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Old 02-08-2009, 03:18 PM   #61
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Given the same two compounds and total contact patch area, a wider tire is slightly better. +1 to DeerHunter's comments.

I also like how everyone calls a pushrod V8 a OHV engine. All automotive engines since the 60's are OHV.
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Old 02-08-2009, 03:47 PM   #62
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Originally Posted by patsmx5 View Post
I also like how everyone calls a pushrod V8 a OHV engine. All automotive engines since the 60's are OHV.
Technically, you're right. However, OHV is the commonly accepted term for a push-rod design.
http://en.wikipedia.org/wiki/Pushrod
OHV, OHC, SOHC and DOHC (twin cam) engine - Automotive illustrated glossary
NationMaster - Encyclopedia: OHV
Etc, etc.
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Old 02-08-2009, 04:02 PM   #63
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I like pancakes.

I also like LS engines. Which reminds me, my cousin has a NASTY WS6 Trans Am with a twin turbo setup... I still gotta hit him up for a ride in it. I think he said at low boost (6 or 7psi if I recall) its making in the upper 600's at the wheels. If he had any sense though, he would have gone with a BMW V8 swap...

He also said he has another engine he is building up, and he will be going for 900, and hopes to see 1000 if hese lucky. I cant imagine that kind of fun on the streets.
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Old 02-08-2009, 08:22 PM   #64
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Originally Posted by DeerHunter View Post
Look at a top fuel dragster. It's rear tires are not exceptionally wide compared to the power it has to put down (certainly not 12 times wider than a Z06, for instance). It gets traction from a VERY sticky compound and low tire pressures (which gives a bigger footprint). Also consider that as it accelerates, the tire grows due to centripetal force, which has the effect of changing the shape of the contact patch (becomes less wide) without changing the total size (which depends on vehicle weight and tire pressure). Even as the shape of the contact patch changes, traction doesn't alter appreciably (discounting the effect of weight transfer on vehicle weight per corner).
You forget two of the primary reasons dragster's tires are configured the way they are. First, to allow the tire to flex, reducing torque feedback into the drivetrain as a preventative measure to reduce the chance of rupturing the pumpkin. Second, as the tires expand, it changes the effective gear ratio, aiding in accelleration.

- L
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Old 02-08-2009, 08:28 PM   #65
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Quote:
Originally Posted by mazda/nissan View Post
prove it
Okay:

BME Top Fuel Dragster Specifications



Whats that I see there? Could that be, TWO valves per cylinder????

500 Cubic Inch V8, Hemi-spherical combustion chambers
[email protected]
That comes out to 987.65432098765432098765432098765hp/liter inch from an 8.1 liter engine, or 16hp per cubic inch.



I'd bet you those two valves would flow more air than three or four miata motors put together.
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Old 02-08-2009, 09:12 PM   #66
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Type: Tipo 055
Year: 2005
Number of cylinders: 10
Configuration: 90 vee, 40 valves
Capacity: 2997
RPM: 19000
Power: 940 bhp

hm.. 940HP from a 3 liter naturally aspirated motor doesn't sound bad for only having 2 extra valves per cylinder
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Old 02-08-2009, 09:43 PM   #67
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Quote:
Originally Posted by patsmx5 View Post
All automotive engines since the 60's are OHV.
My RX7 begs your apology, sir.

Quote:
Originally Posted by elesjuan View Post
Whats that I see there? Could that be, TWO valves per cylinder????
500 Cubic Inch V8, Hemi-spherical combustion chambers
[email protected]
That comes out to 987.65432098765432098765432098765hp/liter inch from an 8.1 liter engine, or 16hp per cubic inch.

