Koso,Digatron or Racepak II?Anyone have a preference?

lloydguy

Active VIP Member
Joined
Nov 29, 2010
Messages
889
Reaction score
1,499
Location
Lloydminster
As per title I'm looking at purchasing one of the above.I have a 99 summitX and the engine has
unknown perf.mod's.DPM has been removed and the jetting was 4 sizes down from stock when I got it.
I am NO sled head,and wanted to maybe purchase EGT gauges while I'm trying to get the engine
dialed in.Any advise would be great.Thank's
 

shoppingcart111

Active VIP Member
Joined
Sep 21, 2007
Messages
1,685
Reaction score
559
Location
Edmonton
I've had the koso single and duels and they were great, but now I have a two window digi with twin egts and CHT and rpm, and love it now more, way more versatile. The alarms with the increasing leds is awesome.
 

lloydguy

Active VIP Member
Joined
Nov 29, 2010
Messages
889
Reaction score
1,499
Location
Lloydminster
What model of Digatron do you have now?Any reason you got rid of the Koso?
 

WopOnTour

Active member
Joined
Jul 9, 2011
Messages
107
Reaction score
87
Location
CA
If you're not a sled head, you dont want a Racepak.
It's easily the most comprehensive, (especially models with GPS and accelerometers)
Cool and all, however you'd probably be swamped over with data. (and much of it useless unless you're racing)

If you're determined to tune it yourself keep it simple and stick to something that can give you just accurate EGTs & RPM and maybe coolant temps like the Digitron.
Get a fresh set of plugs and a set of head gaskets so you can inspect your wash and expect to spend a day jetting
Do this on a day with a consistant temperature and at a known or measured altutude +/- 300 ft. (and record them!)
OR even better...
Save your money on expensive wizz bang data loggers, pyros and sensors
Instead, just take it to a dyno local service and have your jets set (suggest starting stock "fat") and to establish your peak HP/TQ RPMs so you can always clutch to them
i.e. primary weights/cams/spring to shift out at ~max horsepower rpm, and the backshift loaded up in the deep stuff via secondary spring to ~your peak torque rpm

Then use the $10 Mikuni pocket tuner to quickly calculate and adjust your jetting from there specific for the riding area based on temps and altitudes.
Ultimately this is just pure math once you have established your optimum baseline setup on the dyno.

With the pocket tuner I just use ride start + finish altitude divided by 2 but you can always rejet up high if you start to slobber (and take it a bit easier at the start of the ride OR if you drop into a major depression and get lower than your starting altitude)
ALWAYS KEEP your dyno sheets (I laminate a set and keep them in the trailer) so you always know your numbers and the temps and corrected altitude they were created at.

K.I.S.S. can really apply here as long as you have a well defined starting point.

HTH
WopOnTour
 
Last edited:

lloydguy

Active VIP Member
Joined
Nov 29, 2010
Messages
889
Reaction score
1,499
Location
Lloydminster
Thank's for the info.I have learned more about reading plugs than piston wash(so far).So once I fire it up
again this year,I have alot more tuning to do.I have bought a D.P.M module and plan on installing it back
onto the sled.Stock jetting if I recall was 350,340.Sled was 310,300 when I got it.
I'm pretty sure the way I had it last year was 360,350.I'm reading and trying to learn as much as I can,
so I can save cash on what I've got invested into this sled.I have a box of new plugs ,so once some snow
hit's the ground I am ready to start with my learning experience.Piston wash will be the next reading material
after I print off some of the stuf I have found on reading plugs.
I just thought for afew hundred bucks egt.gauges might help with tuning.
 

boots

Active VIP Member
Joined
Dec 20, 2008
Messages
1,726
Reaction score
318
Location
ardrossan
i am running a racepak III.... i dont mind it ....better then the racepak I.... it has a back light for night time and has a recording feature for doing some fine tuning
 

Modman

Active VIP Member
Joined
Mar 13, 2008
Messages
6,032
Reaction score
8,459
Location
Castlegar
As per title I'm looking at purchasing one of the above.I have a 99 summitX and the engine has
unknown perf.mod's.DPM has been removed and the jetting was 4 sizes down from stock when I got it.
I am NO sled head,and wanted to maybe purchase EGT gauges while I'm trying to get the engine
dialed in.Any advise would be great.Thank's
https://www.snowandmud.com/forum/14/exhaust-temps-40883-3.html look through my response on the top of pg 3 of this linked thread, it has some links in there that will help you establish your baseline. You can also search "plug reading" and "egt baseline jetting" on here and get some other good answers as well. I like the Koso's for EGT's, they are a great gauge, but if you get an A/F gauge just get an automotive style one and hook it to a rectifier. You can search that on this website as well.

Hope that helps.
 
Top Bottom