zigroid

iTrader: (22)

there are 400+ cube LT5s. theyre just REALLY expensive. they do make a ton of power though.

black_knight

iTrader: (1)

Do they fit in anyone's engine bay, though?

stik6shift93

Actually i believe lingenfelter makes a 415ci setup for them.

stik6shift93

The reason the lt5's had less than desirable track times was because the gearing in them was insanely tall for a 7k redline, they barely break out of second in the quarter.

stik6shift93

I would also add that imo comparing hp/liter is a dumb way to gauge a production engine. A better comparison in a production world would be hp/lb of motor, hp per size of motor, hp per relaibilty, hp/emission, hp/$$..... I would wager that the ls1/2/6/7.... dominate most all other production motors in these manors. In a displacement restricted world, such as that of racing it may be a better gauge however there's no such restriction in the production world.

RussStang

Your info is skewed on the LS6. The LS6 was rated at 405hp/400lb-ft of torque. The LS6 runs up to 6500rpm, and it too has quite a flat powerband. Sounds like you are a fan of the LT5, and want to hate the LS6, but your "facts" are pretty skewed. Its a good thing we don't all live and die by the opinion of some guy in some magazine we don't even know the name to.

RussStang

They fit in the ZR1's.

Never seen an LT5 transplanted into anything else before.

93LT1

The ls6 was not rated at 400 lbs torque as far as i knew, if so please correct me i thought it was rated at 345 lbs torque. Also i love the LS1 and LS6, i think they are the best motors avalable to us Chevy guys that want to take down ford powerplants. But the facts are an LT5 will beat an LS6 mod for mod, it has the same top end with 500 more rpms stock and more bottom end. Im just saying DOHC is going to be better mod for mod. I have an LT1 myself and i love that motor. I think that a pushrod motor is great, we have had them for years and know how to make em run to do what we want, but DOHC is going to win hands down everytime with the same mods. Assuming the same displacement, compression and all. Lets take fords 2v motor in the GT in later years (the 260 hp 310 torque motor) and compare it to any chevy motor of the same displacement. In one hand we have a 9.5 compression motor that ford makes with only 281 cubic inches. The heads are super resrictive, yet this motor makes 260 hp and 310 torque with a perfect idle. I dout any 281 that chevy could make would have these power numbers with a perfect idle. Leteralone have the capability to make tonz of hp by revving. As a motor gets smaller we all know it has to rev to make power, a pushrod motor at that cubic inch and compression would lose hands down to a DOHC motor by far. Although i do not think ford did a great job engineering there Modular motors, they are getting better. I guess all im trying to say is that DOHC is superior and will allways dominate a pushrod motor mod for mod. Money and reality are different though, a DOHC motor is not cost effective and this is why alot of mustang guys that i meet at the races with them all they have is X pipes and maybe an intake and a chip. As to where most chevy guys like myself allready have a cam and head work done, with stroker kits not to far down the road. I love the single cam motor and pushrod motors cause u can get 400 hp and it doesnt really cost u that much. I just wish ford would make a better modular, and i hope chevy makes a modular that is not so exspensive and can be modded as easily as an LS1.

RussStang

Do you happen to have a dynograph comparing the LS6 to the LT5, because I know nothing of the "superior LT5" bottom end. Also, I don't know how much better the LT5 responds to mods, because they are so damn expensive I don't think that is much of a valid comparison to begin with.

Here are your engine specs. Even the LS1 makes more torque than you thought the LS6 does.
http://www.automotive.com/2003/101/c...specifications

Considering that the LS1 makes more hp/L than the 281 2V Ford engine makes, I would bet a smaller, higher revving Modular v8 sized LS1 would make more power than it's Ford counterpart, pushrods and all. Your torque numbers are off for the Ford motor as well. They made 302 peak lb/ft of torque, not 310.

One last thing. In this day and age, I don't think that a OHC valvetrain is a serious advantage to today's pushrod engine, metallurgy being where it is today. Unless we are talking about really high revs. The LS7 was built to be run to 8000rpm reliably, and is a 7 liter motor with a 4" stroke. Revability is largely determined by weight of the rotating bottom end components, and size of the stroke.

