quote:Originally posted by irongoose

quote:Originally posted by Frankenstein

Don't forget we are talking a few thousands that we have added to the combustion chamber. This may take the compression down by 1/100s or so (did not do the math), so instead of 10.25:1 it might now be 10.24:1. AT the same time the volume of the combustion chamber has been going up by that same amount. You can't tell the difference on the dyno, only that the mode will not ping even in HOT wheather and on crappy california gas.


I'm sorry, curiosity got the best of me on this one too. I've done too many motors not to dispute this. Doubling up the Head gasket would have to make a little more impact than that, so I did the math.

Compression ratio = (Cylinder Volume + Chamber Volume)/ Chamber Volume

CC Volume OF Gasket = .7853982 X BORE* X GASKET THICKNESS


Stock Motor Values:

835.05cc = Cylinder Volume (stock: based on manual)
103.60cc = Chamber Volume (stock W/0 GASKET: based on manual)
9.45cc = Extra chamber volume from Stock gaskets
.1278cm = Gasket's thickness (based on plugging in above #'s)
thats 0.050" thick (sounds about right)
113.55 = Total Chamber volume
8.36:1 = Compression Ratio (stock and verfied in maunal)


With 10.25:1 pistons
90.27 = Total Chamber volume w/ stock gaskets
94.99 = Total chamber volume w/ 2 head gaskets thick

9.79:1 = New True compression ratio USING 2 HEAD GASKETS


I can definitely see this stopping your pinging problem, but you definitely lossed some horsepower in the process.
Bottom line, pinging is no good and you still have more horsepower than stock, so if you have this problem, it's definitely a solution. Hopefully this helped clear up some of the debate.


Eric,....Thank you for confirming my concerns on the actual true numbers loss by doing your home work, which is critical to having true spec's to a modification as involved as this one. As Bill had mentioned, I would be concerned of the longevity of stacking 2 head gaskets on top of eachother, when in truth it only requires 1. This creates a soft spot for blowing out a head gaskets under heavy load as one might experience during drag racing or high mileage riding. I am not claiming to be the know it all, but the head gasket is the one most critical point of sealing the heads to the jugs. By adding an extra gasket would require more torque to get it to seat/seal properly, which in turn puts more stress on the aluminum heads, jugs etc. I am just glad I do not have the pinging issues some folks are experiencing, but then I run 93 octane when possible and have an excellent custom map, SS ECU right along with Orient Express 10:50.1 high compression pistons. Not that it helps some folks, but it helped me. Very interesting topic, regardless. Good write up Oliver & Eric!

 

I wonder if some of the pinging issues have to do with fuel quality in some areas. I know the legislations in the western states love to dick with your fuel chemistry. Would not the SS ECU help also, doesn't it have a slightly retarted spark curve when compared to stock?

Could we use 2 or 3 base gaskets to achive the same thing - thus increasing the volume @ TDC
that way you maintain the integrety of the head gasket and mating configuration.

 

Yes, they change the formula in November (I think). Does not affect the ping, but it sure kills my MPG.

I know a couple of riders who have the complete SS package (ECU, pistons, and cams) They don't complain about pinging. I think SS does have a different spark curve, maybe more valve overlap too.

Extra base gaskets are another way to go, but then you gotta drop the rings. Whole nother bag o worms. Anyway I don't see a problem with double head gaskets... not at 10:1 anyway. Single bore... No water jacket... No Sleeve... It'll hold.

I would like to see the theoretical chamber pressure. Alan posted up some formulae, makes my brain itch just thinking about it. Volunteers??

quote:Originally posted by Jon_Cocktoastel

I wonder if some of the pinging issues have to do with fuel quality in some areas. I know the legislations in the western states love to dick with your fuel chemistry. Would not the SS ECU help also, doesn't it have a slightly retarted spark curve when compared to stock?

Could we use 2 or 3 base gaskets to achive the same thing - thus increasing the volume @ TDC
that way you maintain the integrety of the head gasket and mating configuration.

