|
| | | Forum Guru
 
Group: Administrators
Last Login: 7/3/2009 8:49 AM
Posts: 59, Visits: 188 |
| | |
| | | Junior Member
Group: Forum Members
Last Login: 7/28/2009 10:35 PM
Posts: 22, Visits: 47 |
| Mike, has the new lite rod been a success?
What are the hrs before replacement now v's before with the old rod?
Cheers
4strokers go harder & last longer
Aussie-yamf200 |
| |
| | | Supreme Being
Group: Administrators
Last Login: 10/20/2009 5:34 PM
Posts: 198, Visits: 315 |
| | Kev As explained in the announcement the new lighter rod is strong enough to not flex but light engough to reduce some of the loads on the crank and rod bolts at high rpm's. Another benefit is that it brings the engine back into its correct balance range which in turn reduces vibrations that some encountered with the heavier rod. Contrary to popular belief the lighter doesn't offer a performance benefit such as "quicker" acceleration or higher revving, just smoother power and better reliability. Mike |
| |
| | | Junior Member
Group: Forum Members
Last Login: 7/28/2009 10:35 PM
Posts: 22, Visits: 47 |
| | Thanks Mike, when I do the rebuild I'll upgrade to the new rod. Rebuild will be some time off yet as it seems to be going really well. What is the recommended rpm range for this motor as I am hearing all sorts of figures. Obviously the higher the revs the shorter the service time, ie rod/piston replacement etc. I am pulling 8200-8300 consistantly, have run much higher 8900, but that getting up there hey!! I actually geared my kart down to 8200-8300 and still have shit loads of fun rounding up and doing quicker times than J's & S's over here. What a blast. Cheers Kevin
4strokers go harder & last longer
Aussie-yamf200 |
| |
| | | Supreme Being
Group: Administrators
Last Login: 10/20/2009 5:34 PM
Posts: 198, Visits: 315 |
| | Kevin The max rpm question is a little tricky so in order to put things in perspective I'll offer this scenario with a peak rpm reading of 8,800 each lap. One an asphalt sprint track you might reach 8,800 rpm briefly each lap (or every minute or so) and the rest of the time the rpm's are considerably lower and in the power band so the cycles/loads on the rod are not that great. On the other hand if you are on an enduro (long) track where the engine is full throttle almost the entire lap or an oval where the engine turns 8,800 twice a lap (or every 6 to 8 seconds) the cycling is significantly higher so the rod life would be proportionally less. The bottom line is rod life is tied to rpm's, along with rod and piston weight, so the more you run at high rev's the sooner they need changing. Mike ps- that is one of the reasons why we wrote rules for the F200 that limited breathing!  |
| |
| | | Junior Member
Group: Forum Members
Last Login: 7/28/2009 10:35 PM
Posts: 22, Visits: 47 |
| Thanks Mike, that certainly puts things into perspective. At this rate (8200-8300) being achieved spasmodically the rod should last some time. Gee it's good to get some action on the forum here, there for a while I thought your members had all hibernated but alas they do come out from the woodwork on the odd occasion. It's good to toss around different topics and to collect peoples thoughts and ideas. Everyone is different and as long as we can all agree to disagree on the odd occasion, the better we should be.
Kevin
4strokers go harder & last longer
Aussie-yamf200 |
| |
| | | Forum Member
Group: Forum Members
Last Login: 2/3/2010 1:14 PM
Posts: 43, Visits: 41 |
| | We are running on a sprint track, most are gearing to turn 8400-8600 at the end of our 900' straight, I replace the rod when doing a rebuild most will freshen up at the end of our 15 race season but for cheap insurance if I have a engine apart with 7 plus races I will install a new rod. Just found out one of the shops at the track has a flow bench, I have done 4 different types of port job on the 13 F200 R1 so curious to see the flow numbers. What has been interesting is that all make power a little different but lap time the same???? All part of the fun.
Miller Motorsports Park
Tooele, UT
www.millermotorsportspark.com |
| |
| | | Junior Member
Group: Forum Members
Last Login: 7/28/2009 10:35 PM
Posts: 22, Visits: 47 |
| That will be interesting to see Mitch. Obviously the Burris boys have come across a nice little porting profile with there head package. Just bought engine recently for a mate and as mate doooo..... I snuck a little peek at the port job.....very nice and yes it performs well. Nice work in the shop
Cheers
Kevin
4strokers go harder & last longer
Aussie-yamf200 |
| |
| | | Forum Member
Group: Forum Members
Last Login: 2/3/2010 1:14 PM
Posts: 43, Visits: 41 |
| | What we have found is that a sound/basic port work with a good valve job provides great power through out the RPM range 5000-8000. I keep looking for the magic head but when it comes to how they race all the time and effort might show some gain at a point on the track but the baseline head just pulls hard everywhere. I laugh at myself because I just have to keep playing around. I think with a open set up with more cam, compression and carb that Burris has been playing with would really work well with a couple of heads I have done. We will have a RWYB class on our oval program and I think I might have to built a Open F200 R1.
Miller Motorsports Park
Tooele, UT
www.millermotorsportspark.com |
| |
|
|