razorguy

iTrader: (2)

I'm not making any final decisions yet, but I am most likely going to get an LT4 Hotcam kit and install it over the winter. My bolt-ons are beginning to feel slow, so I need a little more kick. I'm just shooting for a quick DD, and it beats enough cars already, but there are some that can get a nose on me..

Anyway, how much will this cause my gas mileage to go down? I have a '93 M6 and will keep the stock 3.23's in the rear so it does pretty good with just bolt-ons (about 26mpg or so cruising at 75 on the highway untuned). I expect to lose a little mpg, but if it's going to be drastic, I may decide against it..

And with the kit, I believe I read before that all it doesn't come with that are recommended to get are new lifters? If so, what are some good ones for this application?

Thanks, and sorry for another Hotcam question

SnakeOiler

iTrader: (6)

the hotcam is a dowel pin drive. Do you ( or have you) plan on switching your opti to a 95+ style?

Badazz 97 TA

iTrader: (18)

he can still use the cam without converting. im pretty sure you just have to shorten the dowel pin which is no big deal. (for a '93, '94 f-body.)


as far as gas mileage i didnt notice a huge drop at all. i maybe lost 1-2mpg's taking it easy. both highway and city

Pro_built7

iTrader: (9)

yes, all you have to do is shorten the dowel pin, no opti change is necessary, ( check www.shbox.com for exact shortening reference) with the mods in my sig, basically the same setup you probably have, I get about 17 city and about 24 hwy mpg with the hotcam, I honestly didn't notice too much of a mileage difference when I put it in (stock I was getting 18/26. It has a really nice sound too it too, and makes very noticeably gains.

Pro_built7

iTrader: (9)

http://shbox.com/ci/cam_install.html

there's the dowel pin lengths

bobdec

If you going to keep it a DD why replace the lifters unless you have high mileage or have noticed any sticking or collapsed lifter symptoms. The LT4 kit is not radical and for street driving the stock lifters should hold up to the requirements. That's my opinion, I left the stock lifters in to keep the geometry all stock GM to match the rest of the valve train. As far as mileage, it got worse so I never had the guts to measure it, I just fill it up with 93 and have fun driving. With my A4 the idle went from 550 D/650 P/N to 800/850 that burns more fuel and the kit will increases valve duration and increases lift to .525 that's means it's going to suck in more air and FUEL to get the extra 40 HP ?? when U hit the throttle.

firehawk238

iTrader: (1)

i drive a 95 firehawk with the LT4 hot cam in it. the cam was installed and tuned by MTI along with a barrage of other parts. everything from the cam up is performance tuned and matched. i went from 315hp stock to 440+hp and my mileage is 18 city and 24/24 highway. and on top of everything else, i run a 4.10 gear set in the rear end with an M6. car is brutal in 2nd gear. street tires are no match for the power, but my drag radials hold their own, as long as the rear end does.

karl

StealthFormula

iTrader: (35)

How many miles on the car? When you pull the lifters out check them to see if the rollers roll freely and they visually look in good shape. If so then just reuse them. Personally if I was near or above 100k I would spend $120 and buy some LS7's so you start out fresh and don't have to down the road do all the work to replace them.

You may lose a couple mpg but it will be well worth it trust me.

razorguy

iTrader: (2)

The motor has about 97,000 on it. I was thinking about pulling the motor and freshening up the seals and gaskets, etc when the cam went in anyway..

SnakeOiler

iTrader: (6)

If you are gonna go through that much trouble, then go ahead and replace the lifters. They are probably good, though, if the engine has been well maintained.

Some people don't think the LT4 springs in the kit are good enough, but there are many people who have not had any problems with them - myself included.

I still pull down 28 mpg on the highway - have no idea around town.

I don't what the other guys above are talking about, but pre '95 have spline drive opti's, not dowel pin drive. You will have to change over.

bobdec

Put the kit in my '94, all I had to do was shorten (grind down) the dowel to match the dowel length on my old cam. The dowel ends up flush with the CAM sprocket surface to provide clearance to the timing cover instead of extending out beyond it. In hind sight my original opti went out 6 months later. Since you have 93K on the car this could be a good time to spent the money ($500-600.00) on a type-II vented opti, new wire harness, new timing cover and vacuum hose setup required to convert. here's some pics of the differences http://www.noid.org/~muttvette/opti.html

SnakeOiler

iTrader: (6)

oh, my bad. the spline for the opti is actually on the cam gear - duh!!!