A bit of advice on the boards but mainly a custom turbo.

rikymaru · Post by **rikymaru** » August 16th, 2002, 9:30 am

<BLOCKQUOTE>quote:<HR> you've got a ton of mis-information in that post. Im too tired to break it down, but here are some key points...1) Static compression has nothing to do with amount of air. Its simply volume at TDC over volume at BDC.2) If 87 Octane is 87% octane as you said, then whats your definition of 118 octane gas?3) the 400 whp Miata was on pump gas with 9.5:1 compression. I dont know where you get all this "only on race gas" stuff. Sorry if im fullfilling your story about nitpicking info, but last time i checked its better to provide CORRECT info. <HR></BLOCKQUOTE>Hehe. You know, I am an idiot. I should have been using <A HREF="http://www.howstuffworks.com" TARGET=_blank>www.howstuffworks.com</A> the whole tie. Would have saved me a TON of trouble. I'll save people the trouble of scanning the pages. All of this will be copy and pasted straight from the site. <A HREF="http://www.howstuffworks.com/question642.htm" TARGET=_blank>http://www.howstuffworks.com/question642.htm</A> "If you want to make a high-power 4-stroke engine, there are a couple of different ways to accomplish your goal. One way is to increase the displacement. Another is to stuff more air into the engine with a turbocharger or a supercharger. If you want to go to extremes, you would replace gasoline altogether and use a more energetic fuel. Top fuel dragsters do all three. Since nitromethane is not as dense as gasoline in terms of energy, so you do not get an 8-time improvement in terms of power. It is more like a 2.5-time improvement (see this page for a comparison). *******Still, you can double or triple your engine's horsepower simply by changing the fuel. ****** (this is a key part)That's a huge improvement!" <A HREF="http://www.howstuffworks.com/question90.htm" TARGET=_blank>http://www.howstuffworks.com/question90.htm</A> "The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting. The compression ratio of your engine determines the octane rating of the gas you must use in the car. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more. The name "octane" comes from the following fact: When you take crude oil and "crack" it in a refinery, you end up getting hydrocarbon chains of different lengths. These different chain lengths can then be separated from each other and blended to form different fuels. For example, you may have heard of methane, propane and butane. All three of them are hydrocarbons. Methane has just a single carbon atom. Propane has three carbon atoms chained together. Butane has four carbon atoms chained together. Pentane has five, hexane has six, heptane has seven and octane has eight carbons chained together. (hehe...I was right. Apparently it is

turns out that heptane handles compression very poorly. Compress it just a little and it ignites spontaneously. Octane handles compression very well -- you can compress it a lot and nothing happens. (READ THIS PART PROTEGEGTS)**********Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). **********It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio. During WWI, it was discovered that you can add a chemical called tetraethyl lead to gasoline and significantly improve its octane rating. Cheaper grades of gasoline could be made usable by adding this chemical. This led to the widespread use of "ethyl" or "leaded" gasoline. When lead was banned, gasoline got more expensive because refineries could not boost the octane ratings of cheaper grades any more. Airplanes are still allowed to use leaded gasoline, and octane ratings of 115 are commonly used in super-high-performance piston airplane engines (jet engines burn kerosene, by the way)."Oh, and it is TETRAETHYL. Guess I messed that up. And Protege, your right that it doesn't make sense about 87/13 percent of the gasoline. I guess I didn't explain it that well. I'll give it a try. The rating is an iso-octane volume in a fuel consisting the mixture of iso-octane and normal heptane. It's not the volume of gas but the volmue of octane to heptane IN the gas. So 118 octane isn;t going to be 118% octane....it just means there is now a lack of heptane and an extra 18% of the volume of gas which would otherwise be other chemicals is now octane.Oh..and I found this. <A HREF="http://www.ibmwr.org/otech/octane.html" TARGET=_blank>http://www.ibmwr.org/otech/octane.html</A> Best damned one of the bunch. It explains ROM and MON. I honestly didn't remember the formula so I wasn't going to mention them.Your a big fan of this Miata guy. Tell me, is he running on Forged pistons? If so then he has changed his top end and made it stronger to handle the extra stress. A popular DSM upgrade is to switch from 7.5:1 pistons into a forged set of 8.5:1 or even 9.1:1. In that case the top end has been changed and the engine is now stronger. Where do I get this "race gas" stuff from? I learned it from all the above. Yea, it is called race gas becasue when you "race" the "gas that is made for race" makes you faster. About 2.5 times actually, according to an accredited source I put above.For The mod: <A HREF="http://www.howstuffworks.com/engine5.htm" TARGET=_blank>http://www.howstuffworks.com/engine5.htm</A> Increase the compression ratio - Higher compression ratios produce more power, up to a point. The more you compress the air/fuel mixture, however, the more likely it is to spontaneously burst into flame (before the spark plug ignites it). Higher-octane gasolines prevent this sort of early combustion. That is why high-performance cars generally need high-octane gasoline -- their engines are using higher compression ratios to get more power. In no way was I saying you could not turbocharge a high compression car. Hell, the Dodge Viper gets a TT system and it has 9.5:1. Thene again, I've heard some bad things about Hennessy (there is a site devoted to hating him) But in relation to the COMPRESSION cycle the more PSI (pounds per square inch) of air that you are forcing into the engine the more it has to compress. You can balance that out with a good air/fuel ratio and probably make a good amount of boost. But that good ratio and 93 octane can only take you so far until the initial spark will blow your engine. That's what stops Supra owners from running 10000 PSI. Or a car from having a 15.5:1 compression ratio. There has to come to the point when there is too much power. And again, the 420HP Miata (it was a purple one) that I saw on Sports Compact Car in the August issue of last year ran 320HP daily driven but at the track could become a 420 HP by upping his boost on race additives and a higher octane.Yea, I like providing the right information. It works better that way.