I'd bet you those two valves would flow more air than three or four miata motors put together.
Top Fuel...Top Fuel...Top Fuel...
What kind of fuel do they use in Top Fuel? Is it gasoline? I don't think it is. I believe it is much more powerful than gasoline. And that the engines have seriously overdriven blowers on them. And most importantly that they are limited to two valves per cylinder by the rules or they would do otherwise.
But I'll have to check with Mr. Don Garlits in the morning.
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Old 02-08-2009, 09:47 PM   #68
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Deerhunter - while I hope to not come across as knocking on your setup, I strongly dissagree with your choice of tire/wheel. You've got one sick car there from what I see in your sig so please don't get me wrong - I've got a lot of respect for what you've got going on there, but that's a perfect example of what I was referring to... although granted we all have our own goals for our cars and want different things and if what you've got makes you happy, you've done it right.
One big big issue that makes me say that you have far too little rubber is a concept that is given far more importance in the world of motorcycles (at least sport bikes). More capability to get up to speed means needing more ability to control that speed - in the next corner coming up, in an event of something unexpected happening, etc. This is not a huge issue for most miata owners - a 205/50/15 of a decent sport tire can handle those situations you may get into when you only have enough acceleration to do something like an 18 second 1/4 mile. For my 929RR however, (or a 350 whp miata like yours or the ones I was referring to) it is essential to be able not only to have enough traction to accelerate but enough to control the car at the speeds you can attain so quickly.
Granted, if you want to baby it around all the time... its cool.
You're right, the tire compound is more important than width, but both are necessary parts to the equation of total grip, and I can use all of my 225/50/13 Goodyear Eagle road race slick (9 inch wide footprint) with a current 170ish whp.
All I'm saying is, sure a 205 tire can get a 400 hp miata from point a to point b, but to use it properly requires an a.) sticky tire that is b.) WIDE.

Honestly, how sad would it be to go on a group drive with a local maita club and out accelerate every other guy on each straight but then have to SLAM on the brakes for each oncoming corner because you can't take the turn any faster than the stock 1.6L behind you, but you have 30 mph more speed to scrub off than he does.
-Ryan
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Old 02-08-2009, 09:47 PM   #69
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The Most Powerful Diesel Engine in the World

The Wartsila-Sulzer RTA96-C turbocharged two-stroke diesel engine is the most powerful and most efficient prime-mover in the world today. The Aioi Works of Japan's Diesel United, Ltd built the first engines and is where some of these pictures were taken.

It is available in 6 through 14 cylinder versions, all are inline engines. These engines were designed primarily for very large container ships. Ship owners like a single engine/single propeller design and the new generation of larger container ships needed a bigger engine to propel them.

The cylinder bore is just under 38" and the stroke is just over 98". Each cylinder displaces 111,143 cubic inches (1820 liters) and produces 7780 horsepower. Total displacement comes out to 1,556,002 cubic inches (25,480 liters) for the fourteen cylinder version.
Some facts on the 14 cylinder version:
Total engine weight: 2300 tons (The crankshaft alone weighs 300 tons.)
Length: 89 feet
Height: 44 feet
Maximum power: 108,920 hp at 102 rpm
Maximum torque: 5,608,312 lb/ft at 102rpm

Fuel consumption at maximum power is 0.278 lbs per hp per hour (Brake Specific Fuel Consumption). Fuel consumption at maximum economy is 0.260 lbs/hp/hour. At maximum economy the engine exceeds 50% thermal efficiency. That is, more than 50% of the energy in the fuel in converted to motion.
For comparison, most automotive and small aircraft engines have BSFC figures in the 0.40-0.60 lbs/hp/hr range and 25-30% thermal efficiency range.

Even at its most efficient power setting, the big 14 consumes 1,660 gallons of heavy fuel oil per hour.



