Sciaru BRZFRS (BreezeFrees)

  • Thread starter Thread starter Azuremen
  • 5,613 comments
  • 442,483 views
Vivid Racing: race like a porn star.

Anyway, what's up with that dip in the curves at 4000? Is that when the secondary injectors turn on? Do you have a map of the mix ratio through the rev range? Would be interesting to see if it gets rich at that spot and then leans out again as the revs keep climbing.
 
Last edited:
There was also Cobb Surgeline dyno video that got taken down for some reason. I think they have AWD Mustang dyno.
attachment.php
 
Omnis
Vivid Racing: race like a porn star.
Click to expand...

Not sure what you mean but if you are referring to their tuning style, I agree on some parts. I'm going to be very vocal about what gets done to this car though.

Pretty sure I've got the wheels picked out, so hopefully they continue to listen to me and go with them.
 
I don't know why you're saying Insideline's dynos are always high. They use the same Dynojet that everyone else uses... and sometimes a Mustang for kicks.

The Mustang really reads low compared to the Dynojet... ask old timers and they'll insist the Dynojet is way too high. But none of that matters. What matters is that compared to other cars on Mustangs and Jets, the FA20 seems to be producing exactly what the sticker claims. 173 on the Jet is about what you'd expect from 200 bhp. 155 on the Mustang is also what you'd expect from 200 bhp (as stated by R1600T).

-

The dip is no mystery. Lots of cars come with it now. With electronic engine and ignition mapping, they program all naturally aspirated cars with a good wad of torque at around 2,500 rpm, then pull back the timing and enrich the mixture at 4k rpm. I've seen it on dozens of different cars now. Part of it is likely down to passing EPA testing (which specifies an exact shift point for manuals and exact acceleration rates). Giving the car more power at 2,500 rpm makes it easier for the testing driver to match the EPA required rate with lower throttle openings and less fuel.

At 4k rpm, there's no need to do this, so they lean it out a bit for better highway economy and pull some timing. Because Americans (and those of us with highways nearby) like to cruise at 80 mph, 4k rpm is important for maintaining good real world economy... cutting a hole in the torque curve there means that the car will sit between 3500-4000 rpms comfortably and will not accelerate out of that sweet spot towards higher engine and road speeds.

-

And if you don't want to put up with all that crap... you can simply rechip or retune the car and voila! The hole is completely gone, giving you a flat torque curve.
 
Wait, you said they enrich the mixture and that they lean it out at the same point. Which did you mean? Doesn't leaning out the mixture save fuel and make more power at the same time? Why make it rich right there?

And who the heck cruises at 4k RPM? Below 3k is cruising.
 
Omnis
And who the heck cruises at 4k RPM? Below 3k is cruising.
Click to expand...

Depends on gearing. My old six-speed Fiat cruised at about 4k at 80mph, about 3.5k at 70mph. Think my 5-speed Miata was fairly similar.

I'd expect 4k is a bit high at an 80mph cruise in the BRZ, but the 3k or so when the torque starts dipping in the BRZ may not be, so Niky has a point.
 
I'm talking 65 brah. What part of the powerband gets you the most fuel efficiency, regardless of wind resistance?
 
Sorry, was looking at two different dynos, as well as reviewing several others that I've seen (both in person and online) recently. The Lancer 4B11 does this. The last two Hyundais we tested do this. The Spark does this, too.

Strategies differ wildly... Some enrich the mix a bit, presumably to keep from knocking on bad gas, others lean it out and pull timing... But by and large, the trend is to pull torque starting at 3k then to feed it back in after 4k. This discourages you from going over 3k when you cruise... Keeping you at 60-70 or thereabouts, depending on the gearing.

And it's ALL engine tuning... Because when we rechip these cars, we gain about 5-10 hp up and down the powerband, but get a fat 15-30 hp in that rpm hole.

It's the only reason I can see for doing this... as running significantly richer or leaner than 14.7:1 would compromise both emissions and economy.

So... recap... Boost power and lean out mix at 2.5k rpm for drivability and for EPA testing, which mandates shift points for manuals... Pull back power from 3k to 4k to encourage more economical driving.

