Jump to content
SAU Community

Recommended Posts

  • Replies 61
  • Created
  • Last Reply

Top Posters In This Topic

i'm no expert, but my transmission guy reckons that there is some power-train loss with almost all automatic gearboxes.

I've heard this is almost non-existent with auto 300zx's. 40% is a bit much, i hear its about 5-10% depending on the car. There might be one car out there with a 40% loss, but i doubt its a skyline.

My previous car was a series 4 auto, it was noticeably slower than my friends manual series 4, although, the fact that my gear changes were very fast benefitted me a lot.

Good luck with your conversion. I only hope it was done properly so u don't have to keep having your car in shop all the time!

I have a feeling it may be a bit of a myth based on some older cars losing massive amounts due to auto. You have to account for a different final drive ratio at the wheels as well.

Most autos I have seen have been at *most* (when tuned) within about 10% of car with same mods, if not same.

well i'll keep yas updated, with quarter times and i'll do a power run, with a bit of a tune

as when i put the manual i had to lower the idle speed, to compensate for the auto's idle.

and i think APC tweaked my standard ecu abit and the timing, so i'll get it checked out and see if its right.

but im pretty happy with the conversion, there was some little bits he missed, with puttin wires back in there position, and dangling wires .

Everything works dash, lights, speedo, and havent heard any whines , or crunchin of gears.

goes good. But as i said there is a noticable difference in power from the auto.

Who knows my auto could of been worned and tired.

its funny that no one has made mention of the driver

allmost any idiot can drive a manual,... and an auto for that fact... but its how well you can drive it

1/4mile times depend alot on the skills of the driver aswell as the performance of the car

yet everyone is saying autos are slower then manuals, and vice versa

hmm

-Ruffels

So its definately an rb25det 5spd gearbox?

I wanna know how they are making any money off it when a descent box is around 1500 and same with a good clutch  :confused:  

thats 3k without any of the other little bits

I'm going to ask these guys how much for an RB20DET manual converison :) If they can do an RB25DET one for $2500 with the gearbox being worth so much, an RB20DET one should be about $1700 or less! :)

the time it takes to change gears with an auto power is lost.

With a shift kit power would move faster as gears are changing faster.

when i put in a shift kit the changes through the gears were alot faster and gave a better 1/4 time thinking about it now though the actual power probably would not increase but the time it takes to get the power to the ground is shorter.

before the shift kit there was always a small hollow spot between gears now every time gears changes it pulls into the next gear with no loss of power unlike it used to.

im not an automatic transmission mechanic so i couldnt say about if there was an actuall power increase but id say that the amount of power lost in the transition is a lot less.

Nah it didnt do anything on the dyno

But with the change of power to the shifts thats the power gain i were getting at compared to what a manual would lose they'd be very similar one would think now.

The best thing about autos though is no paying for clutches :D

A shift kit won’t change the final rwkw, but it will shift a lot quicker than a manual. Old autos lost much of their power (compared to a manual) because the torque converter never fully locked up with the flywheel (there was always some slippage as fluid was pumped through the torque converter) modern autos however do lock up (manually) as the 2 speeds get close together, which reduces much of the difference between the two.

I agree however that an auto should be a few rwkw down if a manual was put into the same car (but we aren’t talking a lot of kw). The other thing to consider is that an auto increases an engines torque (which is more important than kw anyway).

When you also consider:

1. The speed it can change gears - faster than a manual ever will (after the shift kit is installed)

2. An auto is easy to cruise in and copes well with bumper-to-bumper traffic

3. You don’t stall at the lights because the clutch has very little feel (most embarrassing)

4. The cost to overhaul is chicken feed compared to replacing a 3-plate carbon fibre clutch (or any other clutch for high power uses)

5. It leaves your left arm free to play with your girlfriend in the front seat

Unless you are looking at a track application an auto is better in almost every way, and only then until a 6 speed auto is available for the skylines.

i went from auto to manual i had front pipe done

went from 113 rwkw to 120

if that helps

here is no about about it, there is a loss, and i for one felt that when i drove it out the mechanics. big smile on my face- it adds another element to driving, its fantastic working the gears.

i heard of the fella that did the conversion for me, from mates as they went to skool with him and, my mate got his engine converted in his vl with gearbox and rb25det for 7000

i thought it was a good price aswell when i heard, with everything done and drive away

also depends where he gets the gearboxes from, which he prolly gets them very cheap, to make a profit.

with the power,

i was looking for power, but my main concern was ecu options

and havin control of my car , knowing that its not goin to change back around a corner and spin out.

if any of yous are interested in convertin let us know send us a pm and i'll give you his details.

the price was 2500, and he gave me back the auto gearbox, and torqueconverter

and the tailshaft was modded so didnt get that back .

goin to the quarter in two weeks

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Got you mate. Check your email!
    • I see you've never had to push start your own car... You could save some weight right now...
    • Sounds good.  I don't 100% understand what your getting at here. When you say, "I keep seeing YouTube videos where people have new paint and primer land on the old clearcoat that isn't even dulled down" do you mean this - there is a panel with factory paint, without any prep work, they paint the entire panel with primer, then colour then clear?  If that's what you mean, sure it will "stick" for a year, 2 years, maybe 3 years? Who knows. But at some stage it will flake off and when it does it's going to come off in huge chunks and look horrific.  Of course read your technical data sheet for your paint, but generally speaking, you can apply primer to a scuffed/prepped clear coat. Generally speaking, I wouldn't do this. I would scuff/prep the clear and then lay colour then clear. Adding the primer to these steps just adds cost and time. It will stick to the clear coat provided it has been appropriately scuffed/prepped first.  When you say, "but the new paint is landing on the old clearcoat" I am imagining someone not masking up the car and just letting overspray go wherever it wants. Surely this isn't what you mean?  So I'll assume the following scenario - there is a small scratch. The person manages to somehow fill the scratch and now has a perfectly flat surface. They then spray colour and clear over this small masked off section of the car. Is this what you mean? If this is the case, yes the new paint will eventually flake off in X number of years time.  The easy solution is to scuff/prep all of the paint that hasn't been masked off in the repair area then lay the paint.  So you want to prep the surface, lay primer, then lay filler, then lay primer, then colour, then clear?  Life seems so much simpler if you prep, fill, primer, colour then clear.  There are very few reasons to go to bare metal. Chasing rust is a good example of why you'd go to bare metal.  A simple dent, there is no way in hell I'm going to bare metal for that repair. I've got enough on my plate without creating extra work for myself lol. 
    • Hi, Got the membership renewal email but haven't acted yet.  I need to change my address first. So if somebody can email me so I can change it that would be good.    
×
×
  • Create New...