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RE: Doubled my fuel economy! - 10/2/2007 2:18:44 PM   
lsurber


 

Posts: 251
Joined: 6/22/2007
From: Fort Worth, TX, USA
Status: offline 		I would still use the radius cut because of strength and the fact that it is the only type of SPI port that is working properly on the above engine. This engine has been running great and refuses to stall with no high/low idle problems at all!

< Message edited by lsurber -- 10/2/2007 2:19:34 PM >

(in reply to j_blaze)
       Post #: 176

RE: Doubled my fuel economy! - 10/3/2007 5:10:32 AM   
lsurber


 

Posts: 251
Joined: 6/22/2007
From: Fort Worth, TX, USA
Status: offline 		Ok, degree'd the SH engine with erratic idle! Here it is!

Crank induction: open=210, close=40, Duration=190
Intake: open=100, close=260, Duration=160
Boost: open=100, close=260, Duration=160
Exhaust: open=90, close=270, Duration=180
SPI: open=328, close=32, Duration=64
Case Pos. Pressurization: Start=32, End=180, Duration=148
Case Neg. Pressurization: Start=180, End=328, Duration=148
Combustion Pressurization: Start=270, End=360, Duration=90

Notice: Look at the induction close point vs. SPI close and you will notice 8 degrees compared to 14 for the good engine! I will first increase Crank Induction close point to match that of the good engine then test. After that the only other change would be to extend the SPI duration. I will make these changes over the next week so stay tuned! We are almost ready to silence the critics!

I had to edit this post because I found an error, sorry!



< Message edited by lsurber -- 10/3/2007 3:41:43 PM >

(in reply to lsurber)
       Post #: 177

RE: Doubled my fuel economy! - 10/3/2007 2:56:04 PM   
SManMTB



Posts: 4755
Joined: 4/28/2005
From: Charlottesville, VA, USA
Status: online 		Great! So now we can all get a video of 18 min run time on a tank.

(in reply to lsurber)
       Post #: 178

RE: Doubled my fuel economy! - 10/3/2007 3:51:39 PM   
lsurber


 

Posts: 251
Joined: 6/22/2007
From: Fort Worth, TX, USA
Status: offline 		Once the timing issues are ironed out I would do this mod more because it REFUSES to stall even after extended high speed runs! Every other engine I have seen without this mod would stall when throttle is lifted after such abusive lean-out pulls!!!!!

The fuel economy is just a bonus!

(in reply to SManMTB)
       Post #: 179

RE: Doubled my fuel economy! - 10/3/2007 8:26:00 PM   
Anthoop



Posts: 1058
Joined: 2/3/2007
From: , UNITED KINGDOM
Status: offline
quote:

ORIGINAL: lsurber
The fuel economy is just a bonus!

A bonus to....less maximum power!
Be it noticable or not the mod will reduce engine power.
Quite often i see offers from companys(with dynos)letting you send a motor for testing,maybe it would be good but then all that talk was oohh pages ago.
Think i'll just stop posting here,just read and smile from here on in for me.


_____________________________

When I die, I want to go in my sleep like my grandfather,not screaming
like the passengers in his car at the time.

(in reply to lsurber)
       Post #: 180

RE: Doubled my fuel economy! - 10/3/2007 9:09:20 PM   
lsurber


 

Posts: 251
Joined: 6/22/2007
From: Fort Worth, TX, USA
Status: offline 		I personally feel that most engines offer more than enough power to win races! This thread was started to learn about economy mods. There have been numerous threads on RCUniverse with questions on how to increase runtime! This mod has proven to me that it is indeed possible to get more runtime, sacrifice little overall power, and susbtantially improve the thermal stability of a modern engine.

Maybe you shouldn't post in this thread anymore if you are so negative and do not want to contribute anything worthy!

(in reply to Anthoop)
       Post #: 181

RE: Doubled my fuel economy! - 10/4/2007 1:43:50 AM   
j_blaze



Posts: 1424
Joined: 1/4/2007
From: Tampa, FL, USA
Status: online 		i don't have a dyno but i think i had an increase in power. i can land the buggy in spots i could only land it with 30% with high temps. it could just be the engine coming alive on its third tank now or the different piston sleeve. now with 20% it can get there and stay cooler, just gotta figure out the quitting.

_____________________________

Hyper ST PRO - RB WS7III/RB S5 L2G, JR, DX3R
Cen Matrix PBS - RB S3II/STS D21B (JBModz), Ace

(in reply to lsurber)
       Post #: 182

RE: Doubled my fuel economy! - 10/4/2007 3:32:32 AM   
duckedup


 

Posts: 2680
Joined: 1/24/2006
From: Portland, OR, USA
Status: offline
quote:

ORIGINAL: Chevy-SS

This is a very interesting thread. I would be very interested in trying something like this, but for the time being, I think I would rather try some of the simpler more proven methods.

For instance, it was mentioned about the small slices in the head. This is something I would really like to do and I would be much more comfortable starting with the mod like this. Can someone provide me with a hyperlink or some directions as to how to do the small slices in the head?

Thank you all for the interesting read, and I would be most excited to see some actual proof of this mod.


