Ideal street torque curve
 

I've been looking at the various turbocharger applications for the Fa motor and was wondering if there were anybody that could enlighten me on something.

Looking at the turbocharged 2.0l DI "ecoboost" motors from Ford and the same type engine from GM they seem to generate a healthy amount of torque early on in the rpm range. (They claim 240 - 260 ft-lbs @ 1700- 5500)

From my perspective the turbo kits that have come out for the 86 cars are more peaky and don't start applying real torque until above 3 or 4 thousand rpm. Does anyone have any insight on how to build a kit that sacrifices a little high end for some street worthy lower end torque? Is this a question of the whole engine package and tuning as well?

Thanks for your input.

For that, you'll need a smaller turbo. Those turbos are going to give out much earlier than a more efficient but larger turbo.

A kit with GTX28 turbo will achieve that. There is not much point in having 250 wtq at 2K RPMs. A gtx28 will give you great torque in the 3K rpm range and carry it over at least until 6K.

Or a supercharger....

Yeah it's called using a small turbo. Those cars also redline about 1400 RPM lower than our cars and have way different gearing. We have 6 speed short ratio gearboxes so having a car making a bunch of torque at 1700-2000 RPM is really kind of useless. There are a multitude of turbo kits out there which will work well. AVO ,SPD, Greddy, Hexon, etc. all use smaller 18G turbos. The GTX28 (Full Blown, JDL, etc.) or EFR6758 turbos (Treadstone/Full-Race) also have good low end and good response.

The electric supercharger is cheaper and really easy to install and gives a good low/mid-range punch.

Why is it useless to make torque at 2000 rpm? It seems that most of my street driving is shifting at or before 3000 rpm, would it not make sense to be in the thick part of the torque curve?

Thanks for your input.

A boatload of torque at 2k rpm would be awesome for traction and your driveline longevity. As was mentioned by others. This car is geared differently than your comparison.


Im on the kw kit in basically the ots configuration. At no point in "street" driving have i needed more torque down low. This is with 235 summer tires.

In "street" situations where from a stop im applying gas to make a corner through an intersection before oncomming traffic, 50% or more extra torque at low rpm would be nothing but a liability.

Go for a ride in conservative fi frz not a top end monster, i doubt any are lacking in power for legal "street" driving

Ive owned and spent a lot of time in the 2.0t vws (used to have an s2+ one). Those have the low end torque of the focus as well. No tears have been shed over the loss of "low end"

The stock motor is plenty torquey at 2k rpms. Having a turbo and giving it heavy throttle at 2k is just going to put unnecessary load on everything and probably cause compressor surge.

I've yet to ride in a turbo or supercharged twin, but my instinct tells me I'd prefer a supercharger for low end torque since I shift below 4k rpms about 95% of my driving. I'd rather feel the power where I usually drive my car rather than have to be driving spirited in order to feel the power. But again, that's just what I assume. Everyone says to go turbo though, so Idk. Hard to decide unless you ride in both I guess.

I'm making 185wtq peak:

http://imagizer.imageshack.us/v2/640...0/836/s8m5.jpg

Disclaimer: Stock pull isn't completely stock, I had HF catted front/over pipe, CBE + drop-in filter.

The idea of making ridiculously high low-end torque was likely brought about by car manufacturers attempting to make their 4 cylinder engines feel like mid sized V6 engines when cruising around town. It comes at a price though....low horsepower output, at least compared to what the aftermarket brings to the game.

The FA20 revs to 7,400 rpms and is therefore geared to utilize that powerband. It is better to have mid levels of torque throughout the powerband. On and engine like this that revs well past 5,252 rpms where tq and hp crossover, you'll be rewarded with big hp as a result.

Don't let anyone tell you otherwise, at the end of the day hp is what is going to make your car fast on the open road, period.

Sometimes people are too focused on having a tiny tiny turbo that hits really hard down low rather than having good mid levels of torque that holds all the way until redline.

Here's an example. If we were let you test drive our turbo set-up that makes useable power to 8k and we changed the face of the tach to show a 5k rev limiter, you'd likely be in love with the powerband compared to a setup with a tiny turbo that gives you boatloads of low end torque only to fall on it's face in the upper part of the powerband.

A big torque surge down low will throw your passenger into her seat when you hit the throttle, but it's big hp that will keep her pinned there. :cheers:

-Toan

Put diesel in it. That's the key.

You need a 6.0L V12 from a 1990 Mercedes S600.

Ooooor an LS3 swap. :)