 

Excellent topic, I was thinking about some of the same issues riding my bike to work this morning.
There are some subtle and many down right obvious characteristics inherent to bumping the compression & changing cams.
Anyone considering these mods needs to understand they do affect all-round streetability.

From my experience :

*You will have go to a higher octane fuel.

*Proper mapping becomes even more crucial.
Wetter is probably better (definitely safer in town) even if it means sacrificing some of the sought after power gains.

*You can no longer lug the engine like you could when it was stock. Keep the revs up and stay in the right gear.

*Install a heavy duty clutch spring and lube clutch cable.

*Avoid hauling more baggage than necessary especially when riding two up. Stay in the wind on hot summer days.

* A new battery is a good idea and change oil often.

My bike runs really good I like it, but one should not expect "too" much when performing these mods and know that they aren't without trade-offs.
Opinions may vary, these are just things I learned.

 

This topic is one for the books. Very good information that has been applied with success.

 

The speedstar ECU does have a different ignition curve. When commined with a good custom map file, should do the trick too.

I sit my bike in stop and go traffic all the time with no pinging, but then we have 93 octane on tap all over here. Though I can't see having any problems with anything over 90 Octane either.


quote:Originally posted by Bladerunr

I know a couple of riders who have the complete SS package (ECU, pistons, and cams) They don't complain about pinging. I think SS does have a different spark curve, maybe more valve overlap too.






Would not the SS ECU help also, doesn't it have a slightly retarted spark curve when compared to stock?

 

Guys the speedstar ECU does not solve the ping by itself. 357Warrior came to me AFTER installing the Stage IV ECU and experiencing lots of ping during hot days.

 

quote:Originally posted by irongoose
I'm sorry, curiosity got the best of me on this one too. I've done too many motors not to dispute this. Doubling up the Head gasket would have to make a little more impact than that, so I did the math.

Compression ratio = (Cylinder Volume + Chamber Volume)/ Chamber Volume

CC Volume OF Gasket = .7853982 X BORE* X GASKET THICKNESS


Stock Motor Values:

835.05cc = Cylinder Volume (stock: based on manual)
103.60cc = Chamber Volume (stock W/0 GASKET: based on manual)
9.45cc = Extra chamber volume from Stock gaskets
.1278cm = Gasket's thickness (based on plugging in above #'s)
thats 0.050" thick (sounds about right)
113.55 = Total Chamber volume
8.36:1 = Compression Ratio (stock and verfied in maunal)


With 10.25:1 pistons
90.27 = Total Chamber volume w/ stock gaskets
94.99 = Total chamber volume w/ 2 head gaskets thick

9.79:1 = New True compression ratio USING 2 HEAD GASKETS


I can definitely see this stopping your pinging problem, but you definitely lossed some horsepower in the process.
Bottom line, pinging is no good and you still have more horsepower than stock, so if you have this problem, it's definitely a solution. Hopefully this helped clear up some of the debate.


Get it my guess was off. But here is a little curveball for you:

I just measured an actually used head gasket(has been compressed) and I got a thickness of 0.57mm or 22 thousands. Thats only 4.21cc for the stock engine and less than 2cc for HC pistons.
In addition the shop manual specifies the head volume as a range from as low as 98.6cc to as high as 103.6cc.
Now the Yamaha Stage IV HC pistons are 10.2:1 (per stage IV manual) vs PR and OE HC pistons of 10.25:1.

That would mean that the double head gasket mod drops the compression ratio to about 10:1 a reduction of 2 points of compression ratio.

Lets say HC pistons gain 5 hps, this delta will cost you roughly 0.5 hps - can't measure that with a dyno.

Now some people have suggest to retard the timing. A 2 degree retard will cost more than that.

If you don't have the problem. Ignore this mod.

If you have this problem (like almost all guys in CA who went to HC pistons) this will permanently take care of it.
Last but not least an engine that pings makes a LOT less power AND destroys itself over time.

 

quote:Originally posted by Frankenstein

If you have this problem (like almost all guys in CA who went to HC pistons) this will permanently take care of it.
Last but not least an engine that pings makes a LOT less power AND destroys itself over time.


