temperature problems

Berlin Germany

Registered
hi dears,

I got a ´01 busa with turbo with demaged head gasket.
motor data
cylinder big bore from dia 81 / 3.189" (orig.) to 83 mm / 3.268 "
complete MCX400 turbo kit
compression reduced from 10.5 to 8.8 : 1 (by thicker foot gasket)
turbo pressure max = 1.2 bar / 17.4 psi
test bench showed about 380-400 hp (at 378 km/h ~ 238 mph the test bench "said" stop ::-) )
orig. ´99 radiator + his fan

the situation now is :

gasket is changed and I made a - naked - test run (without both side panels)
result:
the bike´s pointer stays at bit under the middle of the diplay even after 20 minutes running (in/at idle) in my garage.

then i let the busa cool down to room temp. , mounted both side platics and let it run again with the result that the pointer now went up beyond the middle line
and i stopped the busa that moment.

then I dismantled both side panels again and a day later the owner made a test ride for more than 100 miles (& over 190 mph)

result:
not even a minor prob. - nothing - the pointer even stayed a bit under the middle line (temp. outside ~41°F) what ever he did - slow driving ~25-30 mph inside town / highspeed > 180 mph on the highway

damn - what now?

my idea - the, one, original fan on the left side seems not to be sufficient - so a 2nd fan should come, becaus the busa´s temperature runs perfect when busa is "naked".
but this brings me to another question - which one with which dimensions in terms of height / thickness and diameter?
so do YOU have any (other) ideas and/or poctured solution 4 me?


heeeeeeeeeeeeeeelp !

thanks :-)
 
Last edited:
The body panels being off are likely to be a coincidence. Search for the video that @c10 made showing how to burp the cooling system correctly.
 
  • Like
Reactions: c10
hi mr brown :-)
thanks for the hint.
i found the video where he (c10) burps a gen II busa
and that´s definitely the way it is described on my homepage
and it is my way to burp all busa(s) at my garage

so I think there is a coincidence / connection between naked or not.

please remember the turbo intercooler is mounted in front of the water rad.
and that way the fan possibly may be too weak to overcome the air resistance of intercooler, water cooler and the side panels vent openings sufficiently.
 
please remember the turbo intercooler is mounted in front of the water rad.
and that way the fan possibly may be too weak to overcome the air resistance of intercooler, water cooler and the side panels vent openings sufficiently.
That makes sense to me, the fan might not enough pull...

We have a very renowned turbo Busa builder on this site @Boosted Cycle Perf I'm sure he will filter his way along to give sound advice...
 
Yes, that's what I was suggesting. If the intercooler is blocking the radiator, a second fan isn't going to be helpful, it's not going to overcome the blocked radiator either. Move the intercooler....
 
Those mx express intercoolers make them run warm for sure. A second fan is always a good idea.

what stands out to me is before the head gasket problem it wouldn’t run hot with the fairings on. Only afterwards. Did you resurface the head and block before going back together? If not you may not have complete sealing of the head gasket around one of the water passages allowing for a slight loss of cooling system pressure. The less pressure in the cooling system the hotter they’ll run as the coolant will boil sooner with less pressure.

also if you haven’t yet, you should gut the thermostat.
 
Those mx express intercoolers make them run warm for sure. A second fan is always a good idea.

what stands out to me is before the head gasket problem it wouldn’t run hot with the fairings on. Only afterwards. Did you resurface the head and block before going back together? If not you may not have complete sealing of the head gasket around one of the water passages allowing for a slight loss of cooling system pressure. The less pressure in the cooling system the hotter they’ll run as the coolant will boil sooner with less pressure.

also if you haven’t yet, you should gut the thermostat.
Rob, if the head to block seal is not 100%, wouldn’t the combustion gas pressure be forced into the cooling system and not vice versa? The cooling system pressure is only 14 psi vs a hellova lot more from the combustion chamber.... am I missing something here?
 
1607634[/ATTACH]
(link 2 pic : http://www.fj1200-3cv.de/_Hayabusa/02-Motor/Kopfdichtung/Dichtung/dichtung.jpg)

but at this area there is no water duct or else so this can´t be the problem i think.
but now it is corrected

D - yes, shure, the thermostat hinders / limits the full water flow and you´re the 2nd with this hint ;-)
query - shall i cut away the 3 metall-legs so far that only the outer metal-ring & its rubber-ring leaves as gasket, (I think so, yes)
or do you have a special dealer for only this "gasket" ?
(f... ! - 4 that i have to dismantle all like throttle housing & plenum & ... again :banghead: )
 

Attachments

  • dichtung.jpg
    dichtung.jpg
    44.5 KB · Views: 67
Last edited:
Help me understand this Rob, if the I/c is blocking the radiator, how will a second fan help?
Jeremy, I can not answer for Rob, but here is my take on this question you have posed . .

1) the intercooler has airflow passing through it's fins/tubes which also passes through the radiator fins/tubes, the rad being right behind the I/C.

