PFF - Pennock's Fiero Forum, PDA Edition

LS4 / F40 swap - fieroguru (Page 35/216)

dobey

OCT 15, 04:05 PM

quote

Originally posted by dratts:
I might be showing my ignorance here, but I would think that the ls4 pump would be fine without the dod hardware. It's an upgrade over the stock oil pump right? I don't get the advantage of the ls2 vette oil pan/pickup over the ls4. Especially since the ls2 is for a longitudinal mounted engine and the ls4 pan was specifically designed for the forces that a transverse engine will encounter. I'm very willing to be enlightened.

As fieroguru mentioned, high volume pump could suck the pan dry, without the DoD hardware. Looking through other forums for various bits of LS-related knowledge, I came across a few posts where people who removed the AFM hardware on the top end to get to the higher RPMs, ended up with oil starvation issues, on the G8/Holdens. So, better safe than sorry, and the oil pump is a cheap/easy change if you're changing cams already anyway.

Also, as fieroguru posted, the Vette LS2 pan has much better baffling inside it than the LS4 pan (which actually has none). Also, the Vette LS2 pan is specifically interesting as it is a low profile pan, as the engine in the 05+ Vettes is mounted lower, so it makes more clearance for getting exhaust by on the front side of the motor if running a full exhaust system.

dratts

OCT 15, 08:57 PM

Thanks guys, I was thinking like fuel pumps that lots is good. I think that I had read a description of an ls4 with an oil pan baffled with the transverse forces in mind. Can't beat pictures though, I believe you guys, and as stated I managed to display my ignorance.

Kemp3

OCT 15, 09:35 PM

I am going to challenge this oil pump theory. I am sorry but it makes no sense as the engine has a bypass and once oil pressure is reached the rest of the oil is bypassed back into the pan. Unless there is something really wrong with a motor I dont see how it could possible pull all the oil out of your pan and put it some where else .

Dont believe me talk to a few engines builders .

dobey

OCT 15, 10:11 PM

quote

Originally posted by Kemp3:
I am going to challenge this oil pump theory. I am sorry but it makes no sense as the engine has a bypass and once oil pressure is reached the rest of the oil is bypassed back into the pan. Unless there is something really wrong with a motor I dont see how it could possible pull all the oil out of your pan and put it some where else .

Dont believe me talk to a few engines builders .

Oil Pressure and Oil Volume are not the same thing. If it wasn't an issue, then GM would use the same oil pump on the AFM motors, as the non-AFM motors to save the money, but they don't. The pump on the AFM engines displaces 1.26 in³/revolution, while the standard LSx pump displaces 0.95 in³/revolution of oil. That's a pretty big difference. The AFM pump may work fine for you, and if it does, hooray. It's a cheap thing to change (all you have to really change, is the spring in the pump), when you're pulling all the AFM hardware off. The AFM oil pans also have an additional relief valve in the pan itself, which could cause oil to dump back to the sump, when needed up top, on a non-AFM motor.

GM puts all this stuff on the AFM cars for a reason, and they don't put it on the non-AFM cars for a reason. Better to build the engine to the appropriate manufacturer design specs, than to risk potential problems, especailly when the changes are so easy to make. GM spent millions to research, design, and build the AFM/DoD system on these cars, so there's no need to ask an engine builder. We aren't building classic small/big block race engines here, where slightly different rules would hold true.

fieroguru

OCT 15, 10:55 PM

The LS4/F40 swap will now get an additional upgrade... switching from 12" to 13" brake rotors with a new brake rotor kit/design.

I have found a 13" rotor that based on the rotor specs should retain the 88 calipers and has a mounting depth that is slightly shallower than the current C4 12" rotors to avoid the lower A-arm rubbing, but not as shallow as the Viper 13" rotor that needs 8 caliper brackets. My setup will only need 4 caliper brackets (similar to the fieroaddiction 12" brackets), 4 concentric rings and 4 13" rotors that can be purchased for under $50 each... The rotors are also very close to the Viper rotor weight.

motoracer838

OCT 16, 10:07 PM

quote

Originally posted by fieroguru:

The LS4/F40 swap will now get an additional upgrade... switching from 12" to 13" brake rotors with a new brake rotor kit/design.

I have found a 13" rotor that based on the rotor specs should retain the 88 calipers and has a mounting depth that is slightly shallower than the current C4 12" rotors to avoid the lower A-arm rubbing, but not as shallow as the Viper 13" rotor that needs 8 caliper brackets. My setup will only need 4 caliper brackets (similar to the fieroaddiction 12" brackets), 4 concentric rings and 4 13" rotors that can be purchased for under $50 each... The rotors are also very close to the Viper rotor weight.

Can't wait to see more.

Joe

Alex4mula

OCT 18, 06:03 PM

quote

I will be looking for this too. Would be a great contribution

qwikgta

OCT 18, 09:57 PM

quote

More info, More info, More info.......... please.

Rob

kennn

OCT 19, 08:54 PM

WRX rotors?

Ken

------------------
'88 Formula V6
'88 GT TPI V8

fieroguru

OCT 19, 09:33 PM

quote

Originally posted by kennn:

WRX rotors?

Ken

Nope.