Turbo Kits: Rational boost threshold yet?

[Ryephile]

Originally Posted by raul

....as most people trying to increase power significantly aren't too concerned about cruising RPMs. ....

I still feel you're looking at this from a skewed perspective. Not everyone is looking for "significant" increases just up top. Why disregard cruising RPM when that's where you are 90% of the time? It makes no practical sense to be so myopic. My proposal is focusing on "waking up" the car rather than inducing a Jekyll & Hyde behavior. IMO, most of the "big" turbo kits out there are ruining the experience of the car for typical legal street driving.

A stout 50 LbFt extra across the entire RPM band would be a stout kick in the pants no matter if you're stuck in traffic and just need to tip-in or if your blasting down a twisty stretch of fun road.

[Dimman]

Originally Posted by raul

Not at all. But the demand for an FI kit that focuses on low-mid rpm torque is rather low I would think (maybe we should make a poll to see if there's enough interest generated and get one made?), as most people trying to increase power significantly aren't too concerned about cruising RPMs. Most are happy to downshift for power, since it adds to the joy of driving the car.

So why not address the weaknesses?

[Sportsguy83]

Originally Posted by gmookher

I'm sure visconti will full on advance the timing at 3000 and win some noobie sales with an SC he brings to market, but I dont think I consider johns tuning ethics as safest, but he does produce a stellar dyno chart..

JUST as I was typing this to @gmoohker:


"Keep tiptoeing the Ban line and you are gonna fall face first into it...."


He got BANNED!

[serialk11r]

Sorry to butt in, but is the reason people go turbo that you get more power for the money compared to SC? Maybe the SC kit market needs some more competition so the prices go down and so we don't have to talk about using crippled turbochargers to get the same effect :P Talk of small turbines makes me cringe.

[Visconti]

Originally Posted by Sportsguy83

JUST as I was typing this to @gmoohker:


"Keep tiptoeing the Ban line and you are gonna fall face first into it...."


He got BANNED!

again?

[Sportsguy83]

Originally Posted by Visconti

again?

Yep.... Again, wonder for how long...

[JoeBoxer]

It was neccessary in my opinion you can't try to scare members from purchasing other vendors kits based on where they are made. It was getting real out of hand the last couple days.

[Ryephile]

Originally Posted by serialk11r

Sorry to butt in, but is the reason people go turbo that you get more power for the money compared to SC? Maybe the SC kit market needs some more competition so the prices go down and so we don't have to talk about using crippled turbochargers to get the same effect :P Talk of small turbines makes me cringe.

Maybe, but not always, and FWIW I hadn't considered money within my proposal. I'm not sure why small turbines make you cringe; there's a time and place for most things and I know you're intelligent enough to understand that. If we're "only" talking a 270HP solution, why would you mis-specify a turbo that's "good for" 350HP?

Originally Posted by JoeBoxer

It was neccessary in my opinion you can't try to scare members from purchasing other vendors kits based on where they are made. It was getting real out of hand the last couple days.

I'll only touch on this. I hope he can learn that there are other solutions to problems beyond his own interests [like this thread]. He has lots to offer the community, but it seems he's fallen into the "there's one on every forum" trap where their experience goes directly to their ego and they assume they're Master of the Universe, when that's an impossibility. Not everyone here is a n00b. There needs to be more of this:

We're all here because we appreciate the car. We're not trying to ruin it, but sometimes our boisterous optimism can cloud our vision and produce results that are less than ideal. I only ask that we raise the bar, not lower it.

[serialk11r]

Originally Posted by Ryephile

Maybe, but not always, and FWIW I hadn't considered money within my proposal. I'm not sure why small turbines make you cringe; there's a time and place for most things and I know you're intelligent enough to understand that. If we're "only" talking a 270HP solution, why would you mis-specify a turbo that's "good for" 350HP?

I guess I didn't put it very well, and maybe cringe is an overstatement.

The turbo's natural habitat is boosting the engine's maximum power, because the turbine does the best job of collecting waste energy when it is free flowing. If you throw response out the window, pretty good thermal efficiency gains can be had too. "Small" is relative, and in principle a "small" turbine paired with a very free flowing housing and the right compressor can give a very efficient 270hp setup.

