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well, you could change the wrist pin height, and avoid all the other problems, but what I'm getting from you is 1198 crank and rods, 1098 piston/cyl, 1098 heads, with 1198 cams?...
 

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Discussion Starter #23
interestingly, the 1098 makes more power per liter than a 1198 stock for stock; so I don't expect to see MAJOR lift-duration differences, as the extra power might just be the increased displacement. I understand that everything has to work in together to get good power, so changing only one parameter is not the absolute solution.
1098: In 253/11.7mm Ex 260/10.7mm
1198: In 259/12.7mm Ex 260/11.7mm

Its harder to get good litre power from a bigger capacity.
 

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Discussion Starter #24
No, that it is KISS. But not by everyone's standard.
Im thinking KISS is when you keep it as simple as possible in all steps involved, how many steps there are can be subject to KISS aswell if you choose the steps in a fashion they together form the most simple pattern possible for the specific task, but thats just my take on it :)
Task here included spliting the engine, no way around that.
 

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Discussion Starter #25 (Edited)
.... using the same KISS principle what would you change on this engine for a dedicated track bike?
For a race bike I would calculate intake optimum gas velocity for a higher RPM and retard the intakes further, basically move up the RPM range. But low revs is good for longetivity, so for a trackday-no-racer Id probably recommend the same as this street bike.
R-cams if wallet allows.

Edit: For the race version Id also move power peaks back closer to original by mounting 20mm shorter stacks as they get pushed down by the bigger displacement. At this point KISS is out the window haha.
 

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TomTom thanks for sharing and I see your logic and agree with the suggestions offered regarding practical useful increases in power and torque with simple (ish) mods
 

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HP per litre is a simplistic and unrealistic measure of an engines worth. It tells you nothing of of the engines drive-ability. Tom is right in saying more power at lower rpm is better for most track day riders.
Increasing capacity generally doesn't doesn't give you big top end but it does give a broader, more user-friendly power delivery. If you put a data logger on your bike, you would be shocked at how LITTLE of all that HP you use. For a track day rider I would steer someone in the direction of learn to ride what you have if you want to beat your mate on his 600. On the other hand, power, and excess of power is sooooo much fun.
What is worrying for me is I perceive the evo as a not very robust engine mechanically. Cracked pistons, cracked cases, spun big-ends and cracked cases. Not seen this in the 998/999 range. Is it because there are more EVO's out there being thrashed, or are they just a soft motor? Not a huge change in design from the base gasket down compared to the 999, but a BIG increase in torque.
In a nutshell you can fuck around with cam timing and big exhausts (and it's fun to learn) but at the end of the day 160 is MORE than enough HP for fast lap times for the track day rider and not to much stress on the engine. Or the brain.
 

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Honest opinion wanted - I bought a 1198 engine I'm currently rebuilding to put in my 1098. But this scenario you've introduced intrigues me. From your stand-point would I be better served modifying my current 1098 engine with the 104mm pistal exception by these means OR continue with my complete engine replace?
 

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Would be interesting to see a longevity test with these engines. At some point I'm going to build the special 999 with whatever engine that gives power, torque and longevity for reasonable price,
 

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Thanks Tom, please keep posting even when crap get thrown your way..
 

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Tom, just from what you have related, swept volume is more important, than peak numbers, as it relates more to USABLE HP (torque) than a dyno brag sheet...

and timing is everything...
 

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Swept volume has nothing to do with peak. Swept volume is piston displacement from TDC to BDC. And it isn't that easy. Cam timing, pipe length and diameter, valve and port size and intake tract length ALL Play their roll in peak HP and how it's delivered. It's all a balanceing act, and, within reason, there is no perfect or even optimal set up. Didn't mean to push in to answer a question directed for Tom.
 

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Discussion Starter #34
Would be interesting to see a longevity test with these engines.
In my eyes its all down to how it will be used, if you ride it like a normal 1098 it should last just as long, if you race it then race limits it is. One of the ideas with using stock bits is you dont have to worry about special parts at inspection/rebuilding.
 

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Discussion Starter #35
Honest opinion wanted - I bought a 1198 engine I'm currently rebuilding to put in my 1098. But this scenario you've introduced intrigues me. From your stand-point would I be better served modifying my current 1098 engine with the 104mm pistal exception by these means OR continue with my complete engine replace?
Difficult question as you have so many options. The rebuilt 1098 will be more powerful than a stock 1198, but again that can be tuned too :)
Sell the 1198 and put the money into the 1098 rebuild is one option.
 

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bumping an old thread.

1198 cam and crank and not easy to get by. Thinking of buying a 1198 engine and rebuild it VS rebuild my 1098....
 

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I have a full set of 1198 cams lying here on the shelf :)

Did another 1098 engine at 1154cc with 1198 cams and it did 134Nm and 171hp (SAE), will do another 1154 soon with a ben fox:ed crank and R cams.
I have an 1198 motor where the cam seized I polished the cam and it's fine not so much for the head it has pretty deep scoring want to put a set of 1098 heads and use my 1198 cams is this also possible just want to make sure as you have used the 1098 bottom end
 

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I have an 1198 motor where the cam seized I polished the cam and it's fine not so much for the head it has pretty deep scoring want to put a set of 1098 heads and use my 1198 cams is this also possible just want to make sure as you have used the 1098 bottom end
This may be possible to repair using a high end epoxy metal such as Decon.
 
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