rikymaru · Post by **rikymaru** » August 16th, 2002, 9:41 am

Oh, and BTW David I read that post in the probetalk. Good stuff man. But, as you yourself said, the higher compression lower psi boost engine will be better under race conditions than the low compression high boost. I can't agree more. But the low compression engine will have less daily stress/get better gas mileage. I'm an 18 year old student in college. I, and most people, can't afford to tune a high compression engine just right so it can use high boost. The risk of detonation is too great. So you have to ask yourself which are you willing to lose the most: your form of superinduction (turbo or super) for going over it's bounds or your engine? I can lsoe my turbo...I'd still be able to get to school. I cannot afford to lose an engine though.9:2.1 CR + 12psi = 16.7 DynamicCR 8:1.1 CR + 15.7psi = 16.7 DynamicCRI like that comparison from the probetalk. I'd take the lower compression becasue you have more room to work with. The higher compression could be tuned better for racing on the street/drag but on the safe side the 8:1.1 would be enough for me. I guess it all comes down to personal preference.

David Coleman · Post by **David Coleman** » August 16th, 2002, 10:14 am

Ric's miata was on pump gas. That's 93 octane. Not race gas. He's on this board, so you can ask him if you wish...Higher compression gets better gas milage than lower compression. It's thermal effeciency, plain and simple. It's really a sweet deal, because you make more power and get better gas milage. Higher compression engines will also spool faster [all other variables equal] than its lower compression counterpart.Note how even the DSM guys switch to 2G 8.5:1 pistons or aftermarket 9:1 pistons. That's because off boost, the engine is a dog, a low compression slug. Relying on your turbo to make all your power on a street driven car will not make for much fun unless you like to be at high engine loads frequently [to make boost].Yes, dropping compression and raising boost will net more power. But where? Just peak power is useless if there's no big flat torque curve for a daily driver. Your car weighs more than 2000#, so you can't really apply the engine applications from Drag hondas [the Nuformz Focus; 850hp, 450ft/lbs] or F1 cars [1200bhp, 600ft/lbs], as you need torque with your relatively heavy car. There's a MKIV out in Texas I believe, that has dropped his CR below 7:1, and runs 40psi+. Yeah, he runs 10's on stock turbos, but when he's putting 120whp down at peak off boost, that's probably not a fun 3400# car to drive on the street. Of course, he knows this, and it's a race only car. I'd be interested to see if it could even ignite 93 octane off boost with that CR.