The head button mod? attached are couple pics of what it looks like (one persons version)... I only did one cut on mine, though, and it faces the exhaust port (still kind of experimenting with it..) I've read you can face it towards the boost, or the exhaust, or both - just like everything else, not everyone agrees, so it's trial and error for me! lol..


This seems like an interesting mod here (economy mod), I'm looking forward to reading more feedback



Attachments
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Click for fullsize 		Click to see fullsize image.
Click for fullsize

(in reply to Chevy-SS)
       Post #: 183

RE: Doubled my fuel economy! - 10/4/2007 4:55:24 AM   
lsurber


 

Posts: 251
Joined: 6/22/2007
From: Fort Worth, TX, USA
Status: offline 		The headbutton mod probably has more to do with reducing compression than it does directing burn.

I am almost there Blaze! I believe by next week I will have a fix for the erratic idle. It will probably involve using a degree wheel and modifying crank induction timing! Do you feel up to it?

It would be a good idea if you were to degree your engine and post results here. The most important measurements are crank induction and SPI timing marks.

(in reply to duckedup)
       Post #: 184

RE: Doubled my fuel economy! - 10/5/2007 1:22:53 AM   
j_blaze



Posts: 1424
Joined: 1/4/2007
From: Tampa, FL, USA
Status: online 		i did one big port to the rear too, seemed like it would do more good on the way out than in. degree my engine? that is way too advanced for me right now but i'm guessing you start at tdc or bdc and measure at what degree stuff happens in the crank and what not. i'll give it a shot, i'm game, i've got nothing to loose, its only metal right?

_____________________________

Hyper ST PRO - RB WS7III/RB S5 L2G, JR, DX3R
Cen Matrix PBS - RB S3II/STS D21B (JBModz), Ace

(in reply to duckedup)
       Post #: 185

RE: Doubled my fuel economy! - 10/5/2007 2:18:00 PM   
lsurber


 

Posts: 251
Joined: 6/22/2007
From: Fort Worth, TX, USA
Status: offline 		Get yourself a degree wheel, fix it to the flywheel, make a pen mark on flywheel at TDC=0, then turn crank till crank induction port just starts to open. Record your results and repeat for crank induction close point. Do the same for the SPI timing. You don't really have to worry about the exhaust or intake port timings.

(in reply to j_blaze)
       Post #: 186

RE: Doubled my fuel economy! - 10/5/2007 2:31:24 PM   
lsurber


 

Posts: 251
Joined: 6/22/2007
From: Fort Worth, TX, USA
Status: offline 		Here is a degree wheel from another thread! I don't like it because I prefer measuring everything from TDC=0,360 but this will work fine. It just takes patients and being very careful. It is common to see measurements like ATDC, BTDC, BBDC, ABDC where A=after and B=before. I don't like this method because it cannot be used in a database to perform calculations without interpretation of the numbers.

Another solution would be to get a school protractor and drill the hole to fit the output shaft.

Attachments
Click to see fullsize image.
Click for fullsize


< Message edited by lsurber -- 10/5/2007 3:03:41 PM >

(in reply to j_blaze)
       Post #: 187

RE: Doubled my fuel economy! - 10/6/2007 1:09:46 AM   
tonyedge540


 

Posts: 14
Joined: 12/3/2004
From: toronto, ON, CANADA
Status: offline 		retarding the timing does increase fuel economy but you lose performance even if you mod it to compensate you still won't have the performance before you moded the engine i mod engines to and you need to increase air volume and fuel to get power it just how 2 stroke works if it was a 4 cycle than you can do more because it burns cleaner

(in reply to lsurber)
       Post #: 188

RE: Doubled my fuel economy! - 10/6/2007 4:07:08 AM   
lsurber


 

Posts: 251
Joined: 6/22/2007
From: Fort Worth, TX, USA
Status: offline 		I have more need for fuel economy than for power! I have other mods for power that almost throw the tires off the rims....!!!!! This mod has proven mileage benefits but a few timing issues which I will have worked out by late next week. I have one good engine for which I have posted complete timing profile on preceeding pages. This engine has performed very well with minimal power hits, excellent mileage, and extremely good thermal stability(no lean-out stalling under severely sustained high speed runs).

(in reply to tonyedge540)
       Post #: 189

RE: Doubled my fuel economy! - 11/3/2007 7:56:27 PM   
j_blaze



Posts: 1424
Joined: 1/4/2007
From: Tampa, FL, USA
Status: online 		i had the toki 21 spi out today and it ran great, temps were high but a bit of richening got them down. its cooled down last couple weeks down here in fl, still crazy quick. it ran great on grass and gravel and the quiting went away, thats with a HUGE spi port too. the crazy low idle seems to be gone too. its more of a slow decrease of rpm's, 20 seconds or so, then it quits. kinda like a normal engine. i'll have it on the track tomorrow to see how the jumping affects the quiting. i ran this fuel tube configuration about 1 gallon with another engine and had no quits. we'll see. power is still there but topend seems to be slightly reduced. my truggy runs a bit faster on a long straight right now. with a modded non-spi 27 on it.

< Message edited by j_blaze -- 11/4/2007 1:22:19 AM >

_____________________________

Hyper ST PRO - RB WS7III/RB S5 L2G, JR, DX3R
Cen Matrix PBS - RB S3II/STS D21B (JBModz), Ace

(in reply to lsurber)