2) The air passing through the I/C is heated as it passes through and in effect adds a little more heat to the radiator than it would have, had it not passed through the I/C first. (if the I/C was not there at all)

3) So, a second fan will aid and multiply the cooling effect by drawing twice the airflow through the rad fins/tubes . . . but remember, this is only helping cooling when stationary or moving slowly, i.e city traffic etc. Having fans running while at highway speeds have little benefit at all. The airflow speed and velocity is greater than the fans can create.

So that's my logic on it, what do you think?
 
Those mx express intercoolers make them run warm for sure. A second fan is always a good idea.
(...)

Query / Demand - Is there another type of turbo air cooler,
fitting to the busa,
with the same size and cooling capacity, but less air resistance than the MX?
I know (by my job) that every pascal (intl. sign = Pa & 1 Pa = 0,00014504 psi) air resistance less can help a lot .
 
Last edited:
Help me understand this Rob, if the I/c is blocking the radiator, how will a second fan help?
Yeah going down the road that’s not gonna help. I did an old a2a mcx kit a few years ago. Anything less then 20mph it start running really hot. If you hit traffic good chance the temp light would come on.

kiwi, most cases that’s right. Ever done a wet compression test? Compression can push the gasket back in place and seal it, but the piston draws a vacuum on its way dawn. Just depends on the defect. I’ve seen a couple bikes over the years come in with complaints of always having to top off coolant periodically, running a little warm going down the road, but would stay cool at idle, never leak, smoke or overheat at idle. The fix was always machining the Mating surfaces and a new head gasket. Another one had a hairline crack in one of the cylinders.
 
Query / Demand - Is there another type of turbo air cooler,
fitting to the busa,
with the same size and cooling capacity, but less air resistance than the MX?
I know (by my job) that every pascal (intl. sign = Pa & 1 Pa = 0,00014504 psi) air resistance less can help a lot .
You did say the bike never had this problem before until the head gasket issue correct?
yes - and that happened twice with that busa

So you’ve blown two head gaskets already? What octane fuel do you run in it? 83mm bore isn’t the best idea on a turbo busa, but I’ve done a few that have made over 500hp without head gasket issues.

reason why I bring this up is the because I’m about 90% positive the limit on those air to air intercoolers was 14psi on 93 octane. So being at 17+ id suspect a decent amount of heat soak on a top speed run.

Where I’m going with this is your tune is likely the reason this has happened so many times. Being a touch lean, and/or hot intake temps at peak torque is a recipe for pushing head gaskets on an 83mm bore. Peak torque is when cylinder pressures are at their highest. If you don’t counter that in the tune that’s when the reduced size of the gasket between the cylinders starts to move around.
 
Jeremy, I can not answer for Rob, but here is my take on this question you have posed . .

1) the intercooler has airflow passing through it's fins/tubes which also passes through the radiator fins/tubes, the rad being right behind the I/C.

2) The air passing through the I/C is heated as it passes through and in effect adds a little more heat to the radiator than it would have, had it not passed through the I/C first. (if the I/C was not there at all)

3) So, a second fan will aid and multiply the cooling effect by drawing twice the airflow through the rad fins/tubes . . . but remember, this is only helping cooling when stationary or moving slowly, i.e city traffic etc. Having fans running while at highway speeds have little benefit at all. The airflow speed and velocity is greater than the fans can create.

So that's my logic on it, what do you think?
Your logic makes sense to a point, however if the i/c is not allowing air that is cool enough to get through the radiator, having more air isn't going to solve the issue. You're just going to move more hot air. Adding a second fan solves a low air volume issue, that's not what the OP has a problem with. A second fan helps with low speed and stationary temperature problems, this bike overheats going down the road. Does my reasoning make sense?
 
@ boosted...

no, sorry you understood it the wrong way.

the motor and turbo was built up brand new ~ 1000 mi (2 years) ago
bored from 81 to 83mm and new coated with nikasil (the seller said so and the color of cyl. tell me that) + new pistons

the head in & outtake canals/ducts are, as far as i know, a little bit cleaned - pouring uncleanliness - but not enlarged

the gasket change, i made now, was, as far as i know, the 1st time - remember new built motor

in germany you only get 92 octane or higher never lower and the owner fills in allways 95 octane
 
What method is used to determine octane? 91 ron (which I think is what you use) is the same as US 87. Your 95 is like our 91.
Is 91 enough for 17+ psi?
 
@ mr. brown

this motor overheats in idle running - on my lift - when sidepanels are mounted

and does not when its is naked

so i hope adding a 2nd fan will solve the problem

so i´ll go that way

if the 2nd fan + sidepanels on will not be sufficiant i´ll gut then the thermostat

I'll keep you up to date

give me some days - tomorrow i get a 4-day vistit of my dearly beloved brother & his girlfriend
and i won´t join my workshop ;-)


PS:
the upper limit is definitely 17.4 psi - no + possible
and please remember - temp. probs NOW are at idle
 
Last edited:
Back
Top