maldo · Post by **maldo** » August 16th, 2002, 1:51 pm

Man you guys whine a lot!Why spit out regurgated info that we know. The fact is Ric was on a stock bottom end, period. No forged pistons, just good old 9.4:1CR with 401rwhp before the motor went. The trannies went before the motor, something like 5 of them until he swapped to an RX-7 tranny.No one is bashin DSM's, they are great cars with very potent motors. The guys who tune them just tend to like the lower compression with more boost which lends itself to poor off the line and off boost performance. The fact is the B6T runs quite poorly with the low compression. How do I know? I have one, do you? My muffler tip is covered in black soot from running so rich, Albi's motor is even worse for some reason. Are you trying to tell me that the B6T can handle 22 psi on stock internals? If you are, I find that quite funny at the stock head gasket has problems over 18psi. Sure the internals can handle a fair load but the guys running 18+psi use forged pistons that have the 9.5:1CR. The higher CR works on these motors. If it didn't how do you explain the fact that Flyin Miata is able to have sold over 1000 kits for the standard miata without any problems? I discussed the CR issue with Bill Cardell in length one day because I had been looking at going with the 8.8:1CR pistons from the auto miata. No need he said, his customers are able to run advanced ignition, proper tuning of course, and 12psi all day at that ratio. You say that 18psi on a daily driver won't hold on a MX-3. I see it as quite possible with the proper tuning. From what I remember is that Ric had been using his Miata for some time as a daily driver - different motor you say? Nope, everything is the same. The gtx guys have been using miata motors for some time.

ProtegeSTS · Post by **ProtegeSTS** » August 16th, 2002, 2:30 pm

<BLOCKQUOTE>quote:<HR>Originally posted by maldo: Man you guys whine a lot!Why spit out regurgated info that we know. The fact is Ric was on a stock bottom end, period. No forged pistons, just good old 9.4:1CR with 401rwhp before the motor went. The trannies went before the motor, something like 5 of them until he swapped to an RX-7 tranny.No one is bashin DSM's, they are great cars with very potent motors. The guys who tune them just tend to like the lower compression with more boost which lends itself to poor off the line and off boost performance. The fact is the B6T runs quite poorly with the low compression. How do I know? I have one, do you? My muffler tip is covered in black soot from running so rich, Albi's motor is even worse for some reason. Are you trying to tell me that the B6T can handle 22 psi on stock internals? If you are, I find that quite funny at the stock head gasket has problems over 18psi. Sure the internals can handle a fair load but the guys running 18+psi use forged pistons that have the 9.5:1CR. The higher CR works on these motors. If it didn't how do you explain the fact that Flyin Miata is able to have sold over 1000 kits for the standard miata without any problems? I discussed the CR issue with Bill Cardell in length one day because I had been looking at going with the 8.8:1CR pistons from the auto miata. No need he said, his customers are able to run advanced ignition, proper tuning of course, and 12psi all day at that ratio. You say that 18psi on a daily driver won't hold on a MX-3. I see it as quite possible with the proper tuning. From what I remember is that Ric had been using his Miata for some time as a daily driver - different motor you say? Nope, everything is the same. The gtx guys have been using miata motors for some time.<HR></BLOCKQUOTE> Chris...the Miata BP motors were 9.5:1, not 9.4:1

Only the B6 ones were 9.4:1.

I_love_my_MX-3 · Post by **I_love_my_MX-3** » August 16th, 2002, 4:15 pm

rikymaru whats your E-mail I wanted to ask you about theat fuel pump.

maldo · Post by **maldo** » August 16th, 2002, 4:15 pm

My bad... [img]shrug.gif"%20border="0[/img]

Swego · Post by **Swego** » August 16th, 2002, 9:21 pm

YEp email me, I'm interested in your fuel pump also.

FinaJet07 · Post by **FinaJet07** » August 22nd, 2002, 1:53 am

why did my last post get deleted? i guess the mods dont like to here the other side to things.

voltaire · Post by **voltaire** » August 22nd, 2002, 2:25 am

Whoa, that weird link is out there! You're right, that's a whole lot of non-info. How did you stumble on that?!?I think I'm gonna steal a part of it:"YOU are the lowest form. YOU can't procreate alone. YOU destroyed the village. YOU destroyed the family. YOU destroyed childhood. YOU destroyed naturalism. YOU don't know the Truth. YOU pitiful mindless fools, YOU are educated stupid. YOU worship cubeless word. YOU are your own poison. YOU create your own hell. YOU must seek Time Cube. ************************************* 1 day god vs 4 day Genius. I know 4 different Worlds, the ingredients existed, but I created a 4-World recipe. 1 god day belief is stupidity. I am the wisest human and offer $1,000.00 to the 1st to disprove my wisdom claim above the educated stupid. I lectured/debated at MIT & have 2 hour video proof. You are but mindless asses."