Camaro99SS

iTrader: (4)

The 4.8 used in the trucks started out with 255hp and is now at ~ 280 with a truck cam designed more for towing then Camaro duty. With a stock Z28 cam or one from an LS6 where the motor would have a peakier powerband like the 4V Mach 1's or the 3V GT's, the 4.8 would at least equal the 4V in hp and likely have more low end.

Keep in mind that 5.3 heads have smaller ports then 5.7 heads and won't flow as well out of the box, so I can't see them flowing much differently then the 2V PI heads. Also, any 2V 4.6 with or without PI heads has never been known for low end torque. Crown Vics have always been somewhat of a turd out of the hole, and in the Explorer, even worse.

I will admit, I like pushrod motors better then OHC mainly because of the more compact size, but eliminating the pushrod has not been the sole answer to creating a higher rpm motor. All that's needed are guideplates to take care of any pushrod bending.

Also, the Indy 500 car that won back in the mid 90's and generated more power and torque was a pushrod design.

But this is just my opinion.

Jason

stik6shift93

The first year i believe the zo6 was rated at 385/385, 02+ i believe was 405/400. Also i think it's pretty unintelligent to say where the cam is located dictates how well a motor will respond to mods. There's a lot more to do with it. Take for example the 4.6 dohc mod motors, a full blown heads/cam five liter all bore motor puts down 390-400 rwhp, 130rwhp increase for 10 grand. A heads cam ls1 will see a 130-170 rwhp increase with heads/cam for a few grand without even touching the bottom end.
Secondly last time i checked the ls1 didn't have any choppier an idle than a mustang, don't know what you're talking about there. Also you can't compare static compression ratios, ohc motors usually has less cam overlap and have a higher given dynamic compression ratio which is why it only runs 9.5:1. Also i'm pretty sure considering the ls1's really put out 350hp, even at 4.6liters it would still have over 260hp. Also the sohc 4.6s that made 225hp where the ones with bad heads, the ones that were putting out 260 had much better heads.
To be honest i would hate to see gm go to an ohc lsx. I would hate to see what the front end of a vette would look like if they had to stuff an ohc motor in there, it'd look like a brick like mustang front ends. It's be a pita to work on, expensive as hell to mod, cost several thousand more to buy, probably get worse gas mileage, be less reliable, would ruin the weight bias of the vette...........list goes on and on. I believe people think gm's in the past using pushrod motors however don't really look at the full picture, gm knows exactly what they're doing and if they can continue to meet future epa requirements with the lsx motors i believe you will see them around for a long time to come.

Darksol

I remember reading a story about the being of the LS1's life. G.M. didn't know which direction to go in. Pushrod or DOHC. They found that in back to back tests the torque of a pushrod engine was far more favorable that that of a DOHC.

The current Mustang GT makes 300hp and 320lb/ft in a SOHC. NOT A DOHC MOTOR! http://www.caranddriver.com/cars/for...d-mustang.html

The current Q45 from Infinity is a DOHC and in makes 340hp and 333lb/ft of torque.http://www.caranddriver.com/cars/inf...initi-q45.html

And if you doubt that G.M. can compete with 4.6 check out the caddy XLR's 4.6 DOHC motor. 320hp and 310lb/ft. http://www.caranddriver.com/cars/cad...ac-xlr.htmlThe Ford guys that I know dislike the current modular motors . The 5.0 was a better motor.

DOHC motors do not make the torque as easily as the pushrod engines do. They typicly need to be wound out in order to make the power. So while the pushrods make stump pulling power out of the hole. The DOHC motor is bouncing of the rev limiter to leave with the same urgency.

DOHC motors are great motors. I've just decided it like torque too!

black_knight

iTrader: (1)

I refuse to assume same displacement because OHV can run more displacement for the same size and weight of engine. The idea that the motors should be compared displacement to displacement instead of size/weight to size/weight is RICER MATH and you are a FOOL .

