im probably gonna do a swap to manual but i was wondering why cant they hold the hp? im at 300 rwhp is it cause of the transmission? can the tranny be built up to support the hp? why are most drag cars auto? my buddy's mustang is 500 rwhp and its a auto. is the rx7 just that week in the auto tran?

 

The stock Auto Tranny was just not meant to hold more power.

Can the tranny be built up? Sure, quite a few people have went the route of Level 10 to get a built Auto Tranny, however how much are you willing to invest in the auto tranny? Fully built auto trannies from Level 10 are usually around $5k.

 

so it would be cheaper to swap? i think i can do a swap for about 2500. also how much power will a level 10 hold

 

is there other levels? i only want 400 rwhp. do i have to have a level 10 for that?

 

Level 10 is a company name: http://www.levelten.com/

They can/will build a transmission to hold whatever power you want, if you have the money. Is it cheaper to go 5 speed? Yes. However, some people like Automatics so it's worth it for them.

 

i was told but i dont know if its true. if you take the exact same car with same set up same horsepower. say 300 to rear wheels auto vrs stick that auto will be slightly faster. is that true? i know most people with manual will say no and i dont care cause i like them both but i was just wondering. i know i have raced my auto and from the line i will power break a little and build the boost and when i take off no lag and i hit boost from the line. my car hooks up well but thats how i beat most these cobra"S

 

For anyone who really knows how to drive a stick, no. The older 'stock' auto trannies are not going to be faster if the person driving the manual knows what he's doing. The problem will be most people don't know how to really drive a manual. You can see it the car reports where the auto tranny will usually be a little slower than the manuals in their 0-60 tests.

Now, you can get some of the built trannies that some of the powerful drag cars use which will definitely be faster. I met a guy with a built late 80's Mustang drag car. His auto would do something like 0-70 in its first gear.

Also, the new semi-auto trannies being used by Audi, BMW and Mercedes are a different breed.

 

One reason why the auto isn't upgraded often is the lack of support in tunable ECUs. It's just easier to make and handle the power with the simplicity of the manual drivetrain.

Dave

 

well i know stock manual would be faster than stock auto cause stock manual has more hp but im saying if they was the same hp

 

They are equally powerful in stock form, I believe. Are you thinking of rx8s?

 

The normal review tests are done with the car at the same HP (i.e. they are both at 255 HP stock).

 

I've never driven an auto fd, but most auto cars I've driven don't shift as quickly as a stick. This gets to be less and less of a problem as you spend more on the car, I even think there are quick shift kits made for automatics, but it'd cost a lot more than doing the swap. Not to mention it's just more fun shifting a stick.

 

Mahjik just answered that question, and beat me to my answer

 

sorry i thought stock manual produced little for hp than auto. i didnt know they produced the same. i thought the rwhp was diff. so what does average swap cost labor and all? anyone know?

 

Which swap? auto to 5spd or auto to better auto.

Auto trans are for engines that can afford to lose like 30% in the drivetrain.

 

auto to trans

 

Try calling Rotary Performance in TX: http://www.rx7.com

I know they have done the swap for customers so you can ask them what they charge. I'm not suggesting you get a swap done by them, but their price will give you a ballpark of "shop prices" to get everything done.

 

thanks i will try that

 

1. auto tranny has more driveline loss than manual
2. auto tranny has taller gearing than manual
3. auto tranny has taller rear end than manual

For any kind of street application on an FD, a manual will be faster.

 

Driveline loss is somewhat offset by the torque-multiplier function of the torque converter.
'Taller' gearing is a bane to quickness but a boon to top speed. Also, the seamless and constant boost seen in the auto FD compared to the fall-off that is normal with the manual cars makes up for a LOT.
Overall the times are only a half a second off the manual's times in 0 - 60 and I will guarantee you that 60% of the time someone will "blow" a shift in the manual; as mentioned earlier a lot of people don't really know how to drive a manual at 10/10ths.
Quarter mile times get almost identical in the real world.
And if you build up a nice street ported engine with some extra goodies (nod nod wink wink) the auto is a FUN companion when kept to 300 - 350 ponies or so.
Obviously if you intend to track the car then the auto is less suited. But if you are just going to be daily driving, consider if you REALLY want to go to the hassle of converting over.
In my humble opinion, unless you are going for BIG hp increases, leave it alone and learn to drive the auto in a high-performance mode, it takes practice believe me but a nicely built auto FD in the hands of someone who knows how to wring the maximum out of it will surprise even the most stubborn of auto - haters.

 

I think its funny when people say they "only" want 400 whp.

 

^ Yeah, not to bust anyone's ***** but....most people seriously just TALK about it and will never do it. Hell's Bells....the stock 255 hp is ******' awesome, and SHOULD be good enough for 90% of the people out there, especially when you consider mods-for-more-hp-done-wrong lead to costly failures, costs that once again, 90% of the owners can't afford.

Frankly, I think it is the young-uns that often just don't have a clue, and seem to think that you HAVE to 'mod' a car just....well....BECAUSE!

 

Most of you probably already know this, but the main benefit of autos (as far as drag racing) is consistency. When drag racers get up into the 1000+ rwhp range, a manual is extremely tough to control.

 

to correct you, drag cars aren't auto they are manual gearboxes with multiple disc clutches and air shifters. autos are bulky and like to suck up power because there is alot more rotating mass with hubs, clutches, gears etc tranferring that power down the line vs straight gear to gear in manual gearboxes.

now some drag racers do use auto trannies like the turbo 400 because they can be built to be monsters and hold almost any power level but when you put $100k into a true drag car then weight savings becomes a real issue and a 250lb tranny is going to hold you back some as well as the power loss it will hit you with.

 

Yes, I was referring to weekend racers, not top fuel or funny cars.