Driving at high RPMs - Question

[lemosley01]

Yeah - LEEEEERRRROOOOYYYYY.

CobraRed01, lets be totally honest: How many cars in STOCK form are up to open track duty? Very few, and probably none in the price range of the Cobra. It has some weaknesses that can be cured, but makes a decent platform for OT once those weaknesses are addressed.

Remember, this car, as most, are not designed with continuous high RPM, continuous high G (compared to the street) operation for long periods.

 

[CobraRed01]

CobraRed01, lets be totally honest: How many cars in STOCK form are up to open track duty? Very few, and probably none in the price range of the Cobra. It has some weaknesses that can be cured, but makes a decent platform for OT once those weaknesses are addressed.

Remember, this car, as most, are not designed with continuous high RPM, continuous high G (compared to the street) operation for long periods.

I hear you. Of course, no car in stock form is truly setup for the abuse we love to put them through. Modding to improve our rides is really the name of the game anyway. I'm ready to do all the upgrades to make my Cobra handle the way I want, but it seems some engine mods may not be enough for the 4.6 aluminum modular. Despite addressing the poor oiling problem guys are apparently lunching mod motors regardless. This sounds like a fundamental flaw in the motor pointed out by quadcammer which modifications don't seem to fix. Kind of confirms suspicions I started to have when Ford said 4V modular "pinging" and "piston skirt" slap is "normal" in the 01/WAP blocks. What's scary is I keeping hearing about mods spinning bearings during normal street use after about 20K miles. Ouch. Glad I have my extended warranty. Hate to put alot on money to upgrade my New Edger and lunch a motor after only a few OT sessions.

Everyone is really happy with the new motor in the GT500 and feels it will be strong enough for some insane HP figures. So Ford does listen (to the drag/street racers, right now) and will get it right eventually. This is a good thing. Maybe a new and better aluminum block N/A will evolve someday.

 

[01vert]

This is like when I was younger and a girl trying to learn a manual for the first time asked me why you can't just leave it in fifth and start in this gear and leave it there rather than shift through all the gears. Seemed a lot easier to her.
Later on she was told by her boyfriend to downshift through everygear when slowing down. Coming to a stop at a light truned into headjerk city. Bouncing your head off the headrest and dash as she would downshift 3 gears in a row quickly to stop. Only rode with her once.

 

[oz98snake]

LOL at this thread - Paul, if you get a buzz from it, go ahead and cruise at 4000 rpm - I can tell that it is a WHOLE lot kinder on your engine to do this than it is to drag race the thing a few times a month as there is very little load on the engine when cruising!
Even stop start city driving would be harder on your motor than cruising down the freeway at 4500 rpm - and there are plenty of Cobras that commute in traffic every day.

As for open tracking or racing the mod motor - it has picked up a very undeserved reputation. The reality is that there is nothing fundamentally wrong with our engines - a stock normally aspirated 4V will run all day every day on most race tracks with no problems. They do need a little work if you up the power and stick it in a race car, but what engine doesn't to take it racing! The 5.0 Cammer crate engine is essentially the same damn block and heads, and it works just fine hour after hour in Grand Am cup race cars, and the DOHC mod motor has been used in other forms of racing like ALMS protoype for years with no problems.

The "oiling" issues you read about are related to the stock oil return passages having a bottleneck which can cause the oil to build up up top, and of course get low in the pan, possibly causing starvation problems in long high G turns - there is a very easy and well documented fix for this when building up a race motor. There have also been a few cases of the stock oil pump drive gear failing, but again, there are alternatives available that you would want to put in a built motor. The only other significant problem with the mod motor is that the stock cooling system was less than ideal as it allowed the rear cylinders to get too hot in a racing situation - again, there is a well documented fix for this.

My old 98 open tracker is more or less stock except for intake and exhaust and has never been apart - and it has had the living daylights flogged out of it on the track for years as well as street miles - and it has never missed a beat - it runs as quiet as a new one after 60K miles. I just did some quick math, and figured out that my engine has run at least 90 hours flat out on the track over the last 3 years - that's nearly 3 Le Mans 24hr races! Scary when I think about it that way, but it is still as strong as ever!

 

[Quadcammer]

LOL at this thread - Paul, if you get a buzz from it, go ahead and cruise at 4000 rpm - I can tell that it is a WHOLE lot kinder on your engine to do this than it is to drag race the thing a few times a month as there is very little load on the engine when cruising!
Even stop start city driving would be harder on your motor than cruising down the freeway at 4500 rpm - and there are plenty of Cobras that commute in traffic every day.

As for open tracking or racing the mod motor - it has picked up a very undeserved reputation. The reality is that there is nothing fundamentally wrong with our engines - a stock normally aspirated 4V will run all day every day on most race tracks with no problems. They do need a little work if you up the power and stick it in a race car, but what engine doesn't to take it racing! The 5.0 Cammer crate engine is essentially the same damn block and heads, and it works just fine hour after hour in Grand Am cup race cars, and the DOHC mod motor has been used in other forms of racing like ALMS protoype for years with no problems.

