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Arouse the DAMPFHAMMER!
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5,684 Posts
Discussion Starter #1 (Edited)
Hi Guys,

after some hours of designing my 86.5x86 engine project (Status quo: replacement engine is here, engine and component builder are choosen, stock list is not everywhere fixed) I thought to do a engine build thread...one a bit different :D.

I am aware of I am here in the lion's den of practicans, developing impressing engines by real testing, I was in the meaning it wouldn't be very smart to report about my more theoretical approach before one screw of the engine is touched. So I decided to turn the tables and do a guessing game with you, sponsered by my won bet with BlackNDecker (s. here).

What's the task for you in that guessing game?
You just have to guess the power and torque of the below presented setup in the following form: xxx whp/ xxx wlbft (xxx = your guess).

Winnings by placing a guess
Winings start values: 1st is $50, 2nd is $30 and 3rd is $20.

What is the process of the guessing game?
  1. I will more concrete the engine setup and background to the build step by step within the game space
  2. I will present weekly the actual statistic of guesses (diagram based)
  3. Every day I will reduce the win budget by 1 $
  4. Win calculation = (1 - days / 100) x winnings start value, e.g. win of 1st place on 30th day = $35
  5. Rest of money not paid off will be donated anyway for "www.sos-childrensvillages.org", an aid group for kids and youths of families in need
  6. One person can place only one guess
  7. One guess looks like this: xxx whp/ xxx wlbft, Edit, 12/21/2015: if "w" is missing in your post, I will add it in THE list!
  8. Who wins? First come, first serve (minimum condition for both guesses is +-4 %)!
  9. Only guesses of K20a.org members with more than 101 days membership are accepted
  10. Proven scammers guesses aren't accepted
  11. Payment will be done via Paypal, winner has to post the win receipt in this thread
  12. Start of the guessing game is now (20th Dec. 2015, +1 UTC 14:58)!
  13. Power and torque (wheel based) result will be presented after the end of the game when engine was dyno'd.
  14. Dyno results will be corrected according DIN 70020.
Good luck and have fun in that 86.5x86 rebuild question guessing game!

Markus



Edit (02.07.2017): I did delete my Photobucket.com library, because they blackmailed free account users to pay for it or to loose the library links.

Edit (20.08.2017):I am sorry you can't see the photos at the moment. If you have a special interest in one of them, please let me know it, I will search for it and post it in the origin post once again.
 

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Arouse the DAMPFHAMMER!
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5,684 Posts
Discussion Starter #7
2nd day = $99 in the pot

Thanks guys for your guesses! You are toughest ones of all! Up with your guesses in the list :D.

260whp 170ftlbs
2nd day -> $99 based
250hp 167tq
2nd day -> $99 based

You guys are the real gamers :up: :D.

A note:
I will take every guess as wheel based, if there is an indicator "w" or not. Otherwise I would type to much letters for clarification. Thanks

Markus
 

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Arouse the DAMPFHAMMER!
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5,684 Posts
Discussion Starter #9
Fourth hint: cam design

Im guessing cams will be stock or chosen by the desired peak hp rpm?
Good question CARFROG!

For the direct answer it is too early in the guessing game, but let me give you a fourth hint. You find it in my 2nd post by combining two informations :D.

The next days I will report about my development tools, to give you an idea about possibilies with those. Further hints all around but hid :D.
 

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Arouse the DAMPFHAMMER!
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5,684 Posts
Discussion Starter #11

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Arouse the DAMPFHAMMER!
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5,684 Posts
Discussion Starter #13 (Edited)
Sixth hint: Torque design process for engine setup

The torque curve TFlw(n) or shape of that engine has a certain goal shape, which was done through a iteration process of the following design process :D.


Background, the engine is designed for a certain purpose, e.g. hill climb racing. To have optimal engine setup, all requirements like track layout, track time goal t0, chassis weight, gear box ratio's and so on are fed into a Dynamic Chassis Model, which will tell one the resulted track time for a specific torque curve and engine speed range. Of course the model incooperates all drag forces of the chassis, which has to be calibrated first within a measurement process of that specific car. This can be done independently of a specific engine setup.

