The Supras are amazing after 60 mph or so.

Good friend had 2 with over 900 hp. The red one was more like 1,400.

They're the only car I've personally seen take on a prepped liter bike and win. But that's in a freeway roll. On the street,.. from a dig,.. a moderately prepped Subaru or EVO will put bus lengths on them.

 

That's 2 of us.

So far the car has a catless Tubi exhaust (installed when new for the first owner, by the selling dealer)

I have an Accesport in it now. (plus a DSC module and a numeric shifter)

This Winter's round of mods are;
Pin the coolant pipes
Sharkwerks coolant tubes
Sachs 2.5 clutch
BBI clutch slave
GT2RS inter-coolers
D088 turbo inlet tubes
IPD 74mm plenum
Aquamist HSF3 system for 50/50 mix (two 0.9mm jets)
Then custom tunes,.. one for 93 pump,.. and one for use with the Aquamist system.

I have everything in stock except for the Aquamist setup. I'll be purchasing that through an expert in the area in the Spring. he can help me set it up as well.


I'm curious what the real rpm limitation of these engines is? Is it the valve-springs? I hear that the GT3 lifters are the same,.. just that the springs are different. Would swapping in GT3 springs allow me to up the redline to 7,500?

Or do you need rods also?

 

You can set the rev limit higher now without any mods to hardware but a stock or even remapped 3.6 turbo mezger does not make power after 6500 rpm. Many guys with maps on here set limit at 7250 rpm but thats only because its too easy to bump into limiter on a 997 turbo with a manual gearbox.

If you modify rods, camshaft, larger pistons with stroker kits 3.8, 3.9, 4.1, 4.2 then the engine takes on a different power curve. That Evolution Motorsport car in the vid for example posted earlier holds the 1/2 mile record at 219mph - safe to say she's making good power approaching her red line of 8250 + rpm

You should start your own build thread - lots of good advice here on 6 speed online

 

[QUOTE=9e 28;4447309] You can set the rev limit higher now without any mods to hardware but a stock or even remapped 3.6 turbo mezger does not make power after 6500 rpm. Many guys with maps on here set limit at 7250 rpm but thats only because its too easy to bump into limiter on a 997 turbo with a manual gearbox.



Thanks man.

I am told the boost can be made to come in some 300 rpm earlier than it does now with the Do88's, and the IPD 74 plenum, and a good tune that brings in a lot of advance early. (I'm not sold on the plenum,.. but I got one used,... so it's worth a shot.) Wait,. I guess i did get sold on that. LOL

If I can also raise the redline by a couple hundred to 7,200 ish, then that will achieve my goal of increasing the usable power-band by 1,000 rpm over stock. (Stock my car hit the limiter at 6,500,.. at least according to the tach),.. it's like 6,900 or 7,000 now with the Cobb off the shelf Stage 2 map.)

Obviously your shift-points change by gear. The goal being to straddle the mountain so to speak,... shifting out of one gear into the next, so that you are at the same hp / tq level as you left off with in the last gear. Actually,.. even later than that,.. as with each up-shift you loose torque multiplication from the trans. So it's better to stay in the lower gear just a bit longer if you can,.... shifting out of the lower gear at say 25 hp after peak,.. but arriving in the new higher gear at 15 hp before the peak.

That extra rpm really helps in first and second, when the tach needle is swinging around so rapidly,.. and when the space between gears is so much wider that it is in the higher gears. After the first 2 gears,.. you definitely should be shifting before redline. I use the G's function of the G-Tech to figure out the ideal shift-point for each gear. The G's of accel at the start of third for instance should about match where I left off in second. I found that when programming my shift light (Subarus come factory with a light and a beeper in the tach,.. that you can set with a **** on the dash). I would set it a bit early for the 1-2 shift,.. to acct for my reaction time. By the time the 3-4 shift comes around,.. it's on the money,. and for the 4-5 shift,. I wait just a hair after the light. With practice,. the G's of accel will almost mtch on the graph. And with measured shift-times 290 ms (measured from the time the clutch starts to go in, to after the car is back under power) , that's about as fast as you can expect that combination to go.

Anyway,.. we'll see. The car makes plenty of power now,.. it's just that it spends a lot of time off-boost. A stronger clutch that will allow me to shift without being a baby will help a lot,... but early spool is still king in a street car. IMO

And I'm guessing that an extra 50 or so hp will be pretty automatic with the GT2rs coolers,the tubes, plenum, tune and a meth kit. Perhaps even +70? Who knows. For sure I'll put it on a calibrated Mustang dyno sometime next Summer and test it with a stock tune, Cobb stage 2, the custom tune and the custom tune for the meth system.


