in total) is beyond the scope of this guide but a few key concepts are important to understand
when tuning a fuel injected engine. Valve Overlap
 
I have a buttit racing cam in my car. They are very knowledgeable and great to work with. You might want to give them a call as well.
 
Re: Re: Thinking of a new cam...

Thanks for the info, but did something get cut off at the end?

"67 evil eleanor" said:
112 is the LCA limit for fuel injection. Here's some info...........also can you change your fuel and spark maps?

Camshaft Profile
Cam profile theory (in total) is beyond the scope of this guide but a few key concepts are important to understand
when tuning a fuel injected engine. Valve Overlap
Click to expand...

Sent from my XT912 using Tapatalk 2
 
"66gt350" said:
Thanks for the info, but did something get cut off at the end?

Sent from my XT912 using Tapatalk 2
Click to expand...

Nah, just normal Evil, trailing off during his thoughts :roll There is absolutely NO problems with cut-n-paste.




Zero...ever.
 
"dodgestang" said:
...obviously there is something wrong with you.
Click to expand...

You guys are just realizing that now!?!

Ok, I just got off the phone with Bullet cams and here's what he recommended:

Bullet cams
custom grind
duration 284 Intake
duration 292 Exhaust
duration 218 @ 0.050 Intake
duration 226 @ 0.050 Exhaust
lift .525/.525 Intake & Exhaust
112 centerline with 4 degress of advance built in

Decisions...decisions...decisions....
 
What the numbers don't tell you is the ramp angles of the lobes and such. That is where much of the "magic" happens and why I decided to go custom.
 
Sorry, C&P not workie well......
In short, if the cam is too radical then the EFI system will stay confused. These are extremely difficult to tune. On a radical cam the air is being bounced back and forth due to the valve timing being very close on their cycle (both intake and exhaust). This is what confuses the computer (ecm). Think of it like this, if the signals being sent to the ecm from the sensors are smooth, then the computer calculations being sent to the engine will also be smooth. On the flip, if the signals from the sensors are "all over the place" then the signals being sent to the engine will also be all over the place and the engine will run very rough. The EFI signals move at the speed of light and the engine is always trying to catch up. Some aftermarket systems will allow you to "smooth" this but on a stock ecm you are stuck with what ever is in the box. I'd suggest if you don't have the ability to "tune" the ecm (adjust the fuel and spark maps) you add that ability. If you are using a EEC-IV then a tweecer can be had for less than 300-500 bucks. That way when you change cams or add other power adders you can tune the ecm to "react" correctly to what ever you add. Again the cam shaft is the "most critical element" in the whole selection process when using efi.
 
Thanks for the info. I do have a Tweecer attached to the computer. And that has helped alot. The E303 cam is notorious for having issues. I have gotten rid of the dreaded idle surge, so I'm not stalling at stoplight and signs anymore. I've been tweaking and tweaking to several of the scalars, tables, and functions...but there are some issues that I just can't get the tune correct.

Time to hit one of the my homebrew kegs and start drinking excessively!!
 
I'd loose the cam. Anyway my favorite efi choice has a turbo or s/c. That way you have the best of both worlds.
 
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