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454 tech questions... got another, got more ?'s post 17
- Thread starter POORBOYK5
- Start date
OK, First off, I wanna thank Scott, Rene, Ryoken and anyone else who has chimed in on this thread. I put my "salvage yard" $200 454 in today and it was crap.. spun or non existant bearing. I'm done screwing around nickel and diming, its time to get serious about my "good" 454.
As for being a basic tbi guy, I'm pretty good, I understand all the parts to a TBI system. As for being at all advanced in the subject, definatly not.
So I know you all say to run a "tbi friendly cam" in my "good" 454 (88 454 crusader marine, carb'd). I have the Edelbrock Tbi intake etc...
I have the "crusader" book. the cam specs are as follows INTAKE Lift: .2694 duration: 289' EXHAUST Lift: .2804 Duration 302'. Really? 302 deg of exhaust duration?? seems odd, but I'm no expert.
The replacement "TBI" cam I bought has specs of: Intake Lift: .234 dur. 193' Exhaust .252 dur 203' Seems waaay smaller in all aspects.
Question is what makes a cam TBI friendly? I'd like to keep some Power. This motor really moved in my old sub. Excellent power range. Can the TBI not keep up fuel delivery? Not enough air flow?
I'm trying to understand what makes this stuff jive.... thanks guys!
As for being a basic tbi guy, I'm pretty good, I understand all the parts to a TBI system. As for being at all advanced in the subject, definatly not.
So I know you all say to run a "tbi friendly cam" in my "good" 454 (88 454 crusader marine, carb'd). I have the Edelbrock Tbi intake etc...
I have the "crusader" book. the cam specs are as follows INTAKE Lift: .2694 duration: 289' EXHAUST Lift: .2804 Duration 302'. Really? 302 deg of exhaust duration?? seems odd, but I'm no expert.
The replacement "TBI" cam I bought has specs of: Intake Lift: .234 dur. 193' Exhaust .252 dur 203' Seems waaay smaller in all aspects.
Question is what makes a cam TBI friendly? I'd like to keep some Power. This motor really moved in my old sub. Excellent power range. Can the TBI not keep up fuel delivery? Not enough air flow?
I'm trying to understand what makes this stuff jive.... thanks guys!
As far as I understand it overlap gives the computer fits. Most FI cams have more LSA than other cams...like in the 112-114 degree range.
Sucks about the JY 454 you got. At least it's a good core so you're not about to lose money on it.
Rene
Sucks about the JY 454 you got. At least it's a good core so you're not about to lose money on it.
Rene
Ok, keep in mind the cam specs you posted are for LOBE lift so you need to multiply that by the rocker ratio which is 1.7. Yes the specs on the cam you bought are smaller but that's not always a bad thing (depends on where you want the cam to perform). Also i'm going to guess the specs on the marine cam as far as duration is concerned is "advertised" and not at .050". You really need to be looking at lobe seperation angle to see if it is FI friendly (112-114* is ideal) if you start getting less seperation then that reduces vacuum which is what freaks the ECM out and causes trouble.