mx3gsr · Post by **mx3gsr** » August 22nd, 2002, 2:37 am

<BLOCKQUOTE>quote:<HR>Originally posted by rikymaru: Before I go on I'm sensing the anti-DSM sentiment here. I really hate to be all prideful about cars but, for the bang for your buck, you cannot beat a DSM. The aftermarket is cheap and the engines are more than reliable. The only problem is the AWD trannies. But ALL awd trannies suck. <HR></BLOCKQUOTE>Just thought I'd drag this even further off topic.I do agree the DSM list is full of fantastic helpful people, and some great mechanics. It's also got almost 4000 members and a much larger following.Having said that, DSM cars have some of the most unreliable engines out there, especially the 2nd gen 4G63. Ask around the DSM circles, those guys go through engines and transmissions like they were disposeable diapers. The AWD trannies grind the 1-2 shift almost from the factory, and anyone with even only BPU addons has likely gone through more than a few transmission changes. Timing belt and crankwalk problems are notorious, both leading to unrepairable engine failure. It is so bad they should have been recalled (an hidden bulletins show Mitsubishi to have been well aware of the problems). No joke, I get 15+ calls EVERY DAY from 2nd gen eclipse/talon owners asking if we carry engines for their cars because theirs failed 20 minutes outside of warranty.1st gen cars are ugly as sin, and the 2nd gen cars are slick looking but riddled with fit & finish problems and electrical issues, not to mention that lovely crankwalk. The resale value is horrendous because they're all beaten to death and people know the maintenance record on those cars is right up there with the Pontiac Fiero.Comparing performance numbers from a high (over) priced sports car like the talon/eclipse with a little econo-sport coupe like the MX-3 is silly.But to each his own, whatever turns your crank (shaft).

VizualXTC · Post by **VizualXTC** » August 22nd, 2002, 3:14 am

<BLOCKQUOTE>quote:<HR>Originally posted by mx3gsr: Just thought I'd drag this even further off topic.I do agree the DSM list is full of fantastic helpful people, and some great mechanics. It's also got almost 4000 members and a much larger following.Having said that, DSM cars have some of the most unreliable engines out there, especially the 2nd gen 4G63. Ask around the DSM circles, those guys go through engines and transmissions like they were disposeable diapers. The AWD trannies grind the 1-2 shift almost from the factory, and anyone with even only BPU addons has likely gone through more than a few transmission changes. Timing belt and crankwalk problems are notorious, both leading to unrepairable engine failure. It is so bad they should have been recalled (an hidden bulletins show Mitsubishi to have been well aware of the problems). No joke, I get 15+ calls EVERY DAY from 2nd gen eclipse/talon owners asking if we carry engines for their cars because theirs failed 20 minutes outside of warranty.1st gen cars are ugly as sin, and the 2nd gen cars are slick looking but riddled with fit & finish problems and electrical issues, not to mention that lovely crankwalk. The resale value is horrendous because they're all beaten to death and people know the maintenance record on those cars is right up there with the Pontiac Fiero.Comparing performance numbers from a high (over) priced sports car like the talon/eclipse with a little econo-sport coupe like the MX-3 is silly.But to each his own, whatever turns your crank (shaft).<HR></BLOCKQUOTE>OUCH, Sean! stick it to him man. j/k I have heard MANY horror stories about the maintainance issues of the 2nd gen eclipse. My cousin used to own one and it was in the shop at least once a paycheck. Even my ex friend with a honda civic has been to the shop much more often than I and my baby have. Oh well, live and learn.

MX3RS · Post by **MX3RS** » August 22nd, 2002, 3:37 am

You guys wanna hear something more about compression? My car (88 Mitsu Starion Turbo) has a factory 7:1 comp ratio. Now that is LOW. Granted I run around daily with 15-18psi on 91oct fuel without even the slightest hint of detonation and I am still running quite rich. Because of the low compression some people are running well over 20psi on the stock cast pistons, although I wouldn't do it.

MX-3.com

A bit of advice on the boards but mainly a custom turbo.

Re: A bit of advice on the boards but mainly a custom turbo.

Re: A bit of advice on the boards but mainly a custom turbo.

Re: A bit of advice on the boards but mainly a custom turbo.

Re: A bit of advice on the boards but mainly a custom turbo.

Re: A bit of advice on the boards but mainly a custom turbo.

Re: A bit of advice on the boards but mainly a custom turbo.

Re: A bit of advice on the boards but mainly a custom turbo.

Re: A bit of advice on the boards but mainly a custom turbo.

Re: A bit of advice on the boards but mainly a custom turbo.

Re: A bit of advice on the boards but mainly a custom turbo.

Re: A bit of advice on the boards but mainly a custom turbo.

Re: A bit of advice on the boards but mainly a custom turbo.

Re: A bit of advice on the boards but mainly a custom turbo.