Low End Torque

[AWD-Turbo]

I’ve got a 5EAT with DP, UP, TMIC, and TDC map.

 

There is definitely an improvement in pull down low over stock. There’s a much bigger improvement through the middle of the powerband. Look at any before / after dyno graph of stock vs stage x (auto or manual). There will be some improvement down low, but most of it will be at higher rpm’s. This is just the nature of a turbo engine – you need exhaust flow to get the turbo spooling.

 

If I ever need some power from a roll, its just a quick downshift away. After modifications, the 5EAT is seriously fast, but its still an auto. Manual transmissions have a different feel and fun factor aside from the speed. Both cars are fast; decide what you prefer to drive.

[problemcat13]

Thanks. I'm going to see if I can test drive an MT and AT this weekend to compare. I just know I'll be moving around and I'm afraid I might end up in a city with a 90 minute stop-and-go commute. That, and the wife, are really the only reasons I'd buy an auto 'cause I've always been a manual for fun guy.

 

Or maybe I am getting lazy!

[problemcat13]

Alright, got to test drive the MT. Yeah, once a manual guy, always a manual guy I guess. Who knows what I'll do. Two points though:

 

1) the MT does allow you to get a better launch, even when you're not drop clutching it. What I mean is you can ride the clutch enough to get a quick launch without just dropping it, whereas with the auto it seemed that either you powerbrake for a drop launch or you don't get a good launch.

 

2) the auto just isn't as smooth in auto mode. What I didn't like is that if you wanted to accelerate to merge and pushed on the gas, it would drop two gears and LAUNCH you, which isn't always what you want if you're trying to fit in between two cars in the next lane. I guess I should have used the 'auto-manual' mode because I'm sure you could keep it in 5th or 4th to smoothly accelerate as you would in a manual.

 

WHY CAN'T MY WIFE JUST UNDERSTAND THAT DRIVING AN AUTO JUST IS NOT THE SAME?

[SBT]

The thing about Subarus, and this has been both my experience with all of the fuel injected models that I own/have owned, if you want max acceleration - especially on the autoboxes - don't hammer the throttle. Give it a jab, because there's quite a bit of torque available off-throttle and once you're above the 2500/2800 RPM point, then roll on the throttle all the way to WOT if you want. They all - NA'd and TC'd - tend to "bog" if you hammer it out the gate.

 

And I went back and re-read this entire post to make sure I understood what the OP was asking and while it was mentioned once or twice, gearing was never really brought into the discussion. I don't want to completely dissect the direct correlation but here's the gear ratios for the 5MT 2.5i and the GTs (sedans and wagons) - thank 7Stars and Sube555.

 

2.5i manual

1st 3.454 / 13.47

2nd 2.062 / 8.04

3rd 1.448 / 5.65

4th 1.088 / 4.24

5th 0.780 / 3.04

FDR 3.900

 

2.5GT manual

1st 3.166 / 13.02

2nd 1.882 / 7.74

3rd 1.296 / 5.33

4th 0.972 / 4.00

5th 0.738 / 3.03

FDR 4.111

 

As you can see, the LGT stretches its legs a bit more from 1st to 4th with 5th being about the same. I'm sure the GT ratios are designed to keep the huffer huffing in the ideal sweet spot for each of the gears. The 2.5i, OTOH, is running probably about 200 RPM faster per gear and that COULD make it seem like it's coming onto its TQ faster as it approaches its sweet spot.

 

On the basis of gearing alone, and everything else being equal (including tire size), looking at the 3.04 (2.5i 5th final gearing) and the 3.03 (GT 5th final gearing), the LGT is going to top out further up the speedometer than the 2.5i. But the big difference will be how fast it gets there as it will have more HP/TQ available earlier in the RPM range, and then continuing higher into the RPM range than the 2.5i.

 

Just my .02

 

SBT

 

BTW - dialogue is more helpful than discussion. Dialogue is collaborative and additive whereas discussion comes across like drummers beating their drums across a table at each other. I'm more up for a dialogue any time.

[john_knoxville]

Also at the point where 5th is doing 70...you are talking about almost 3k rpm...therefore the GT is in its powerband with the turbo spooled

noob TC question: what does "turbo spooled" mean? its spinning?

 

am i correct in thinking that the turbo is indirectly tied to engine RPM, and instead directly tied to exhaust production? i.e. if you are engine braking with your foot off the gas and your LGT is still winding down to 3K rpm, your turbo is producing no boost, correct? at that point, is it still spinning, or is it just "primed" to begin spinning faster right away b/c the amount of exhaust produced by the engine is significantly higher at that rpm range should you resume acceleration?

[Two-Five Sti-L]

noob TC question: what does "turbo spooled" mean? its spinning?

 

 

turbo spooled = making boost

 

fyi, the turbine wheels are constantly spinning once engine is running. However, due to the low volume of exhaust gases in low rpms, the spinning of the turbine on the exhaust side is not quite enough to extact and compress large volumes of air being drawn in, which results in "turbo lag".