1989 IROC Z28 L98 350 ZZ4 Cam Speed Density Rough Choppy Lopey Idle

[SimplisticBeing]

Nice..

Speed density is tough for those who are used to MAF and like throwing mods on without care of tuning..whereas Speed Density is all about tuning..

My buddy had MAF all his life and bought a Foxbody with Speed Density..he was lost..but only because his knowledge was all about MAF and throwing parts on a car without ever thinking about tuning.. To Each His Own..

I like knowing both..just so happens I bought a car with Speed Density..

P.S. Me being a computer nerd..this sounds like fun..

[chevy385]

@SimplisticBeing Yeah, the MAF setup with this car worked great with the ZZ4 cam but the Speed Density(for me) was too tough to tune. I messed a lot with it on my 93 Suburban and I can change shift points and idle speeds and things like that but I don't have the patience to do all the fuel tables and stuff. I would love to be able to do it though. Oh well.

[APontiacof455cubes]

I thought they changed to speed density in '90 for the L98

[chevy385]

@APontiacof455cubes They did. The LB9 did also. I converted this one myself. But eventually changed it back to MAF

[APontiacof455cubes]

@chevy385 yea idk why the hell anyone would want speed density. Easier to tune, yes but inconsistent. And it seems ur kinda limited for making power with MAP vs MAF.

[chevy385]

@APontiacof455cubes Speed density is only inconsistent when it isn't tuned right. Stock for stock a MAF car will make just a bit more hp/tq than a SD car. You are wrong - the power limiter is the MAF sensor in a MAF setup. The computer is the problem since the MAF table does no go large enough to support large amounts of naturally aprirated horsepower. However you can fudge it with forced induction by using a boost referenced fuel pressure regulator. So the win goes to speed density.

[APontiacof455cubes]

@chevy385 ok. so tell me why they switched back to MAF in '94? Why dont all other high performance cars use speed density?

[chevy385]

@APontiacof455cubes A lot of newer vehicles are both. But the reason they switched back is because they had an ECM that didn't have the limitations of the stock '165 that was in the late 80s F-bodies. A lot of folks who modify newer stuff take the MAF out which pretty much speaks for itself

[chvelle69]

this car sounds sick but u should of hit the gas to make the video even more sick

[chevy385]

Thanks. You know what though in all of my videos of it I don't think I rev it in any of them. Hmmm. Oh well. Not mine anymore so I can't. Sorry

[chvelle69]

@chevy385 is this camaro stock?

[chevy385]

Everything except the cam and it has a Hypertech air foil. Oh and wasted K&N air filters. Exhaust is stock replacement, cat is hollow, all the emissions stuff is hooked up and working.

[chvelle69]

@chevy385 thts good for a 89 camaro iroc z28

[chevy385]

It is but the guy who had it before me did a hack job on a lot of stuff so I had to repair/replace a few things. The engine being one of them

[chvelle69]

@chevy385 of some owners juss puts mad stuff in their cars wen their not even relizing it

[ChrisXCXCX]

Hey, Can you cam these engines out were they lope?

[chevy385]

Of course. But you will need to do a lot of tuning for a cam with a decent lope. When I put the ZZ4 cam in my with the stock MAF setup it idled a little rough but there are much bigger cams out there.

[LaloGsxr]

@chevy385 hey man i gotta a question my formula has a ZZ4 cam in it but the guy who put it in cant remember the numbers for it cause i need to get it tune , so i was wonderin if u might have any clue is to what they might be BTW mines a 91 formula 350 5.7 TPI ?

[chevy385]

208/221 @ .050 .474/.510 lift w/ 1.5 rockers 112 LSA

[outcastMETALchild89]

nice...i have an 87 iroc with the 350 tpi(all stock) what would adding 1.6 or 1.7 roller rockers do? i know it would give it a higher lift but would this make it idle a little more choppy? thats what i'm trying to do w/out changing cams. thanks.

[chevy385]

the stock cam was not designed to idle rough so there is really no way to get a rough idle without changing the cam out. The ZZ4 cam I had in mine was great. It gave the car a good kick in the ass and idled just rough enough to let ya know it wasn't stock.

[jimmyman1991]

the rough idle is caused with cams that cause valve overlap...the more they over eachother the more choppy/rough your idle...higher lift will just put more to the chambers and more pressure out the back

[jesse8t]

i have a 1986 corvette l98 aluminum heads...all stock..i want a REAL lopey idle..any ideas guys??

[chevy385]

My ZZ4 cam idled choppier with the MAF setup then the Speed Density but if you want a real rough idle you are gonna have to do some serious tuning. You could go with the LT4 Hot Cam setup. But the idle is not terribly rough but you can tell it's not stock

[outcastMETALchild89]

ok, but will my computer handle it? if i really don't have to change much i'd put that cam in..

[chevy385]

mine ran fine without any tuning but to get the most out of it you should have it tuned. for the most part anything that is gonna give a rough idle you will most likely need some tuning

[outcastMETALchild89]

ok, thanks. could you explain what would happen if i put in 1.6 or 1.7 roller rockers?

[chevy385]

you would be adding a little bit of lift and duration at the valve. to the engine it would seem that your cam was a little bigger.

[outcastMETALchild89]

ok, so..how would that benefit? any power/torque increase? would the engine sound a bit different at idle? thanks.

[chevy385]

you will get a bit more hp/tq but the sound change would be too minimal to notice. 1.6 would be fine but 1.7s you may need to change your pushrods to correct the angle of the rocker on the valve

[krayziek420]

a little warning: PUT SCREW IN STUDS ON YOUR HEADS, YOU WILL PULL THE STOCK PRESSINS WITH THIS CAM! YOULL GET FIFTEEN HUNDRED MILES BEFORE IT HAPPENS IF YOUR LUCKY! B WARNED! sounds great for stock replacement sounds better than my junk magnaflow.

[chevy385]

I am not sure why a stock muffler sounded that good but it did, go figure. Sounds almost like a super turbo but it was only $20! I sold the car so I don't have to worry about it anymore but I will remember that next time I use that cam because I have another one yet.

[GRYNCHESP]

305?

[chevy385]

L98 350 bored +.030 so actually it is a 355

[chevy385]

thanks! runs nice and beefy ;-)

[cherrynutz]

I just bought a zz4 350 for my 73 vette I can't wait to hear it in person. Yours sounds great!

[chevy385]

Thanks!

[SIPDE1st]

just curious, what all did you need to change to put in the cam?

[chevy385]

absolutely nothing. I probably should have done the valve springs, but the ones that were on the engine, which I am not sure if they were stock or not, had no issues with coil bind or any valve floating problems so I left them on there. The ZZ4 cam has a lot more lift than that stock one which is why I was worried, but no such problems, so all is well.

[chevy385]

Oh yeah, and had to do some tuning also. Other than that it is still all stock.