Sneaky bastards. :D
 
My car only does well at low speeds. 4th gear at 40mph or 5th at 45-50mph will get me around 30mpg. Go outside that small window of economy and everything drops down to about 21mpg... Get on it like you wanna have some fun and 16mpg is closer to the norm. :trouble:

That's on a 2011 so it might help shed some light on the subject but then again Im talking about a turbo 2.5, not a NA 2.0. :indiff:

I still feel like the K20 will be my measuring stick for the brz/frs engine.
 
niky
I don't know why you're saying Insideline's dynos are always high. They use the same Dynojet that everyone else uses... and sometimes a Mustang for kicks.
Click to expand...

I can line up 10 dynojets and run the same car on all of them and the results will all be different.
Only way to have comparable data is to test all cars on the same day on the same machine, but since we can't do that, it would be best to test all cars on the same machine with the same calibrations. That's why insideline runs are always high but can be compared to all other cars taken on the same machine.
That's why it's ridiculous when IL runs a base tune, only has a 5% DT loss and they go claiming the car is horribly underrated from the factory or the commentors jump to that conclusion.
 
dsgerbc
Volk G25's look nice on this car...
Click to expand...

Trying to get them to go with Gram Lights 57Xtreme. After some discussion, 19's are probably doable and really don't look that huge.

19x8.5 up front, 19x9.5 out back.

Edit: Except those are not available yet. :(

Guess they're going to wait though...
 
Last edited:
R1600Turbo
Trying to get them to go with Gram Lights 57Xtreme. After some discussion, 19's are probably doable and really don't look that huge.

19x8.5 up front, 19x9.5 out back.

Edit: Except those are not available yet. :(

Guess they're going to wait though...
Click to expand...

Would it look like this?
gallery_12-590x271.jpg
 
Yeah, those are them. There's a better photo here (<-- full size version) that shows a couple different size's. A full square 19x8.5 combo on the BRZ, and a 19x8.5 / 19x9.5 combo on the black 86.

6973776232_3da9030e98_b.jpg
 
See, that photo is a bit deceiving though. The black 86 wheels look physically larger than the silver BRZ. It's almost like the BRZ has 18's on it, but apparently they are 19's as well. I'd like to go 18's, but this wheel is only available in a 7.5" width if we were to go that route.

Edit: I mentioned a 5x100 to 5x114.3 spacer conversion but they wouldn't have it...
 
Last edited:
eSZee
I can line up 10 dynojets and run the same car on all of them and the results will all be different.
Only way to have comparable data is to test all cars on the same day on the same machine, but since we can't do that, it would be best to test all cars on the same machine with the same calibrations. That's why insideline runs are always high but can be compared to all other cars taken on the same machine.
That's why it's ridiculous when IL runs a base tune, only has a 5% DT loss and they go claiming the car is horribly underrated from the factory or the commentors jump to that conclusion.
Click to expand...

It's the same with any other dyno. And the more you try to correct, the bigger the variance gets.

The Dynojet's popularity, despite the fact that the typical inertial sweep test is inherently flawed versus a braked sweep, is due to its relative repeatability.

I still don't see the problem. Both Mustang and Dynojet results are within the range I'd expect a 200 hp atmo engine to be at... Neither under-rated nor over-rated.
 
Well we have certain suppliers that we work with and get large discounts with, so they are trying to stay with those. Our main choices would be from Rays, Volk, Gram Lights, etc. (all brands marketed by Rays Wheels) The problem we have at the moment is that most of the wheels that fit the lug size are not wide enough for us (most 7.5" width) or specific sizes just released for this car that are not available until next month.

So at the moment I've been told that they are going to wait. For now they are concentrating on exhaust and carbon aero parts like a rear lip spoiler, etc.
 
Yes, but still deciding on that too. KW just announced a setup, but it's their Stage 3 package with the external reservoirs and they don't want to put anything on the car that is too expensive. One of the plans for the car is to make it "affordable" for people that want to duplicate it.
 
I'd settle for a set with adjustable height, damping and travel...

Don't forget the intercooler scoop hood... :D
 

Latest Posts

Back