2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Diesel trick??

Thread Tools
 
Search this Thread
 
Old Sep 14, 2007 | 12:11 PM
  #1  
Rednation's Avatar
Thread Starter
Junior Member
 
Joined: Mar 2007
Posts: 41
Likes: 0
From: Minnesota
Diesel trick??

I have heard putting in a gallon of diesel into your tank when you fill up will help with lubrication in the rotors is this true or just BS.
Reply
Old Sep 14, 2007 | 12:19 PM
  #2  
farberio's Avatar
NASA-MW ST4
Tenured Member: 20 Years
iTrader: (7)
 
Joined: Dec 2004
Posts: 3,800
Likes: 3
From: Norcal, Bay Area
Sounds like you heard someone who has heard of premixing but doesn't know **** about it.

Search for 'premix' to get some answers.
Reply
Old Sep 14, 2007 | 12:27 PM
  #3  
Polishammer's Avatar
Full Member
 
Joined: Jul 2007
Posts: 55
Likes: 0
From: Dacula, GA
With the old diesel, might be, although I have never heard that. New diesel for sure not, as guess what, new diesel have lost a lot of its lubricacy (sulfur) and we are also adding 2-stroke oil
Reply
Old Sep 14, 2007 | 05:36 PM
  #4  
RX7Tuner.'s Avatar
I really Schruted it
Tenured Member 05 Years
 
Joined: Sep 2006
Posts: 573
Likes: 0
From: Grand Rapids, MI
Yes, infact your car will run on pure diesel. It has a similar engine as the Kompressor engine found in the more expensive mercedes. If you have a turbo model, you can use old grease from a deep fryer. It helps raise the compression for better combustion. Now if you really want some power...use 87 octane.

Brian
Reply
Old Sep 14, 2007 | 11:03 PM
  #5  
NCross's Avatar
I have a rotary addiction
Tenured Member: 15 Years
iTrader: (18)
 
Joined: Jun 2006
Posts: 4,815
Likes: 24
From: Columbia, Tennessee
diesel in a gasoline engine would create compression problems and just wouldn't start... Enough diesel would actually blow it pretty good.
Reply
Old Sep 14, 2007 | 11:24 PM
  #6  
toplessFC3Sman's Avatar
Rotary Freak
iTrader: (1)
 
Joined: May 2006
Posts: 2,169
Likes: 5
From: Ann Arbor, MI
diesel has a much lower equivalent octane rating than gasoline, so you would have significantly less knock protection if you were able to start the car in the first place. If you did manage to coax it to life and keep it running, dont put much load on it or it will knock/detonate/whatever you want to call it, and then bye bye apex seals.
Reply
Old Sep 15, 2007 | 07:30 AM
  #7  
slow_2ed_gen's Avatar
Senior Member
Tenured Member 05 Years
 
Joined: Jun 2005
Posts: 624
Likes: 1
From: fort myers beach, FL
i'm pretty sure diesel is like 48 octane...
Reply
Old Sep 15, 2007 | 07:43 AM
  #8  
Pele's Avatar
Right near Malloy
Tenured Member: 25 Years
Liked
Loved
Community Favorite
iTrader: (28)
 
Joined: Dec 1999
Posts: 7,855
Likes: 517
From: Behind a workbench, repairing FC Electronics.
Diesel does not have octane.
Diesel has a CETANE rating, which is the OPPOSITE of OCTANE. Cetane refers to the fuel's ability to ignite by compression. Not to resist it.
http://en.wikipedia.org/wiki/Cetane_number

Diesel in your engine won't ruin anything... It just plain won't run...

To ignite diesel, you need compression upwards of 17:1 with forced induction. 20:1 N/A... Anyone have these kinda numbers on a Rotary? Physically impossible due to the geometry of the rotors. 10:1 max. Any more and the dish of the rotor is so shallow that it actually splits the combustion chamber in two, one near the leading plug, one near the trailing.



Originally Posted by Polishammer
With the old diesel, might be, although I have never heard that. New diesel for sure not, as guess what, new diesel have lost a lot of its lubricacy (sulfur) and we are also adding 2-stroke oil
+1 to the only other useful post here.
Reply
Old Sep 15, 2007 | 09:03 AM
  #9  
toplessFC3Sman's Avatar
Rotary Freak
iTrader: (1)
 
Joined: May 2006
Posts: 2,169
Likes: 5
From: Ann Arbor, MI
no, diesel can be run at lower compression ratios than 17:1, it usually just requires a smaller pre-chamber to start in, and is not as efficient or powerful as your modern direct injection, high compression ratio turbodiesels. I know it's rating is a cetane rating, thus I said "equivalent octane", so we could *try* to compare apples to apples.

