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mightymouse Samba Member
Joined: May 26, 2004 Posts: 4220 Location: las vegas
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Posted: Wed Sep 16, 2009 8:33 pm Post subject: |
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Very good post.
Do realize that what you said will blow completely over 90% of peoples heads.
There is ALOT more variables to building an engine, BUT you at LEAST need to match the compression to the cam on a basic level. At the start of your build. Thats what im trying to say.
You dont put FK87 and 7.6 to 1. Thats simply absurd.
You know what im saying, but you are doing what i often do, and over info'ing people. To the point that they give up, and just stick with billy joe bob because his low compression 1835's been running forever.
All im trying to say is, get people to think outside the box thats first step. THEN once they have headed down the right road they will expand their knowledge. And if they care as much or you and I, about advancing as both a person and engine builder, they will someday get to what your talking about, at the their own pace.
Blow em away, and you look great, but they never even try. _________________ Nothing can stop the man with the right mental attitude from achieving his goal; nothing on earth can help the man with the wrong mental attitude.
Thomas Jefferson
Note to EVERYONE.
Know your ZDDP levels or you WILL lose a cam and lifters. |
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jeff68 Samba Member
Joined: November 02, 2007 Posts: 298 Location: Sarasota, Florida
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Posted: Thu Sep 17, 2009 5:12 am Post subject: |
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Stripped 66 & Mighty Mouse: Very good information in your post(s), I appreciate the time you have taken in understanding these engineering concepts, applying them and stating them here. You rarely see forum members posting scientific engineering principles to back up their claims and preferences. Many times it’s just someone carrying on and letting their ego get the best of them. I agree with what you are saying about the dynamic process in the combustion chamber, and the changing / even unknown variables within the combustions chamber at different rpm’s and how they are affected by cam timing as well the quality of the air fuel mixture in the chamber. I also understand that because there are so many variables that to test a concept or design and really find out if something works is to try it out. It sounds as though both you and Mighty Mouse have done just that and have had success with it and that’s great. I wish I had more time and money (mostly $$$$!) to experiment with some things but at this point I don’t. at this point I had the money to build one engine and it was built with a specific use, longevity and performance in mind. For me the performance of the motor isn't just a peak horsepower number. It was not built to “push the envelope” but to perform well and also live on pump gas. I wanted to “have it all”. Since I have not built and run an engine with higher compression ratio I personally can’t say if it works well or not and if I gave that impression It’s not what I intended. My main points were to point out that a low compression engine can make great power and that a specific Octane of fuel has thermodynamic properties that I feel limit it to a certain compression ratio.
Thanks Mighty Mouse for the props on my engine. My engine is in fact a Berg engine and the heads are not off the shelf CB044 heads but are 870 style and have been massaged a bit by the Bergs, with both CNC and hand porting. Interestingly enough they were done quite a few years ago when CNC porting was realtively new to the aircooled VW world, but they work very well. Take care and good luck with what you are doing I look forward to reading more of your posts. |
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CombatBus Samba Member
Joined: October 17, 2009 Posts: 307 Location: reno
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Posted: Fri Oct 23, 2009 7:38 pm Post subject: |
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wow at this tread. just a quick bit of info on some non vw data i ran a car with stroked engine with 1.62 ratio rods and 13.4:1 compression and a custom ground cam. it railed and ran cooler than stock head temps usually. this was all done on 91 peetane pump gas. its called tuning people now say it with me T-U-N-I-N-G. anything is possible you just have to set things up to do what you need them to mechanically then make sure you have the proper tune to back those parts up. if not then things go boom and you learn for next time so you go faster. _________________ I am the wisest man alive, for I know one thing, and that is that I know nothing.
Socrates
Da bus! 71' deluxe dyno'd 154whp 153tq with large heads SOLD
http://www.thesamba.com/vw/forum/viewtopic.php?t=382960
77' SC one cab 2 peeps tons o stuff type 4 SOLD
http://www.thesamba.com/vw/forum/viewtopic.php?t=421432 |
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CombatBus Samba Member
Joined: October 17, 2009 Posts: 307 Location: reno
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Posted: Fri Oct 23, 2009 7:47 pm Post subject: |
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oh and one more thing shall i even state what insane combo's/ign. timing/compression we could come up with if we introduce say a bit of water injection on a vw aircooled engine, or even better yet a bit of methanol. _________________ I am the wisest man alive, for I know one thing, and that is that I know nothing.
Socrates
Da bus! 71' deluxe dyno'd 154whp 153tq with large heads SOLD
http://www.thesamba.com/vw/forum/viewtopic.php?t=382960
77' SC one cab 2 peeps tons o stuff type 4 SOLD
http://www.thesamba.com/vw/forum/viewtopic.php?t=421432 |
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audiman72 Samba Member
Joined: January 19, 2007 Posts: 47 Location: Salinas Ca 93906
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Posted: Thu May 23, 2019 1:15 pm Post subject: |
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mightymouse wrote: |
vwracerdave wrote: |
That is a total mismatch combination for a street engine.
heads too big
cam too small
header too large
roller tip rockers don't belong on street cars
way, way, way too much compression |
Im surprised to hear you of all people saying this BS.
heads are fine, NOT too big.
Cam does need to be bigger
Header wont be too big once you adjust stuff.
roller tip rockers are fine on street cars run em FOREVER 0 problems.
No such thing as too much compression.
compression needs to match the cam. PERIOD.
Wanna run pump piss, fine, just back your timing off couple degrees and cruise all week. Then on race nites or when you go hunting, grab some real fuel and set it where it makes best power. (dyno it)
So id say
Step#1 sell the IDFs buy IDAs
Step#2 order cam, say..... web 86c
Step#3 have case and heads cut, get 94s.
Step#4 dont change a thing with the compression, 11-11.5 to 1 will be perfect with 86c.
Step#5 sell those stubby rods to someone with a 74mm crank. Get 5.7s or 5.8s
def run those sweet rockers. me likey them. zero lash cold.
Need any advice, Pm me. stay away from the compression fearing masses, they are like religious wackjobs, nothing they say makes sense.
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Great point of view MM! _________________ There are those who have, those who will, and those who will lie about it. |
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Sigurd Samba Member
Joined: April 18, 2006 Posts: 2639 Location: Rockford, IL
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Posted: Thu May 23, 2019 6:45 pm Post subject: Re: 2110cc horsepower? |
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Almost 10 years later... |
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