Thread: Stihl 084 and 088

I am wondering what is the differance in the two models? The specs. are the same on both.
Model Displacement (cm³) Power(kW/HP) Weight (kg)


STIHL 084 121.6 6.3/8.6 9.4
STIHL 088 121.6 6.4/8.6 9.9

Was it changed to meet emissions/EPA Regulations? Or is there major internal differences in the two powerheads?

Hello George,
The 088 and the 084 are the same sized motors but there are considerable differences inside. the 088 develops more power than the 084 does when they do stock. the factory changed a number of the things we were doing on our woods modifications, all for the better. they changed the combustion chamber volume from 13.5 cc to 11.5 cc. they lowered the squish clearance from .043 to .034. both these mods increased compression. they changed the transfer duct so it is now a straight shot into the barrel. the tonsil that hung dowm into the 084's inlet duct is now gone. they increased the exhaust duration slightly and changed to a slightly larger cast aluminum muffler. Also went to the newer fiberglass flywheel. probably has 1-1.5 more foot pounds of torque. also the lower transfer area in the case is larger so you can process more air-fuel mixture. all in all the 088 is a better saw
i have 2 new 088's left to modify if anyone is interested. put in a photo of one of my 084's making a .9 second cut in a 8 by 8 cant
ken
kdhotsaw@hotmail.com
530-589-2744

Ken, what is the biggest bar that a stock 088 can effectively pull in the softwoods out your way??? i've seen pics of people running 72'' bars but was wondering

hello ryan,
up on the north coast in california in the redwoods they are currently using up to 8 ft bars with skip chain . lots of 4-5 foot bars used on that sized saws. we should check with uncle Art(Art Martin) , I think he used to use longer bars than that when he was falling up there
That is a 28 inch bar i'm using in the photo to test that size racing chain but normally use my 17 inch bar. can get the cutting time downto .6 seconds with that sized bar and chain with a pipe fitted to the 084 stihl. that particular saw now belongs to none other than the legendary gypo logger john lambert
ken

Ken,

Are you saying that the 084 is not a "good saw"? Or that in its original form was lacking power? Stock to Stock, how much more power does the 088 have over the 084?

GeorgeW

thanks Ken!! on that size bar are people running 3/8ths or .404??

Hello George,
The original stock 084's just didnt run all that great stock. when we modified them they ran very well. they were designed 10-15 years before the 088's came out. Stihl realized that they could make power by changing some of thier port timing figures and some of the bottlenecks in their 084 designed saw without losing any of their dependability so they incorporated many of the features we put in our modified saws. viola! more torque, more cutting power. the hp and torque figures are almost the same but the two saws don't run the same, the 088 has 10-15 more power stock and 35-40 % more power modified.
ken
kdhotsaw@hotmail.com
530-589-2744

Ken,

Can the performance gains be aquired by only cylinder modifications? Or are crank case mods also required?

GeorgeW

hey i was wandering where a guy could find a parts 084 or where to get cylinder for one for 150.00 or less

Start a new thread... you'll get more hits that way...

try ebay.

Gary

[QUOTE=kdhotsaw2;73450]

the tonsil that hung dowm into the 084's inlet duct is now gone.

does removing the little tonsil increase power?

Originally Posted by markvanzee

the tonsil that hung dowm into the 084's inlet duct is now gone.

does removing the little tonsil increase power?

I would not remove it.

Sometimes an 8 1/2 year old post is a gem, like this one.

Originally Posted by 2dogs

Sometimes an 8 1/2 year old post is a gem, like this one.

+1

Originally Posted by kdhotsaw2

the combustion chamber volume from 13.5 cc to 11.5 cc. they lowered the squish clearance from .043 to .034. both these mods increased compression. they changed the transfer duct so it is now a straight shot into the barrel. the tonsil that hung dowm into the 084's inlet duct is now gone. they increased the exhaust duration slightly

If true, that's good data.

The compression ratio on my 084 was indeed lame, in stock form.

084 transfer duct looks just like other Stihls to my eye.

084 exhaust duration about 170 degrees, dunno why it would need to be increased.

Originally Posted by mtngun

+1


If true, that's good data.

The compression ratio on my 084 was indeed lame, in stock form.

084 transfer duct looks just like other Stihls to my eye.

084 exhaust duration about 170 degrees, dunno why it would need to be increased.

The comp on my stock 084 is about 140 psi. What is the norm?