Okay, put the dicks away.. Think that thing might have OHC anyway.
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Old 02-08-2009, 09:53 PM   #70
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Last I checked, that engine ^ or a top fuel engine cant be run in a normal street driven car... that being said, 4 valves per cylinder is still better than 2 IN AN ACTUAL CAR, not in a top fuel dragster or a million cubic inch diesel.
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Old 02-08-2009, 10:25 PM   #71
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Quote:
Originally Posted by ThePass View Post
Deerhunter - while I hope to not come across as knocking on your setup, I strongly dissagree with your choice of tire/wheel.
...
Honestly, how sad would it be to go on a group drive with a local maita club and out accelerate every other guy on each straight but then have to SLAM on the brakes for each oncoming corner because you can't take the turn any faster than the stock 1.6L behind you, but you have 30 mph more speed to scrub off than he does.
-Ryan
Ryan, thanks for putting your comments so tactfully. I put a lot of thought into keeping the handling and braking capabilities commensurate with my available power. Balance in any car is critical - especially when driving quickly on unknown back roads, when anything can be waiting for you around a blind corner. At the same time as I did the engine, I changed to an NB front subframe/steering rack (for improved geometry), put in FM's AFCO suspension (which has a ton a usable travel for real-world roads) and had the car aligned and corner weighted. I already had the Wilwood BBK from Goodwin for more consistent whoa. Part of the reason I have the tire size I have is that I stayed with the BBS alloys (15 inchers cribbed from a '95M) to keep the look of my L.E. intact.

What you're saying is completely true - a wider tire on a wider wheel will handle better. Why am I not worried (and it's not because I baby it): First, the weight of my car has not altered appreciably and it was quite capable of scaring the bejeezus out of a passenger on any back road - with only 200 rwhp and 195 section T1-Rs; Second, a narrower tire is in effect a "safety valve". If my cornering speeds are limited, I won't corner as hard, which makes the unknown around the blind turn easier to deal with. After all, it's not a time trial, driving near the limit is where the fun is. If the limit goes up 20%, the fun doesn't necessarily increase but the danger factor most certainly does. In any case, I've never had problems keeping up with anybody on any group drive before and I don't expect to in the future.

I autocross and attend HPDEs many times a year and have a separate set of wheels with RA-1s mounted for when time IS critical. When I can afford it, I'll buy a set of 15x8 or 9" 6ULs and run Hoosiers on the track.

I haven't yet had the opportunity to go back road burning yet (winter intervened), but I'm heading to Texas for Miata World II and plan to take the long way there. Perhaps I'll change my mind about tire sizes during that trip - we'll see.

- Steven
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Old 02-08-2009, 10:31 PM   #72
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Quote:
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So why do they run a supercharger instead of a turbo? Same reason they run 2 valve heads.
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Old 02-08-2009, 10:41 PM   #73
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Quote:
Originally Posted by DeerHunter View Post
a narrower tire is in effect a "safety valve". If my cornering speeds are limited, I won't corner as hard, which makes the unknown around the blind turn easier to deal with. After all, it's not a time trial, driving near the limit is where the fun is. If the limit goes up 20%, the fun doesn't necessarily increase but the danger factor most certainly does.
- Steven
Very well put, and a good argument for (relatively) mild tires (both in width and compound) for the street. I'm glad to see you've thought it out and are very satisfied with the choice.
Still, I want to see one of these monsters built for some real vette-spanking track duty. I miss FM's Track Dog - 350 hp/tq widebody. Last that thing was out on the track was 03' I think.
-Ryan
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Old 02-08-2009, 11:46 PM   #74
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Originally Posted by patsmx5 View Post
So why do they run a supercharger instead of a turbo? Same reason they run 2 valve heads.
+1
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Old 02-08-2009, 11:55 PM   #75
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I saw Track Dog tucked into a corner at FM's new facility. It was covered with dust and quite forlorn. Bill wasn't sure what the plans are for the car, but I hope that it takes to the track again in one form or another. If they stuffed a tuned LSx into it, it will probably be unbeatable.