What makes me dislike turbos is that dyno queens aside, this typically isn't what people want to use a turbo for. First of all if you want response, any turbo is by default giving up a few hundred milliseconds or more of transient response time. A turbo that makes a whole lot of boost at low-mid engine speeds is by default restricting the top end, whether or not the torque is falling off or not. It *is* reducing efficiency. Then it gets worse, because some people decide they need more boost in the previously deficient places in the powerband, and then they use a wastegate to vent off some pressure and stop the engine from blowing up. And as you know, typical aftermarket wastegate is not electronically controlled.

At this point, you have the same powerband as a positive displacement supercharger at less cost, but the transient response is worse, there is more piping, the turbo is wasting some energy during daily driving, and you've thrown away efficiency everywhere except at low engine speed where the turbo starts to produce some boost (and this is only at maximum load obviously). Doesn't a Roots blower seem much more elegant to you? Less valves, less piping, better response (probably easier to tune I imagine), and comparable or better efficiency, depending on which blower is being used. The only place it's less efficient is when you stomp on the gas pedal at low rpm, which isn't really good for the engine anyways.

[Ryephile]

Who are we doing this for; "the others" or for the joy of the drive?

Of course a Roots or TVS would be better for response and system "purity" if you will, but that area of the aftermarket just isn't caught up yet. With a turbo setup where you're trying to stretch the bandwidth, you'll rarely have an ideal scenario where you're operating at peak efficiency of every facet of the system at all times, it just can't happen unless you're driving a Toyota HSD or similar. Until the mainstream catches up the concept of "Greenformance", we'll just have to focus on fitting engines like the FA20 to our own needs. Nevertheless, BMW & MINI make it happen with good success in their latest crop of T-GDI engines. They have broad power bands and good response with respectable [but not amazing] BMEP. Like I said, you can't have it all, you can only try to optimize the system the best way we know how. If MINI can get an OEM BMEP of 318 with a broad RPM band [it's higher in practice, but that's with the advertised torque], why can't we as a collective aftermarket? That equates to 257 LbFt at the crank with the FA20. Spread that amount of torque as far across the board as possible and you have a recipe for a super flexible and satisfying powertrain.

@arghx7 pointed out Subaru's next-gen engine and IMO it would be a great fit for a BRZ STI. Personally, I'd prefer an FR-S TRD using a Roots blower setup, but that's just my driving-pleasure preference and isn't solely based in logic.

Originally Posted by arghx7

Basically, OP is looking for Subaru to offer the new turbo 2.0 liter engine in this car

300HP and 295LbFt would be killer. IMO the car doesn't need that much, but that's the torque shelf that would zap the car awake in a big way.

[JP]

I've replaced a TRD M45-based charger on a corolla before with a stock secondhand MY08 WRX TD04L turbo on home-made manifold etc. Totally woke the car up compared to the TRD charger, gave it a much wider powerband and made an additional 30kw at the treads with 3psi less boost. The transient response and general throttle response is as good if not better than the TRD charger setup, the fuel consumption also improved considerably with the turbo setup.

The TRD charger sounded cool, but the turbo setup is much more fun in a daily driver

I like all different setups, but I'll be turbo'ing my 86 with a normal GT28R for response seeing it's a daily driver.

Vid's of the corolla I've referenced are here:

Supercharged [ame="http://www.youtube.com/watch?v=favjur3UDCY"]ZZE122R with TRD Supercharger Dyno Run - YouTube[/ame]

Turbocharged [ame="http://www.youtube.com/watch?v=H5S6hcDXIJo"]1zzfte dyno run - YouTube[/ame]

I'm a big fan of high compression forced induction

[thejevans]

Originally Posted by Ryephile

Mandatory criteria:

*<2,500 RPM boost threshold. I want to be able to cruise at 60 MPH in 6th and get real torque in a timely manner for effortless passing.

You have other gears for a reason. Stop being lazy and shift into 5th or, hell, even 4th, if you want to pass. It's more fun that way anyways.

[Ryephile]

That's enough condescension about shifting laziness. If I'm looking for peak acceleration I'll select the gear that does such. My criteria offers drivability flexibility. If we can engineer a solution that does the job better, why wouldn't you want that?

[DRACHENV6]

^ Ryephile. I like the way you think. Keep us posted.