I plan to. But not until I have something worth-while to post. The install work will happen over a couple of days next month. And then the car will be in storage until the Spring,.. (I live near Detroit).

And my apologies to the OP for SEVERELY jacking this thread.

 

^^ Hi its more accurate to say power drops off rapidly after 6500 rpm on a stock engine so no point really revving beyond that. Interesting to see if you can get a stock engine on 997 turbo to spool earlier than 1950rpm just from a larger y pipe and larger turbo inlet pipes. Stock the turbo makes good power between 1950rpm to 6750rpm so quite a flexible turbo unit. In fact Im not sure there is a more flexible unit but tech has moved on so i suppose there must be. 991 Turbo no doubt will be even more flexible/useable but to achieve this efficiency they've made the headers smaller, VTGS turbos smaller etc, felt thunderously fast to me too straight out the box

 

Not a Y-Pipe,.. I mean the plenum. And not the one that reqires the GT3 throttle body,. but rather the one that retains the stock Y pipe and throttle. The first one on this page. http://www.ipdplenums.com/products/p...os/9971-turbo#

I have been told by a few top tuning shops that the bigger throttle and Y-pipe don't help with spool,. and actually hurt power until you get past about 700 wheel. The Op seems to be right at that transition point where it neither helped or hurt hp,.. but did remove a dip in the midrange fo his torque curve. It will almost certainly help him as he keeps adding hp.



I'm just trying to get them to spool by 3,200. I realize that they have the pure "aero" capability to spool by 2,000 ish (known technically as "Spool threshold"),.. but you can only see that if you brake boost the car in 6th. In the real world,... (I.E. stomping on the gas in 2nd or third),... you'll find they come up at about 3,500 stock. And if you look at the OP's dyno graph,.. his modified ones come up at 4,300 (if I'm reading his graph right).

I know I have a different view-point on what "spool" is. The way Porsche seems to advertises it,.. they consider it 6th gear,.. bucking a head-wind,.. going up hill. But to me,.. spool is when you floor the loud-pedal at 2 grand,.. and then at some point the turbos come up and put you back in your seat. Wherever rpm the tach needle is passing when that happens is what spool is to me (let's call it "effective spool" (A combination of "spool threshold" and "shift recovery"). And it would seem to me that that's the only thing that matters. When does the car haul azz? The brochure doesn't make a car fast. It's either hauling butt at 2,500 or it's not.

The second factor in spool (which I just mentioned above) is the "Moment of inertia" of the two wheels (turbine and compressor). When they're big,.. it takes longer to wind up. (Technically this aspect of spool is referred to as "Shift recovery"). If the turbos start to spin up at 2k,.. but the car has accelerated without the help of boost to 3,500 by the time they pass 1 bar,... well,.. then the "effective spool" is 3,500. At least in the lower gears.

A larger turbo inlet pipe DEFINITELY has an effect on spool,.. as well as the top end. In my last car for instance the turbo lit up in 2nd a hundred or more rpm sooner,.. and was over-boosting by 2 psi until the ECU learned,.. and made corrections to it's BCS duty-cycles.

The biggest help for spool (as I mentioned before) will come from the custom tune. Lots of tricks can be employed in cam timing, fueling and ignition advance to help spool up a turbo. In the Subaru world we would lock the ignition cams full advance for much longer than stock,.. and "lean spool" the turbo. (This is where you run a full point or more lean until the boost passes say,.. 7 psi. The leaner mix will result in higher ETG's,.. which expands the exhaust gas more,.. providing hotter and faster exhaust-gas flow to the turbine,.. resulting in earlier spool. It doesn't hurt the engine as you aren't under much of a load yet. The AFR quickly drops down to your max-power mixture as boost continues to climb).

A couple of tuners renowned on this board have said that on this platform,.. they accomplish most of that with ignition advance. Running lots of it until the boost comes up.

 

 

Maybe it's because I come from a different platform, but man, there's so much bullshi__t going on in the Porsche platform.

IPD Y pipes and plenums are a joke.

And vendors here never prove anything when they claim something. All they want to do is sell you stupid stuff. The only vendors that write anything technical are AMS and Cobb.

 

I don't know anything about OP's car and why the y pipe did or didn't work, but on a lightly modified car like mine, it did give me better acceleration results, particularly 60-130's:

 

What is this thread about again?

 

Tuned STI will smoke your upgraded turbo Porsche bro.

 

+1

 

....and big turbo cars are slow

 

Yes and my knowledge base comes from racing big turbo supras 0-60 from a stop light so I analogized based on looking at dyno plots and graphing lag and so all the others are slow too and can't catch my Subaru kthxbye.

 

I live my life a quarter mile at a time, nothing else matters. Not the mortgage, not the store, not the team and all their bull****. For those ten seconds or less.... I'm free




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