The "oiling" issues you read about are related to the stock oil return passages having a bottleneck which can cause the oil to build up up top, and of course get low in the pan, possibly causing starvation problems in long high G turns - there is a very easy and well documented fix for this when building up a race motor. There have also been a few cases of the stock oil pump drive gear failing, but again, there are alternatives available that you would want to put in a built motor. The only other significant problem with the mod motor is that the stock cooling system was less than ideal as it allowed the rear cylinders to get too hot in a racing situation - again, there is a well documented fix for this.

My old 98 open tracker is more or less stock except for intake and exhaust and has never been apart - and it has had the living daylights flogged out of it on the track for years as well as street miles - and it has never missed a beat - it runs as quiet as a new one after 60K miles. I just did some quick math, and figured out that my engine has run at least 90 hours flat out on the track over the last 3 years - that's nearly 3 Le Mans 24hr races! Scary when I think about it that way, but it is still as strong as ever!

load or not, its causing additional stress on the valvetrain for no reason.

 

[tyronejenkinsII]

TyroneJenkinsII - please tell me you are not the same Tyrone Jenkins of World of Warcraft fame...

Tyrone JenkinsII not Leroy Jenkins......sorry

 

[SKMCOBRA]

You guys are brutal here on the "New Edge" forum....but funny! :burn:

 

[Taz]

You guys are brutal here on the "New Edge" forum....but funny! :burn:

Typical New Edge thread. Mostly fiction, but good entertainment value.

Grab the popcorn and enjoy the show.

op:

 

[lemosley01]

Typical New Edge thread. Mostly fiction, but good entertainment value.

Care to set everyone straight so we don't perpetuate any myths? If you have some information, please share it. That's what the interweb is for.

 

[paulk]

Alright... so reading all the posts, is it safe to say that half the Cobra owners out there drive their cars like pussies or am I missing something?

I will continue to drive at 4k RPM until the bitch redlines, atleast I'll get excitement out of it and won't get bored when driving!!! Weeeeeeeeeeee

But seriously, thanks for those who responded with educated answers.

 

[Kcobra99]

Accually, I have found that 5th gear is useless in these cars with stock gears. Last year I went on a road trip with a friend who owned a 67 Dodge Charger 383 4 speed. we travelled at 65mph, I had cruise control on in 5th below 2000rpm and when we filled up for gas at the same time I was the one that had worse fuel economy. (I had a 17mpg avg and the Charger had a 18mpg avg) Fuel economy is based off of engine load as much as rpm. Look at a dyno sheet from a N/A 4v, they make very little torque below 3000rpm, then spike up, level off just past 4000rpm and start to drop after 5000rpm. This is the range that these engines are at their most efficent or can do the most work. I've tested this out, and travelling on the same road at the same speed (75mph) in 4th(3000rpm) and 5th(2000rpm) with the cruise control on I got 27mpg in 4th and 22mpg in 5th.

If you don't believe me try it out. cruise in 5th at 2000rpm or below and note how far you have to push the gas pedal. Then downshift to 4th, maintain the same speed and try to keep the rpms steady as possible. You'll notice that you don't need to put your foot into it as much at higher rpms, and you're not lugging the engine as much.

I wouldn't advise driving at 5000rpm all the time; that's pretty extreme, but these motors need rpms to build torque. I usually drive between 3-4000rpm on the highway with the cruise control on and have been getting the best gas mileage yet. And the exhaust noise isn't bad, they mellow out when holding at a steady rpm, unless you have a loud exhaust to begin with.

 

[CobraRed01]

LOL at this thread - Paul, if you get a buzz from it, go ahead and cruise at 4000 rpm - I can tell that it is a WHOLE lot kinder on your engine to do this than it is to drag race the thing a few times a month as there is very little load on the engine when cruising!
Even stop start city driving would be harder on your motor than cruising down the freeway at 4500 rpm - and there are plenty of Cobras that commute in traffic every day.

As for open tracking or racing the mod motor - it has picked up a very undeserved reputation. The reality is that there is nothing fundamentally wrong with our engines - a stock normally aspirated 4V will run all day every day on most race tracks with no problems. They do need a little work if you up the power and stick it in a race car, but what engine doesn't to take it racing! The 5.0 Cammer crate engine is essentially the same damn block and heads, and it works just fine hour after hour in Grand Am cup race cars, and the DOHC mod motor has been used in other forms of racing like ALMS protoype for years with no problems.

The "oiling" issues you read about are related to the stock oil return passages having a bottleneck which can cause the oil to build up up top, and of course get low in the pan, possibly causing starvation problems in long high G turns - there is a very easy and well documented fix for this when building up a race motor. There have also been a few cases of the stock oil pump drive gear failing, but again, there are alternatives available that you would want to put in a built motor. The only other significant problem with the mod motor is that the stock cooling system was less than ideal as it allowed the rear cylinders to get too hot in a racing situation - again, there is a well documented fix for this.