The 1D Engine Simulation Model is integrated in that process to calculate the design of the engine setup parts, e.g. like the intake manifold, which is needed to reach the time goal for a certain track.

Finally, the above described process returns an engine setup, which fullfills the notified track time goal through a certain torque shape. The torque shape result now can be interpreted as a power curve via

power = torque x 2 x pi x engine speed.

The engine of that guessing game was designed like described above for a hill climb application.
 

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Arouse the DAMPFHAMMER!
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5,684 Posts
Discussion Starter #14
Seventh hint: header

Ok, the header will be designed by me and fab'd by someone hwo know his stuff.

Actual header design specifications:

Because of the very small enginebay clearances of the chassis the header (s. "Reference" in the guessing graph) has 380 mm long and OD Ø48 mm runners which are merged together via 4-1 conjunction into the CAT (200 cpsi, Ø110x130 mm)

New header design specifications:

  • support a constant BMEP (+-0.5 bar) from 4.5-8.0 krpm
  • support a VTEC point at 4.5 krpm
  • incoorperation of a CAT is a must*
  • chassis is a '02-'04 EUDM Lotus Elise
  • compartement should stay
  • ...enough for today :D
*Emission test limits:
 

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275 whp @ 7500 rpm's/ 195 wtq @ 6800 rpm's

What's your gearing like?? Short geared for hill-climbing no??
4spd/5spd??
No real need to top-rev the engine... short crisp curves and accelerating??

Mounty
 

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Arouse the DAMPFHAMMER!
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5,684 Posts
Discussion Starter #17
What's your gearing like?? Short geared for hill-climbing no??
4spd/5spd??
Gearing is like standard Y2M3 (6 speed), but final drive will be adapted according to the results of the process described in post #13.

...No real need to top-rev the engine... short crisp curves and accelerating?
That's an interesting thesis. It depends on the character of the engine, I mean on the torque curve shape. OesRecords found a very interesting FI solution


My way is NA :up:.
 

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Arouse the DAMPFHAMMER!
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5,684 Posts
Discussion Starter #18
Engine comparison - BMEP (break mean effective pressure)

Happy new year, guys!

I did a comparison of your guesses to some other engines and the reference (= actual engine) concerning BMEP level for peak power and peak torque.

For those who don't know about BMEP, first this is THAT parameter engine to compare reciprocation engines. It tells someone about the engine capacity to do work during one working cycle. BMEP is torque related like the following equations shows:

BMEP = Torque x i x 2 x Pi / displacement, i = 2 for 4 stroke engines, 1 for 2 stroke engines

So the bigger torque at a specific engine speed (= tuning and modifing), the bigger is BMEP. Or the smaller the displacement for a certain torque (= downsizing), the bigger is BMEP. From that, you can imagine, the more air the engine sucks by one cycle, the higher is BMEP.


I did use torque from peak power and peak torque for the graph above. You find in the graph the stock RSX engine, which has an already high BMEP near to the (12,12) bar corner. The K20A2 (Reference) with I, H, E is a big step forward in terms of peak BMEP of around 14 bar! The 2011' GT3 RS 4.0 engine (500 PS/450 Nm) is not that much better :D. The area's of your guessings is in the range of an Formula 1 V10 engine, an engine which occupied about 20+ engineers for at least 1 year! This BMEP area is great challenge to overcome, but K-series basis has much more potential :D...just see e.g. SickSilvers_ep3 drag engine, which break through areas of stock turbo charged engines like the SRT-4 2.4 liter engine!

The Formula 1 engine is a bit misplaced in the graph, as it revvs more than twice of an K-series engine or any other engine in the graph. Why? BMEP includes the friction of crank assembly, this friction work, called FMEP (friction mean effective pressure), is more than 3 times compared to an 8 krpm operation point.

So what would be righteous? This parameter is called IMEP (indicated mean effective pressure), it is calculated by

IMEP = BMEP + FMEP.

With that said, it is clear the Formula 1 has a much higher IMEP ([email protected] krpm ~ 7-9 bar) as those of your guessings, even higher compared to SickSilver_ep3 engine ([email protected] krpm ~ 3.0-3.5 bar)...so, the work of the 20+ engineers is still of value :D.
 
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