In the end, this is really all that matters. Oliver, thanks for the awesome write up and detailed info on it.[/emoticons/emotion-2.gif]

 

****, now I really don't know about those HC pistons I was gonna pput in! I soo confused.

 

Naw, dont let that scare you I was thinking of Yamabonding my cilnders on instead of using a base gasket to pump it up a couple of decimal points. [/emoticons/emotion-2.gif]

 

Ok I've been reading this thread since the beginning. this double headgasket thing may work now but I don't think it is a permanent fix. I have been a mechanic and wrenching for at least 9-10 years. I can't tell you how many turbo cars I have seen double up headgaskets to reduce there compression for more boost. sure it works for a month or two but they will fail when you do this. I have NEVER seen somebody run 2 headgaskets and have them last any length of time. Running two base gaskets definately sounds like a much better approach to me.

 

quote:Originally posted by ehacker01

Ok I've been reading this thread since the beginning. this double headgasket thing may work now but I don't think it is a permanent fix. I have been a mechanic and wrenching for at least 9-10 years. I can't tell you how many turbo cars I have seen double up headgaskets to reduce there compression for more boost. sure it works for a month or two but they will fail when you do this. I have NEVER seen somebody run 2 headgaskets and have them last any length of time. Running two base gaskets definately sounds like a much better approach to me.


Agreed

Kyle

 

Just to be clear the number of gaskets is totally artificial to use in a debate whether it works or not. The OEM gasket is already 3 gaskets layered ontop of each other. According to most arguments used here that would never hold up.
I have 15k miles on the turbo with the very same mod and up to 25psi of boost. This mod is very specific to this engine and you should not compare differnt gasket materials, different engine technologies and throw them all into one pot. The Warrior has a wide head gasket and the extra two pounds of torque have prooven to work long term on the turbo.
I try to not put too much weight on theory alone. You need to R & D. I especially find projects challenging that everybody else says can't be done.

Remeber when I first started talking about putting a turbo on a Warrior. How many people told me it can't be done, would not last, is impossible?

Anyway - if you have the problem and can't get it fixed this will work for you just fine. If you are about to install HC pistons it might be worth doing it as well. And yes the base gasket mod will work just fine too.

 

Great stuff, thanks everyone. Mine, with OE 108, 10.25 pistons, OE cams, pings like crazy on 90+f days with 91 octane but runs very well using Outlaw Octane booster.

 

Great write-up. I will definitely do this if I go with the SS Stage IV. Thanks again for the write-up Oliver!

 

quote:Originally posted by Frankenstein
I just measured an actually used head gasket(has been compressed) and I got a thickness of 0.57mm or 22 thousands. Thats only 4.21cc for the stock engine and less than 2cc for HC pistons.
In addition the shop manual specifies the head volume as a range from as low as 98.6cc to as high as 103.6cc.
Now the Yamaha Stage IV HC pistons are 10.2:1 (per stage IV manual) vs PR and OE HC pistons of 10.25:1.

That would mean that the double head gasket mod drops the compression ratio to about 10:1 a reduction of 2 points of compression ratio.



Thanks for the exact crushed gasket measurement. Using that, taking into account the full range of the head volume, with PR'S Pistons, your new compression ratio is between (10.02:1 - 9.98:1). So you are correct in saying 10:1 is roughly your new compression ratio. Sorry for getting overly technical, but with motor internals, I need to know exact #'s

 

WOW! First time I see this thread.......first of all I wanna thank Oliver for doing this mod for me.

I had been having trouble with pinging and had tried many other alternatives like S* ECU, fuel booster and even 100 octane fuel with no success, I also had a custom map done.....still was pinging.

After Oliver installed double gaskets I have had no pinging and it has never run better and felt more powerful. Now I can get on the throttle in any gear and feel this baby respond[/emoticons/emotion-5.gif]

I rode it back home from Oliver's house 350 miles away and averaged 80-90 MPH all the way home with no problems.....I even kick the crap out of a HD that was looking to race, but love to report that the guy never knew what hit 'em[^][/emoticons/emotion-12.gif]

 

Great it's working for you.
IMO - if you tried 100 octane and that didn't work. You had something else going on..

