ScionFred

iTrader: (1)

Cams, larger valves and head work should cost you around $3000 and possibly get you to 225 whp and 200 wtq with header, full exhaust, CAI, Unichip, etc. Add another $500 to get the Unichip re-tuned for the cams. Add the cost of the header, exhaust, CAI and Unichip and you're looking at $4000-5000.

A $5000 turbo kit can easily have you making 350 whp and 350 wtq. It's easy to see why so few go the NA route past the usual IHE point. Of course there are other things to consider such as clutches, trans, etc. with a turbo that you don't have to worry about with a low power NA build.

There's always the $4000 250whp/wtq turbo option I've mentioned before. Descendant tuner kit, 440cc inj's and gauges. Actually since you already have the Unichip, you could use larger inj's, add $500 for a tune and make 300whp/wtq pretty safely on the stock block. I forget, are you MT or AT?

TrevorS

iTrader: (1)

Yeah, after you mentioned the SSE I spent time learning about it and looks like it's calibrated at least down to 4 in-Hg, and so probably could be used N/A. That's what got me wondering how the ECU already behaved and suspecting enrichment was likely already part of its load trim. If it's already dropping the AFR as far as 12.5, then it's hard to imagine even a switched stage 2 mod being desirable -- over-enrichment would waste fuel, risk the piston rings and cylinder linings, and probably accomplish little in terms of performance. Boost is a different situation since that begins well before WOT, it just extends the intake manifold range to include positive pressure -- the SSE providing an engine protection the ECU isn't programed for. I imagine my Eclipse ECU has that boost enrichment trim already in it's map. Very interesting stuff!

I'll have to do some reading up on header porting. Trouble is, I suspect it's necessary to strip the head in order to do that safely (no particles sneaking into inconvenient places), so that's liable to be shop cost for both the strip and the rebuild. Cams are probably reaching a bit and since most that fool with this stuff are looking for peak HP, not low to midrange torque -- probably especially expensive . Course, the counter to all this is I rarely ask for the performance available now, and even with a largely gentle throttle foot, mpg is impacted. Though as I said, interesting stuff.

TrevorS

iTrader: (1)

Just a quick update. No luck finding a 2AZ-FE head porting article yet, but still looking. Did find a price example for having a particular shop in CA do a P&P for stock head components -- apparently $700. Also found the price for a Brian Cower N/A or F/I street camshaft for stock valves is $600 (also requires an install kit). Seeming a tad expensive for the serious cheapskate ! Also, no info yet what HP & torque improvement is realizable via a P&P alone.

PS. I haven't spotted any endorsements of it yet, but if anyone's interested in the Bill Gude 2AZ-FE performance package, here's the website:

http://www.monstermarketplace.com/sc...ion-tc-xb-2-4l

TrevorS

iTrader: (1)

From reading threads touching on professionally ported heads and after market cams, the message I'm getting is cams are good for higher end power, but hurt lower to mid torque, plus porting the head also tends to hurt torque -- the more extensive the port, the more loss of lower to mid torque.

That really isn't sounding too attractive to me, though I don't yet understand why porting alone would hurt torque (OE VVT-i and cams).

ScionFred

iTrader: (1)

Well there is no over-enrichment because the ECU really does ignore the O2 sensor in open loop. Adding the SSE had zero effect on my open loop AFR, only closed loop.

TrevorS

iTrader: (1)

Yes, there's no over-enrichment if the ECU is truly OL, but if it's enriching as part of its CL map, then there could be. Given a wide-band sensor (allowing accurate tracking well away from 14.7:1 AFR), I don't see why it would be in any hurry to go OL. I'm not saying it doesn't go OL, just that it seems unlikely it would automatically go OL with a wide-band just because the engine operating conditions require a richer than 14.7:1 AFR. Should this be the case, then it seems to me messing with N/A O2 sensor readings could cause over enrichment. The "Stage 2" GTE I linked has a slide adjustment marked "economy" at one end and "power" at the other. I'm guessing if the engine starts to stumble with a maxed "power" setting (over enrichment), the procedure is to ease it back until the engine becomes stable under heavy load.

TrevorS

iTrader: (1)

Planning to continue poking around, but this Wiki article provides a lot of insight into head intake/exhaust passage porting:

http://en.wikipedia.org/wiki/Cylinder_head_porting

Another issue is material removal within the head cylinder domes may improve flow, but it also results in increased volume and reduced compression. A fix could be to shave the head a little to compensate, but that could also result in inadequate valve-piston clearance. Tricky stuff!

Seems clear that if low to mid torque is going to be preserved, it's necessary to be exceedingly careful about any porting work on the intake side of the head -- and not even smoothing and polishing is safe in the neighborhood of the injectors and intake valves (the 2AZ-FE uses a tumble design to improve air flow into the cylinders and passage shape effects that, plus some wall roughness assists evaporation of any residual fuel). I'm guessing turbulence reduction by smoothing any misalignment of the runners to the head could be permissible as long as there's no particular increase in port dimension. However, traditional HP oriented porting where both sides of the port are matched to the typically larger gasket openings would be a bad move. My takeaway is, even though porting may significantly improve flow (though not necessarily), it's very possible to not only not improve, but actually impair engine performance. Interesting!

