I'm pretty new to the fwd world so I'm trying to figure some things out.
1) On my rwd when I changed the final drive to a 4.10 differential I ate up all my gears faster making them shorter. The final affected all of my gears. Is it the same on a fwd? Can you swap out the final drive like a rwd. I'm sure it's not as easy. Wouldn't swapping out the final drive to a higher ratio shorten up all the gears just like a rwd?
2) I've got a 97 gsr. Does the ecu control spark timing. Does it retard or advance the spark based on conditions? How does it do it?

 

yes and yes. it controls timming based on air intake temp and knock sensor

 

If you have a gsr tranny you won't want to go any lower than the gears that are already in there.

 

How does the ecu change the spark timing when the rotor/distributor is mechanical and seems unadjustable to me. I'm guessing there's more to it than that though.

I think you're right about not going lower but what about people talking about b16a tranny's and being faster?

 

it modifies when it sends the spark signal...

the rotor has a pretty wide contact patch so there's a good 1-4 degrees of adjustability by delaying or advancing the instance of signal from the ecu.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by quik1 &raquo;</TD></TR><TR><TD CLASS="quote">If you have a gsr tranny you won't want to go any lower than the gears that are already in there.</TD></TR></TABLE>

Why not? Shorter gearing is always better unless going for top speed or fuel economy.

 

You don't want to go to low or that will make for slower times too. I think that b16 and gsr trannies are already pretty low but thats just my opinion, there may be a better gear setup out there just haven't heard of many people going lower than the b16 gearing.

 

Being at the top of your last gear at the end of the 1/4 mile would be ideal to be fastest, assuming you can get traction.

 

Fueling & Timing needs are 'first' based upon MAP & RPM, since were dealing with a Speed/Density metering system here. Other sensors, especially the ECT, do have an effect on timing as well.

In order to create a spark, the ignition coil must first be saturated. This is done by providing a ground to the ICM, ignition control module. When the spark is needed, the ground is released from the ICM allowing the magnetic field to collapse (it collapses faster than it builds). So, to advance spark timing, the ECU releases the ground earlier relative to crank position (simple explanantion).

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RyanCivic2000 &raquo;</TD></TR><TR><TD CLASS="quote">

Why not? Shorter gearing is always better unless going for top speed or fuel economy.</TD></TR></TABLE>

You ever driven an S4.... WAY TOO SHORT

You barely have the clutch out by the time you have to shift again... it SUCKS.

I'll take more power and longer gears ANYDAY.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NonovUrbizniz &raquo;</TD></TR><TR><TD CLASS="quote">

You ever driven an S4.... WAY TOO SHORT

You barely have the clutch out by the time you have to shift again... it SUCKS.

I'll take more power and longer gears ANYDAY.</TD></TR></TABLE>

Off course, there has to be a balance between power and gearing. Getting the best gearing is not as simple as people think, there has to be a lot of calculations involved and you have to consider the variables that the car is going to see.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NonovUrbizniz &raquo;</TD></TR><TR><TD CLASS="quote">

You ever driven an S4.... WAY TOO SHORT

You barely have the clutch out by the time you have to shift again... it SUCKS.

I'll take more power and longer gears ANYDAY.</TD></TR></TABLE>

If you could drive like this....
http://www.hondata.com/media/er320by240.mov
...you won't complain about short gearing.

He was almost to the top of fifth at the end of that 1/4 mile run.
I will say it once again....being at the top of your last gear at the end of the 1/4 mile IS ideal assuming you can get traction. Short gearing for drag race is better...always.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RyanCivic2000 &raquo;</TD></TR><TR><TD CLASS="quote">

If you could drive like this....
http://www.hondata.com/media/er320by240.mov
...you won't complain about short gearing.

He was almost to the top of fifth at the end of that 1/4 mile run.
I will say it once again....being at the top of your last gear at the end of the 1/4 mile IS ideal assuming you can get traction. Short gearing for drag race is better...always.</TD></TR></TABLE>

I'm just talking about for driving it...

I drove the S4 and it was disquisting how short the gears were... I'm sure it's great for 1/4 mi. but it's lame on the street...

it's like final drives... my buddies mustang was sooo lame.. topped out at like 110.

I'm sure it's great for your quater time but on the street you'll get you butt handed to you... eventually (IE they catch up.)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NonovUrbizniz &raquo;</TD></TR><TR><TD CLASS="quote">

I'm just talking about for driving it...

I drove the S4 and it was disquisting how short the gears were... I'm sure it's great for 1/4 mi. but it's lame on the street...

it's like final drives... my buddies mustang was sooo lame.. topped out at like 110.

I'm sure it's great for your quater time but on the street you'll get you butt handed to you... eventually (IE they catch up.) </TD></TR></TABLE>

I'm sure all the car companies have driving 120mph on public roads in mind as they design their cars....

 

I wasn't talking about top speed. I am talking about drag racing (1/4 mile). Personally, even in a street race I wouldn't go over 110-120MPH it's too risky.

 

But once you are at the top of fifth gear that leaves no room for improvment if its just a race car low gears are a must but anything street driven you will want something bareable. At highway speeds on a b16 you are already reving your engine pretty high and the gas mileage sucks.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aron Parsons &raquo;</TD></TR><TR><TD CLASS="quote">

I'm sure all the car companies have driving 120mph on public roads in mind as they design their cars....</TD></TR></TABLE>

You don't think that the s4 was designed to do 120 plus on the autobahn?

imo the gears are TOO short.. that's all... especially on a turbo... by the time it kicks in it zips to redline like nobody's business... too fast... it was hard (for me at least) to get the most out of any gear without hitting the revlimiter... it just goes through the gear too fast.