But hey , its great your happy

Kyle

 

quote:Originally posted by MacWarrior

Great it's working for you.
IMO - if you tried 100 octane and that didn't work. You had something else going on..

But hey , its great your happy

Kyle



Same here, glad to see it solved your problem.

 

I've said this before but it was quite a while ago. When installing PR 10.25 pistons I had the combustion chambers, valves, piston tops and exhaust ports thermal barrier coated. I run California 87 octane with zero pinging. I'm a bit surprised the turbo guys, including you Oliver, haven't gone this route. Tests have shown there is virtually no hp increase to a water-cooled V8 motor but I feel an air-cooled motor like the Warrior's benefits from running cooler.

Performance Coatings did my motor for around $200. I have peace of mind and save a little with each fill-up and if anything, have increased performance to boot. Just my $0.02 worth.

The older I get,
The faster I was.

When I was fast,
Motorcycles were slow,
Now motorcycles are fast,
And I'm slow.

 

I think I just experienced pinging for the first time yesterday.
I heard loud ping-pop that sounded like aluminum baseball bat hitting a ball or a metal golf club hitting a ball from the pipes after being in stop-n-go traffic on a hot day.
The noise occurred under acceleration & also felt a power loss/mis-fire.
the pipes also rattled alot. Does this sound like what you are experiencing?
This also started 20 miles after filling up fuel tank at a pump that did NOT have a designated
hose for premium fuel. I'm hoping that I just got a bad tank of fuel.

My bike has the full PR110 combo with S* ecu & trigger wheel timing mod advanced 2deg

 

quote:Originally posted by Frankenstein

Lower compression - yes - just a touch but also more displacement


Correct me if im wrong but isnt displacement (bore * stroke)?
since you have changed neither, the displacment shouldnt be effected


chamber volume is raised slightly, but this doesnt not increase displacement

other wise using your theory, HC pistons would change the displacement as well, since they change the combustions volume

the only way to change displacemnt is to change bore or stroke....

otherwise, this is an excellant write up, and i agree with cadman, i dont understand why more people dont have thermal coatings in there engine

 

hey oli, how r u bud?
question bout ur double head gasket mod. i too have the pingin, only under load in higher gears, been using good vpower 93oct. gas from shell, and i have been trying different octane boosters as well, i do have a custom map, everything is fantastic cept for highway runs in higher gears when i crack the throttle, that is when it occurrs. i do have 2 sets of pr 110 head gaskets (bout 30thousandths each). had my cylinders cut to 0 deck height, that's when the pinging occurred. i was wonderin do i need to use the xtra head gasket cuz it is a 3 layer gasket (approx. 30thousandths of an inch in total) or should just a 10thousandth of an inch base gasket would work just as good and not come down too much on the higher compression to totally defeat the purpose of 0 deck height? u follow me????
only thing is, i would have to remove the cylinders and have someone help me get the pistons back in as opposed to only takin the heads off to put another gasket on.. would a thinner single one piece (10thousandth of an inch) gasket added on to the one single (30thousandth 3 piece) be just enough to stop the ping? if so, i would rather go that route. soo, please, tell me ur opinion on this...
i will prolly do either one, but if short cut is available to get the same results, i would most definitely take that route....
anyways, have a good one....[/emoticons/emotion-1.gif]
james[8D]quote:Originally posted by Frankenstein

Here is a little writeup on a mod that will cure the high compression ping of any Warrior:

http://www.fxstein.com/blog/index.php?op=ViewArticle&articleId=52&blogId=1

Ask 357Warrior about his Warrior feels after this recent mod.

 

We did the head gasket because of the very same issue. Its the easiest mod as only the heads need to come of. Ad 1 extra and you will not see any more ping. I am running 2 of the 110 head gaskets on the turbo for the past two years without any issues.