| Author |
Message |
'75 308 GT4 (Peter)
Advanced Member
Username: Peter
Post Number: 2812
Registered: 12-2000
| | Posted on Tuesday, June 03, 2003 - 2:50 pm: | |
My pointers on velocity-stack shape?
"Scientific Design of Exhaust & Intake Systems, Third Edition" by John Morrison & Philip Smith, Bentley Publishers, 1971 reprinted in 2000.
Its somewhere in there... |
'75 308 GT4 (Peter)
Advanced Member
Username: Peter
Post Number: 2811
Registered: 12-2000
| | Posted on Tuesday, June 03, 2003 - 2:44 pm: | |
Rob S.: "...Honda builds one of the highest specific output naturally aspirated engines in mass production."
True, but only in mass-production. Caterham does build an engine with greater potential that is used in their R500. Utilising a Rover K 1.8 as a base, they eventually get 230BHP out of it (= 128BHP per litre) |
Rob Schermerhorn (Rexrcr)
Member
Username: Rexrcr
Post Number: 641
Registered: 11-2002
| | Posted on Tuesday, June 03, 2003 - 2:33 pm: | |
Mitch, post this question here: http://www.theoldone.com/forum/forum.asp?FORUM_ID=1
You'll have to register first. I practically guarentee you'll get an answer.
While you're on this site, check out the archives. Hours of reading here for you. I know a lot of it is Honda/Acura, but an engine is an engine, plus, Honda builds one of the highest specific output naturally aspirated engines in mass production. |
James Glickenhaus (Napolis)
Intermediate Member
Username: Napolis
Post Number: 1504
Registered: 10-2002
| | Posted on Tuesday, June 03, 2003 - 2:15 pm: | |
Mitch
I don't know why but on the P3 (Webbers) the stacks are straight. On the P4 (Mech FI) they are curved. On the P3 they are upright, on P4 sideways.
Best
Jim |
Mitch Alsup (Mitch_alsup)
Member
Username: Mitch_alsup
Post Number: 723
Registered: 4-2002
| | Posted on Tuesday, June 03, 2003 - 2:11 pm: | |
I've done over 20 hours of net research on velocity stacks, but I can't seem to find out how to compute several features.
1) how does one compute the 'shape' of the high pressure pulse that bounces off the back side of the closing intake valve? This has to be a function of the maximum intake air/mixture velocity, and the closing rate of the CAM, plus some shape data from the inlet itself.
2) How does one compute the 'shape' of the negative pulse that reflects off the horn section of the velocity stack? This should be a funciton of the horn shape, and the area of the pipe before the horn and the expansion rate of the horn itself.
3) Does the returning negative pressure pulse bounce off the closed valve face without changing 'shape'? Simple pressure reflection?
4) and the 'shape' of the resulting positive pressure pulse after a second reflection off the horn section. Thereby computing the 'shape' of the pressure pulse that arrives just as the intake valve reopens.
I have found all the math to descrive various shaped horns (exponential, negative exponential, bessle) from the music and speaker industries, but these are all frequency domain equations. I would like to be able to compute these function in the time domain to visualize what the size, and shape of the velocity stack do to the power band of an engine.
Any pointers would be welcome. |
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