This engine will be of real interest to alot of MIRA enduro/sprint racers
as it is the engine most racers will be using.

I will do a step by step dyno tune starting from the stock specification


so lets get going.

engine state of tune.
-stock engine
-stock head
-stock pipe
-stock silencer
-stock 38TM carbs
-360 MJ
-open carbs
-sunoco 116 32/1 inline oil
-squish 0.062
-stock timming

I started out with my normal warmup routine of warming up the engine
to about 70 deg. coolant temp, then I put a load on the engine and 3
warmup passes to simulate three practice holeshots on the track, then
a full load pass from 7300 ish to 8000-8100

This is the baseline run IQ6-S1



Let me explain what is on the sheet...corrected torq, corrected HP,
fuel flow in LBS per hour, and fuel burned per HP in lbs per hour, Air temp
in the dyno cell, water temp as it is leaving the motor, the exh1 exh7 are
disconected and dont mean anthing here.


end

The next thing I did was to install an aftermarket silencer, I call Kutter
to ask if there was anything he wanted to do on this dyno study and
he said that he thought an after market silencer gained HP on another
dyno...so the only one I had to try was the SLP silencer that was
nichol platted(please excuse my poor spelling and grammer), this
what I ended with

IQ6-S2



Mike was right on...it gained a bit...If you note the fuel flow per
HP(BSFC) both are running about the same fuel burn.


end

The next step installing a Hot Seat aftermarket head with higher
compression, the stock compression is about 11.6/1 with 0.062
on the squish. The Hop Seat head is 14/1 with 0.055 squish, the fact
that we are closing up the squish will always pick up some power.

Adding commpression will always add power in the midrange and add
a little on peak most of the time. however, adding compression
does hurt the power after peak and lower the peak power RPM

IQ6-S3



this is what we ended with...FYI I had taken the SLP silencer back
off, this run is with the stock silencer.

end

The next thing I did was install 38TM carbs bored out to 41.5mm.
these carbs have been sitting around for awhile. I had trouble getting
this setup to idle properly...ended up spending 30 min cleaning
the carbs.

The engine didnt like these carbs, If you look at the BSFC we are in
the .56-.57 range which is way to lean....if it wasnt for running 116 oct
fuel to stave off detonation this would have been a sqeaker for sure.

I want to say somthing about the 116 oct sunoco...I like using the
higher octane for these type of situations, there is always more power
in running the lowest octane you can, after I have done all the swaping
around of parts I start my oil and fuel study to find maximum power.

Here is the run...look at the BSFC numbers, I ended up having to put
410 to get this.

IQ6-S4



remember that this is with the stock silencer...there was about two HP
in the SLP silencer...we will switch back to this in the end.

end

I quickly put 450 jets in this to richen things up some.

IQ6-S5



it a little better...at least I am more at ease with this jet spec....I would
race with this jet at the track with a c.r.a.d of 98.

The last thing I did today was to reinstall the SLP silencer...the last
time we got 2 HP with a little richer BSFC...and again we gained about
2 HP

IQ6-S6




Here is a chart with all the runs all together, IQ6-S1 and IQ6-S2 are
reversed on the chart.



I hope you have as much fun reading this as I did doing it...If you have
any questions I will try to answer them.
chow

end

PROTON

Why were you using SUNOCO 116 in a STOCK compression motor??
Opps I now see where you explained that in the second post, but did you ever change the fuel to compare it

What year engine,pipe,spec?? Was this the HO motor?

Running that fuel will cost HP loss in a stock compression engine, and give you faulty readings by adding items that increase compression and pipe heat like a silencer. That alone will make the HP difference you saw. When we ran our 08 IQR 600 on your dyno, we saw that immediately, that it did not like High octane fuel and it lost signifigant HP using it


prochamp

I always look forward to your comments, you ask good questions,

I used the 116 as a safety net when I changed a bunch of things that could prove
deadly on the dyno, I agree with you on the fact that HP will
suffer as a result of the 116.

I didnt know if the box had been tampered with, as it turns out it was
reprogramed, Rader and myself came up with a new timming curve to try
(Im am building a set of twins pipes to run at 8500), So I am waiting to
get the box back....so I was a little gun shy on trying higher
compression heads without the 116.

Once I finnish with all the switching, I will drop the octane and see
what HP I can get.

2006 IQ 600 HO with stock heads stock for the year pipes and what
I thought was a stock box with a goofy curve(according to Rader)

What really supprised me was how the 41.5mm carbs were poor performers.