RussStang

This I don't understand. What is your specification when you are talking about size? Because an engine with the same block dimensions, same bore spacing, same deck height and same bank angle is going to be enlarged to whatever the cylinder walls will tolerate, regardless of cam location. The bulk of the weight on an OHC is on the top of the motor, in the cylinder heads, and SOHC engines usually aren't all that bulky. It is their DOHC counterparts that are bulky. You can refuse all you want, but there are displacement laws in racing leagues that strictly address displacement as a criteria, and for good reason.

RussStang

93LT1 brought up the 2V 4.6 Ford engines, which made 260hp. The current Mustang engine is a 3V 4.6.

Although I think 93LT1 is wrong in much of his statements, I think you are generalizing too much in your last paragraph as well. DOHC engines can make power down low. It all depends in the setup. Pushrod engines can scream to redline with the same urgency that an OHC engine does as well. These are stereotypes that have been placed on both motors over time that don't necessarily reflect their true natures.

I have been in plenty of DOHC econocars that were clearly tuned for more low end torque than high end power. Ever seen a destroked small block Chevy rev. They rev extremely quickly. Look at Nascar. As much as the racing sucks, the engines are very nice pieces of engineering. Those engines live 100s of miles in anger, and depending on which race they run, are turning 10k rpms.

black_knight

iTrader: (1)

Have you seen a SOHC Ford 4.6 next to an LS1 or ford 5.0?

I don't give a hariy rats @$$ about displacement laws in racing. Production cars are made for the street, and there is no displacement law there. Acting as if there were to say that such-and-such motor is better because of specific output is RICER MATH.

93LT1

I wish Gm would make another DOHC motor that actually had more cubes and high compression. Then maybe make it affordable, and then let the aftermarket come to life with it. There is no pushrod gm motor that will make it to 9000 rpms or even 10k rpms like a ford modular motor can. RPMs are where u make all the hp unless u have a huge *** motor. Anyways, comparing a motor that ford makes to chevy is kinda hard cause chevy does a better job at it. i have seen a few guys online who make 700 NA hp with a 5.4 modular ford motor at 9500 rpms. Granted thats after alot of money but we are talking cams vs pushrods and stuff so i guess money doesnt count lol. In terms of pure efficientcy the DOHC or SOHC is better because u eliminate the pushrod and the lifter in the valvetrain, which eliminates a heavy rotating mass in the valvetrain and also eliminates alot of friction cause by all these components. Its like comparing a 2 piece driveshaft to a one piece really.

black_knight

iTrader: (1)

So f***ing what? Are you here to make RPMs or to make power?

RussStang

Yup, in person. LS1 is smaller. Guessing you are referencing the infamous picture where a Ford 5.0 is sitting on an engine stand next to a DOHC 4.6. Guess what, the SOHC heads are not as bulky as the DOHC heads are. Besides, the Ford engine is not the end all be all of OHC engines. Apparently you have not seen a well packaged OHC engine.
You did not answer my question at all anyway. What are you criteria based on engine size? Bore spacing?

Ok. However, how many people actually give a **** how physically big their engine is, when it has already been installed in the car, and all the hard work has been done? Its pretty amazing how the LS1 weighs less than the Ford 4.6, and yet a 98-02 Fbody weighs in roughly 3400lbs, where as a 99-04 Mustang GT weighs in at around 3250lbs, even with the 2V's iron block.

black_knight

iTrader: (1)

External dimensions of the engine.

That's not the objection. The question is if GM should go with OHC or OHV into the future. The size problem with OHC is that they can't stuff as many cubes into a given engine bay with an OHC design as they can with an OHV.

Uh, huh.

And how much does the Ford 4.6 weigh versus an LS1? In case you forgot, this is a question of which configuration of engine has the weight advantage, not whether the Mustang chassis has a lower curb weight. Unless you want to argue that they were able to make the Mustang lighter because it has an OHC engine.