ScionFred

iTrader: (1)

There is no CL enrichment with our ECU. There is 14.7 in CL and 12.5 in OL and nothing in between. Remember that when the SSE is active, it's altering the wide band O2 sensor signal to tell the ECU that the AFR is leaner than 14.7. The ECU never sees any enrichment. It sees 14.7 when the AFR is actually whatever AFR you set the SSE to provide. AFR is not factored in by the ECU when determining when to enter OL, only load.

I imagine that the stage II GTE works the same as the SSE by modifying the oem wide band O2 sensor signal to the ECU. It tells the ECU that the AFR is say 16:1, the ECU then adds fuel to get back to 14.7 however this is actually say 13.5:1 now. This can easily be monitored using a wide band AFR gauge and a scan tool. E.g., when my SSE is active I see 12.3:1 on my UEGO gauge and see 14.7:1 on the scan tool. There will be no change in heavy load AFR since the O2 feedback is ignored by the ECU in OL.

TrevorS

iTrader: (1)

OK, so you said specifically the ECU doesn't support any AFR other than 14.7:1 (regardless of engine load conditions). In the ECU parlance then, there is no such thing as enrichment, only 14.7:1 closed loop plus an open ended open loop mode. Yes, that surprises me, but if that's the way it is, then that's the way it is !

ScionFred

iTrader: (1)

I've heard that Porsche stays in closed loop and changes AFR based on load. This seems like a better approach to me but for whatever reason, Toyota chose to use closed loop only for low load conditions. Perhaps because the average Toyota probably spends 99% of it's time in CL. I imagine Porsche isn't the only manufacturer to use O2 feedback in high load or alter AFR in closed loop but I'm not sure who does what.

We can still have CL AFR enrichment but only when we modify the O2 signal and effectively lie to the ECU about the measured AFR. Luckily for me Toyota's method works out great for my setup. 12.5:1 would be too lean for me to safely run 6 psi boost but by adding larger inj's I ended up with 11.5:1 in OL. Were I to add even larger inj's the OL AFR would be too rich without additional management. 440cc started as a best guess and turned out to be ideal for my application.

TrevorS

iTrader: (1)

That's great the 440s worked out so well, good guess ! Reminds me of the 1G Eclipse MAF upgrade where a 2G MAF is installed with larger injectors so the OE ECU will still control FI properly.

I guess having an OE wide-band is convenient for those few who choose to go F/I, but it seems odd Toyota specifies one if they're not going to use it (could have been included with a TRD supercharger). If they do it, I wouldn't be surprised if most manufacturers do it, so maybe it's part of the OBDII world so AFR can be monitored/logged for diagnostic purposes. Otherwise, I'd think they'd just go narrow-band for both since it's cheaper. Could be CL enrichment is reserved for performance cars, wonder if the zippy Honda's have it ?

DJ_FroZone

iTrader: (2)

I'm AT sadly. the funny thing is my buddys boosted TC RSMILLER hits around 225 to the wheels now. and the amount of speed is NUTS. so if i got that doing cams/head work. i would have a slight advantage as i would have no lag time. second i floor it it goes. though i do love the sound of blow off values. such a wonder full sound.

ScionFred

iTrader: (1)

I think Toyota uses a wide band for speed and accuracy. Narrow band O2 sensors are slow and inaccurate. When the AFR goes rich or lean it doesn't really tell the ECU how rich or lean it is. The ECU has to guess how much fuel to add or subtract. With a wide band the ECU reacts faster and more accurately determines how much fuel to add or subtract. The WB O2 allows Toyota to maintain stoich AFR much more accurately than it could with a NB O2. This is very important for clean emissions and fuel economy.

From what I gather most manufacturers use closed and open loop states much the same as Toyota. Porsche being the exception rather than the rule. Honda also handles CL and OL like Toyota. It appears to be the OBDII norm.

ScionFred

iTrader: (1)

Actually your buddy would have the advantage even if you both had the same whp. With a turbo he'll have a much wider powerband and a lot more tq. The N/A engine will have a narrow powerband peaking in the upper rpm range and would greatly benefit from extending the rev limit. An N/A build is also much more suited to a MT than a AT. Your N/A engine would be more like a Honda. You also need more gear ratios to keep it in it's narrower powerband. A 6 speed MT would be great.

Honestly I think adding a turbo is much better than heads and cams for a number of reasons. It's easier to install and much easier to remove when you sell the car.

Also, to hit 225whp N/A would most likely require higher compression pistons as well. So you'd need headwork, pistons, larger valves, cams, valve springs, 93 octane, extended rev limit, intake, header, full exhaust, balance shaft delete, pulleys, tune, etc.

DJ_FroZone

iTrader: (2)

haha well ***. did i ever mention how much i love you two.i basically ask all the questions the lurkers dont want to haha

ScionFred

iTrader: (1)

I love you too Bro. TRD Sparks has the Descendant Tuner kit on sale for $2850 and they accept credit cards.

DJ_FroZone

iTrader: (2)

wait wait wait.

http://trdsparks.com/displayparts.ph...&parts_id=1336

yes?? for at??

DJ_FroZone

iTrader: (2)

next summer man. next summer.

TrevorS

iTrader: (1)

Unfortunately, that's just the installation kit, doesn't include the limited slip differential itself ! You need both!

http://www.trdsparks.com/displaypart...&parts_id=1310

.

ScionFred

iTrader: (1)

Not to mention the AT to MT swap!