Basically, diesel is made to be easy to initially ignite because it needs to combust solely because of compression (thus being a compression ignition, aka CI, engine), whereas gasoline is made to be more difficult so that it takes the spark to do it. I really doubt you could get the engine to start in the first place, and definately not cold, but maybe if it were really nice and toasty from a nice hard run, and you started the car just from the gas left in the fuel rail and lines, until the diesel began to be drawn in, at which point the engine is pretty hot, you may get it to ignite for a few cycles before it dies or you damage something.
Reply
Old Sep 15, 2007 | 09:48 AM
  #10  
CrackHeadMel's Avatar
Learned alot | Alot to go
Tenured Member 20 Years
iTrader: (2)
 
Joined: Apr 2002
Posts: 4,232
Likes: 0
From: Rotaryland, New Hampshire
i was recently schooled in a diesel conversation, so will pass this along

diesel if run in a typical car berated or fuel injected manner would require aprox a 7:1 comp ratio, the diff being a diesel engine compresses just the air, and then the fuel is injected and combusts almost immediatly, and gasolien engines compress both the fuel and air

some good information is mixed in this thread

https://www.rx7club.com/auxiliary-injection-173/deisel-injection-648515/

-Jacob
Reply
Old Sep 15, 2007 | 12:11 PM
  #11  
ericgrau's Avatar
Clean.
Tenured Member 10 Years
iTrader: (1)
 
Joined: Mar 2005
Posts: 2,521
Likes: 3
From: Huntington Beach, CA
Kiss your engine goodbye if you do this. No joke. Only way it might survive is if there's not too much diesel in there.

You can add TCW-13 2 stroke oil when you fillup your gas tank, no more than 1/2 oz. per gallon of gasoline. This will provide extra lubrication for a little less wear and a little better compression. Gas stations, walmart, etc., etc. carry it.
Reply
Old Sep 16, 2007 | 12:01 AM
  #12  
RX7Tuner.'s Avatar
I really Schruted it
Tenured Member 05 Years
 
Joined: Sep 2006
Posts: 573
Likes: 0
From: Grand Rapids, MI
I run 1oz per gallon. And you won't get any better compression.
Reply
Old Sep 16, 2007 | 11:48 AM
  #13  
ericgrau's Avatar
Clean.
Tenured Member 10 Years
iTrader: (1)
 
Joined: Mar 2005
Posts: 2,521
Likes: 3
From: Huntington Beach, CA
I didn't say the improvement would be noticeable. Maybe I should have said "tiny" instead of "little"? That's what I meant. But sealing is part of what the lubricant does. Heh, compared to zero lubrication I bet the improvement in compression would be noticeable. Plus if you keep wear down and keep the engine clean that'll help compression in the long run, no?
Reply
Old Sep 16, 2007 | 12:11 PM
  #14  
got_boost's Avatar
R.E Amemiya
Tenured Member: 20 Years
Liked
Loved
iTrader: (16)
 
Joined: Oct 2004
Posts: 1,266
Likes: 1
From: Montreal, Canada
Originally Posted by RX7Tuner.
Yes, infact your car will run on pure diesel. It has a similar engine as the Kompressor engine found in the more expensive mercedes. If you have a turbo model, you can use old grease from a deep fryer. It helps raise the compression for better combustion. Now if you really want some power...use 87 octane.

Brian
i dont remember where but i know i saw a tv show that actually tried those.
its either Mythbusters or Top Gear.
but they actually got a Volvo going with old fast food used oil.
and the car actually ran "great" !!!
Reply
Old Sep 16, 2007 | 01:08 PM
  #15  
RX7Tuner.'s Avatar
I really Schruted it
Tenured Member 05 Years
 
Joined: Sep 2006
Posts: 573
Likes: 0
From: Grand Rapids, MI
Originally Posted by ericgrau
I didn't say the improvement would be noticeable. Maybe I should have said "tiny" instead of "little"? That's what I meant. But sealing is part of what the lubricant does. Heh, compared to zero lubrication I bet the improvement in compression would be noticeable. Plus if you keep wear down and keep the engine clean that'll help compression in the long run, no?
Lubrication is important but you are getting it through the OMP. Adding two stroke oil to an engine with an OMP isn't going to add compression. If you have zero lubrication than your engine will not be running for long. I personally premix so I agree that it's better but if it's a stock engine, it's pointless.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
$lacker
3rd Generation Specific (1993-2002)
8
Feb 13, 2016 05:26 PM
TrboMike
NE RX-7 Forum
4
Sep 28, 2015 09:40 PM
Captain Hook
2nd Generation Specific (1986-1992)
8
Sep 22, 2015 01:12 PM
dradon03
Single Turbo RX-7's
8
Sep 18, 2015 05:57 AM
yetter227
2nd Generation Specific (1986-1992)
20
Sep 5, 2015 11:57 PM




All times are GMT -5. The time now is 03:09 AM.