Some Thoughts On Slant Geometry

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OK, then just grind the crank pins differently. But your 198 crank would certainly be more square. Why is this important? Just curious....

And BTW, the KB268 and 259 2.2L pistons work out pretty close to zero deck the pistons top with the L6 rod and the 170 block. They would stick out by around .023" with no mods. The pins are off by about 0.026" so the pistons pin bore needs enlarging or the rods rebushed. This is all off-the shelf parts.....And no, I don't have these in hand to check further. Just throwing out thoughts on the theme of lower rod/stroke ratio, which seemed to be desired to get fill velocity up at the lower RPM's.
 
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nm9stheham said:
And BTW, the KB268 and 259 2.2L pistons work out pretty close to zero deck the pistons top with the L6 rod and the 170 block. They would stick out by around .023" with no mods. The pins are off by about 0.26" so the pistons pin bore needs enlarging or the rods rebushed.
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Now that's good information!
 
You're welcome.. and I threw in a bit more verbiage in my last post... noting important, but I was wondering why square was that important. We were posting at the same time LOL

Ooops, time to go out and buy cat food.....and think more about what might be banging in my son's 340 after we changed rocker sets.... It's always sumpthin'!
 
Oh dang, I forgot....the 2.2L pistons' deck height number was based upon crank pins machined for max stroke with the L6 rods.
 
barbee6043 said:
that 61 lancer listed in records at Asbury, Mo is local car from Carthage mo. rumor has it that it has a heavy custom flywheel and $14000 in engine. runs NA. pretty cool. I image the details are top secret!
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Is that an offer or a rumor? Since you are less than 50 miles from me, I'll even pay for your fuel to come get that $14,000.00 engine. I might even take less money than that for the engine since that is more than I have invested in the whole car.
No secrets here. Slant Six Racing News #28 pages 14-26. tells everything about the car and the engine, even the cam specs and how it ran 10.50's on 30% nitro. Talks about the used BBC lightweight flywheel with the hogged out mounting holes to slant 6 pattern and how it has an 130 tooth MoPar starter ring adapted to it.
The Lancer is the quickest N/A car around for the weight class and has been for about 18 years. That pretty aluminum head engine must not run as good as it looks because over 15 years ago the owner told me they were going to be the quickest N/A, hasn't happened yet.
3.530 bore with a 7" rod, 4.125 stroke. Was 4.200 stroke but leaving at 6200RPM with a manual transmission twists crankshafts after 60-70 runs so we went to a stock stroke with no problems. Block is filled to the deck and just cool the head. Homemade intake with 2" Hilborn throttle bodies, mechanical fuel injection. Dry sump oiling and crank trigger ignition.
I would like to keep the engine until after the Tulsa MoPar race Nov. 5th, just email me and I will get it pulled out after that.
 
Mark's Lancer is one I have been looking at for a while, even though we are doing completely different things.
Much of what he is doing proves out my theory. Alcohol, at 2.2 times the volume of gasoline provides a very long duration burn.
The 30% nitro is within the outer limits of what can be run through an alky system, and is enough to extend the duration another couple of degrees.
Think of it this way...and only using round numbers to illustrate the idea.
Gasoline alone will work the piston at maximum pressure from TDC to 25 ATDC
At that point, the piston starts to run away from the diminishing pressure pulse.
Alcohol will extend the duration to 30 ATDC.
30% nitro, because it is acting as a retarding agent for the alcohol will extend that another 5 degrees.
In his example, all of this is happening up in the 6-7000 rpm range. With the long rod, the piston "thinks" the engine is spinning at half that speed.
So, at a total of (again, just round number example) 35 degrees effective pressure pulse per total volume of fuel in the chamber, if one was to shorten the rod, piston speed would increase, but total time for the event would decrease. The duration of burn would be more effective for more degrees of crankshaft rotation. That equals torque.
That long rod, 4.125 stroke combination would be a complete monster on 80-100% nitro. The resistance of that stand up rod geometry would provide the load nitro needs for efficient light off, and with the volume of fuel it could use at the higher percentages, duration of burn would be way past where the exhaust valve opens.
 
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Just as a general comment to add: The actual effect on torque is more than just the duration of the burn; even if you extend the burn time of the same amount of fuel energy, then the combustion pressure will be lower (since the fuel is burning more slowly) and the net effect over a longer duration can go either way.

I am not sure I am understanding this:
whitepunkonnitro said:
So, at a total of (again, just round number example) 35 degrees effective pressure pulse per total volume of fuel in the chamber, if one was to shorten the rod, piston speed would increase, but total time for the event would decrease. The duration of burn would be more effective for more degrees of crankshaft rotation. That equals torque.
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So are you saying that you think that the effective, or net, torque output will be higher, since the pressure will act more effective even though it is a shorter time?