The problem I forsee, if I start doing hard core track events is two-fold, safety and cooling. My car is first and foremost a street vehicle, so I don't want to add a roll bar (never mind a cage), race seat, harnesses, etc. I also don't want to add an extraction hood (I'm going for a stealth look). I'll have to settle for spanking such cars in other environments
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Old 02-09-2009, 12:51 AM   #76
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Originally Posted by DeerHunter View Post
Perhaps it has and I'm certainly open to new data if it's presented in a compelling way. I don't think, however, that comparing a space saver to a regular tire holds water. A space saver is generally made from a very durable (read: hard) compound and runs very high tire pressures (60 psi or so) so that it doesn't disintegrate when used. If the pressures are equalized, as you suggest,
I suggested running the same pressure, then lowering it onto a clean sheet of paper. This will show the footprint.
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Old 02-09-2009, 02:04 AM   #77
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Originally Posted by JasonC SBB View Post
I suggested running the same pressure, then lowering it onto a clean sheet of paper. This will show the footprint.
Apologies - I misunderstood. Rather than using an extreme example like this, wouldn't it be more useful to compare, say, a 195 section width tire to a 235, using the same "paper" protocol? I'd be interested in the results of the space saver as well, but would put more stock in real-world size examples.
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Old 02-09-2009, 02:25 AM   #78
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Last I checked, that engine ^ or a top fuel engine cant be run in a normal street driven car... that being said, 4 valves per cylinder is still better than 2 IN AN ACTUAL CAR, not in a top fuel dragster or a million cubic inch diesel.
So riddle me this...

Why did it take 5.4 liters and a HUGE HUGE intake manifold to get 385bhp in the Cobra-R when GM broke 405bhp with 5.6 liters in a standard package?

Why did it take them 4.6 liters, 4 valves, and an eaton supercharger to get 400bhp in the 03/04? They seem to think the mod 'cammer is like gods grace on earth yet I haven't seen anything even remarkable come about it. Don't get me wrong, I've seen some crazy and supercool supra owning dynoqueen **** with the 03/04 Cobras....

I'll be honest, 95% of these discussions that I get involved in are for nothing more than amusement of the argument. Flat out, I like to debate and believe little of what I actually try and make points about on this or any other forum for that matter. Add ontop of that, I really enjoy getting the rise out of people.

Quite frankly If you don't like the LSx series engine because it only has 1 camshaft and is the same basic type of engine as the Gen I sbc of the 50s, fine. Thats your opinion and you're more than entitled to it. Fact of the matter is, I believe the reason GM still uses a singular camshaft and 2 valves / cylinder is because they can, and because it ******* works. Not only does it ******* work, it ******* works WELL. My grandfather used to say, "if its not broke, don't ******* break it just so you can fail at fixing it." Ever take notice of how many other motors GM use OHC on? Most of them, just not the only motor that matters to me.
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Old 02-09-2009, 03:04 AM   #79
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Originally Posted by Saml01 View Post
Someone figure out how to get an LS1 swapped OBD2 car to pass emissions damnit.
id assume you just use a later year motor it wouldnt be hard. plus the whole ecu is self contained and you can run wires to hook up the obd port.
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Old 02-09-2009, 03:09 AM   #80
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Quote:
Originally Posted by elesjuan View Post
So riddle me this...

Why did it take 5.4 liters and a HUGE HUGE intake manifold to get 385bhp in the Cobra-R when GM broke 405bhp with 5.6 liters in a standard package?

Why did it take them 4.6 liters, 4 valves, and an eaton supercharger to get 400bhp in the 03/04? They seem to think the mod 'cammer is like gods grace on earth yet I haven't seen anything even remarkable come about it. Don't get me wrong, I've seen some crazy and supercool supra owning dynoqueen **** with the 03/04 Cobras....

I'll be honest, 95% of these discussions that I get involved in are for nothing more than amusement of the argument. Flat out, I like to debate and believe little of what I actually try and make points about on this or any other forum for that matter. Add ontop of that, I really enjoy getting the rise out of people.

Quite frankly If you don't like the LSx series engine because it only has 1 camshaft and is the same basic type of engine as the Gen I sbc of the 50s, fine. Thats your opinion and you're more than entitled to it. Fact of the matter is, I believe the reason GM still uses a singular camshaft and 2 valves / cylinder is because they can, and because it ******* works. Not only does it ******* work, it ******* works WELL. My grandfather used to say, "if its not broke, don't ******* break it just so you can fail at fixing it." Ever take notice of how many other motors GM use OHC on? Most of them, just not the only motor that matters to me.
See, now your not so wrong...
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