My old 98 open tracker is more or less stock except for intake and exhaust and has never been apart - and it has had the living daylights flogged out of it on the track for years as well as street miles - and it has never missed a beat - it runs as quiet as a new one after 60K miles. I just did some quick math, and figured out that my engine has run at least 90 hours flat out on the track over the last 3 years - that's nearly 3 Le Mans 24hr races! Scary when I think about it that way, but it is still as strong as ever!

oz98snake
Here's a great thread on cornercarvers.com that seems to cover the Modular 4.6 issue in great detail.

http://corner-carvers.com/forums/showthread.php?t=5993&highlight=modular+engine+problems

Aptly entitled: "DOHC Cobra Motor #2 Dies @ Limerock"

Per quadcammer's recommendation, I did a little research. Very interesting. I think some get lucking running their Mods all day for along time and others just get nailed. Sounds like you've got a solid Mod. I'm certainly hoping my 01 motor is as stout as your 98!!! Your 98 is running a Teksid block right? Is that block any better than the later WAP for this kind of abuse? It is interesting to note on the cornercarvers.com thread how a lot of these dedicated racers/OTers are surprised when the Mod breaks...especially a second time. Hell, if a 351 can run all day why can't a more "advanced" motor. Those "in the know" who race alot seem to change back to iron. I'm surprised to hear the 351 iron block is actually lighter than the 4.6 DOHC aluminum block.

I guess if your gonna run it LOUD all day you better have the $$$ to replace it when it blows. Hear that, Paul? Weeeeeeeeeee$$$$$$$$$$$$$$

 

[paulk]

I guess if your gonna run it LOUD all day you better have the $$$ to replace it when it blows. Hear that, Paul? Weeeeeeeeeee$$$$$$$$$$$$$$

I have insurance which would cover an engine rebuild until 75k miles however can't go crazy with modding. So far JLT CAI & Borla Stingers though

 

[chuckstang]

This thread hurts my head and makes me wana cry

 

[Taz]

Care to set everyone straight so we don't perpetuate any myths? If you have some information, please share it. That's what the interweb is for.

I would, but you're not worthy, so I won't

 

[lemosley01]

I was reading the CobraRed01's thread from CC and looking at it, I can't figure out why Ford decided a DOCH would be a good idea.

I mean look at this from post 37 by Demon:

Off the top of my head an all iron assembled 351 weighs 510lbs, a 302 is 460lbs, the SOHC modular was around 520lbs and the DOHC was somewhere closer to 600lbs. I haven't had an opportunity to weigh these myself so I can only go off what I'm told. I don't have any numbers for race trim, but I'm assuming my motor (aluminum block, aluminum heads, aluminum internals) would be signficantly lighter. I think I read somewhere that the Dart 351 block was around 65-75lbs lighter than a production counterpart (the discrepancy is based on what year 351 block you go with, as the older ones had thicker journals I believe).

Hmmm...let's see, the Cobra motor weighs 90 lbs MORE than a 351 if these numbers are accurate.

I'm PRETTY sure (this is sarcasm) that a 351 could be made to output more power than a 281 AND it has TORQUE. To top it off, parts are cheap(er) and it is considerably less complex.

Ford could have put more R&D into the 302 and made it output more power than the DOHC 4V and it would still weigh less.

To sum it up: 351 = less weight + more power + more torque = teh win. WTF?

Anybody have any insight into what was going through the minds of the decision-makers at ford?

 

[Taz]

Goddamnit! See, that's the kind of fiction I'm talking about. Dry weight of 4V 4.6L modular, complete from TB to oil pan, but less flywheel, is right around 400 lbs

T-

 

[lemosley01]

Goddamnit! See, that's the kind of fiction I'm talking about. Dry weight of 4V 4.6L modular, complete from TB to oil pan, but less flywheel, is right around 400 lbs

T-

Fine. When you see stuff like this, let us know, instead of making snide comments about 'fiction'. Oh, I forgot. We're not worthy. oke: :bowdown:

I checked the Corral and 400 seems to be about right (unaccessorized) based on other people's experiences. Maybe the post from CC was talking about with all accessories or maybe he was using the 03 Cobra engine weight. Dunno. It's a very old post and his link is no longer working.

http://www.corral.net/forums/showthread.php?t=581420&highlight=engine+weight

http://www.corral.net/forums/showthread.php?t=582998&highlight=engine+weight

 

[Taz]

Fine. When you see stuff like this, let us know, instead of making snide comments about 'fiction'. Oh, I forgot. We're not worthy. oke: :bowdown:

That's right. Now, go to your room.

oke: oke: oke: oke: oke:

 

[Serpentor]

not to get into another engine flame fest, but how much does and LS1/LS6 weigh? just wondering