LB9GTA

iTrader: (1)

Is anyone running a flat solid cam with a stock tpi efi computer?

I am running the computer compatible xfi280 flat tappet cam presently and looking for a bit more power.

Night rider327

iTrader: (13)

I have no experience with a mech. flat tappet cam in an EFI car, but I would think the knock sensor would pickup the cam's lash chatter and think it's detonation/ping and retard timing.

cuisinartvette

Think those sensors are tuned to pick up a specific frequency so it wouldnt pick up everything. Lash who knows. There are sensors that are a little dumbed down so to speak maybe someone how has done this can pipe in

Big fan of the way solids run.

LB9GTA

iTrader: (1)

Bump, anyone running a solid flat cam in an efi?

I don't want to go carb!

LB9GTA

iTrader: (1)

Bump!

Anyone running a solid flat or roller cam with EFI?
TPI computer or otherwise?

FRMULA88

You answered your own question. The cam profile needs to be "computer compatible". You have to use a solid lifter cam with a profile that will not exceed the limitations of the stock ECM (emissions)

The knock sensor is tuned for specific frequency where knock occurs which is not same frequency as valvetrain noise.

I do not know of ANY solid lifter cam that will work in a OEM setup, pass smog and not make the "service engine soon light" stay on .

Aftermarket EFI is another matter since there is no OBD / ODBII smog test.

These cars are old enough that you can get a smog waiver if it's not a daily driver. Otherwise you are stuck using CARB certified parts to pass the smog testing in your area.

LB9GTA

iTrader: (1)

I'm not too concerned about passing smog tests, we dont have them here.

But I can't find any solid cam(roller or flat) that is computer compatible.

So I'm asking if anyone has tried running one with a stock EFI computer?
Or is it just too hard to tune? and not worth the effort.

FRMULA88

it wont' work (well) because the cam profile exceeds the parameters of the ECM.. you may not care about smog... the ECM does.. LOL

if you can reprogram the stock ECM have at it.. or go with an aftermarket system. There are plenty of race cars with solid roller cams and EFI..

Tibo

iTrader: (15)

Try sending tuned performance or rbob a private message asking this. Stock and modified ecm is there bread and butter, they have made and helped countless people.

articwhiteZ

iTrader: (56)

just takes a tune to have the knock sensor retared 0
and to the profile of the cam..its what Lingenfelter did to my car..

my camaro has always run a mech roller.. and the new eng is also a mech roller..just a tad under 620 lift and ballpark of 250@50..but its also almost 430cid. it's easy..

ramicio

iTrader: (-1)

I don't know how advanced these knock-detection systems are, but most of them detect certain frequencies and only at certain times. It knows when to expect knock. Just saying, if knock sensors are picking up mechanical noise, you have an old or crappy EFI computer. Hell, even with OBDII it became standard to sense how fast the crank should move after firing a cylinder, and they even factor in load, and if it's too slow you get a misfire code.

FRMULA88

Detonation aka Knocking has a very specific sound frequency which has been proved in the OEM's dyno rooms and proving grounds for decades.
Engine "noise" (valvetrain, rockers, etc all emit different frequencies)

The early knock sensors were tuned for this "detonation frequency" so when it was "heard" by the sensor the ECM pulled timing until the "noise" was gone, simple & effective.

The problem lies with aggressive cam profiles that throw off the ECMs smog control, timing, & fuel parameters so much that the stock ECM cannot "self tune".

You have to modify the stock ECM or go aftermarket.