I have been assuming you are looking at a short rod to get higher piston velocity at lower RPM's for better cylinder fill there, and giving up the higher RPM end a bit, to better match the head. Yes? No?
 
nm9stheham said:
Just as a general comment to add: The actual effect on torque is more than just the duration of the burn; even if you extend the burn time of the same amount of fuel energy, then the combustion pressure will be lower (since the fuel is burning more slowly) and the net effect over a longer duration can go either way.

I am not sure I am understanding this:

So are you saying that you think that the effective, or net, torque output will be higher, since the pressure will act more effective even though it is a shorter time?

I have been assuming you are looking at a short rod to get higher piston velocity at lower RPM's for better cylinder fill there, and giving up the higher RPM end a bit, to better match the head. Yes? No?
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The faster piston speed/cylinder fill is a byproduct and not the main event. I mainly want the shorter rod for increased angularity in the early degrees of rotation away from TDC.
 
Ah, OK, for better torque angle.... got it. Which is part of what strokers do... I'm still curious why the 'squareness' is important here.
 
I have gotten a 1.49 60 ft with a auto NA.I run 28 timeing,anything higher and car slows down.Got a 1.44 60 ft with a 80 shot and timeing at 26.
 
slantracer said:
Is that an offer or a rumor? Since you are less than 50 miles from me, I'll even pay for your fuel to come get that $14,000.00 engine. I might even take less money than that for the engine since that is more than I have invested in the whole car.
No secrets here. Slant Six Racing News #28 pages 14-26. tells everything about the car and the engine, even the cam specs and how it ran 10.50's on 30% nitro. Talks about the used BBC lightweight flywheel with the hogged out mounting holes to slant 6 pattern and how it has an 130 tooth MoPar starter ring adapted to it.
The Lancer is the quickest N/A car around for the weight class and has been for about 18 years. That pretty aluminum head engine must not run as good as it looks because over 15 years ago the owner told me they were going to be the quickest N/A, hasn't happened yet.
3.530 bore with a 7" rod, 4.125 stroke. Was 4.200 stroke but leaving at 6200RPM with a manual transmission twists crankshafts after 60-70 runs so we went to a stock stroke with no problems. Block is filled to the deck and just cool the head. Homemade intake with 2" Hilborn throttle bodies, mechanical fuel injection. Dry sump oiling and crank trigger ignition.
I would like to keep the engine until after the Tulsa MoPar race Nov. 5th, just email me and I will get it pulled out after that.
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I did have the record in that weight class for several years,so it wasnt 18 years in a row.Havent gotten car back together since crash but I will and will try to get that record back,but Marks car is a top notch high tech work of art.
 
Tony - I think the engineering is sound - but the issue will always be the head arrangement and lack of potential. What you propose, at least in my head at 10pm on a Sunday, will simply put you in the "not enough port" zone earlier. It might hit harder, yes. But it won't run out as far. If I understand you - the 170 platform might make better use of the head but you still run out of air at some point. If it was me I'd probably gear it to get past the low speed issue, and run a transmission with enough gears to keep it between that low speed issue and running out of port. Rather than sciencing further on the engine, science out more downstream in the powertrain...
 
Shhhhh..... let him do it and let us know! Free R&D ! LOL

I am not so sure that there won't be a benefit from making the cylinder filling better at the lower RPM where the head can still work. Basically, the thought of making it a better operating match for the existing flow range. I have always assumed that is why the long hyper intakes worked out..... (but that is an assumption...)
 
madmax/6 said:
I did have the record in that weight class for several years,so it wasnt 18 years in a row.Havent gotten car back together since crash but I will and will try to get that record back,but Marks car is a top notch high tech work of art.
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Glad to hear you are moving along and will be back racing soon. You are right about the gas record, I should have been more specific on the record which is B/A that we have had a long time. The pictures of your car show that you are a true craftsman.
 
nm9stheham said:
Shhhhh..... let him do it and let us know! Free R&D ! LOL

I am not so sure that there won't be a benefit from making the cylinder filling better at the lower RPM where the head can still work. Basically, the thought of making it a better operating match for the existing flow range. I have always assumed that is why the long hyper intakes worked out..... (but that is an assumption...)
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He can correct me if I'm wrong, but I read this post as Tony is talking about flame propagation and the effect on the position of the crank at peak pressure. He wants to change the parts to adjust the timing (angle) to better suit the low rpm. That's not cylinder filling. What I'm tossing in the mix is that cylinder filling is more important, and will still be limited.
 
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