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A.E.M. in N/A.


David P

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What trans upgrade are you going for?

 

Suprastore sell a kit, I am waiting for delivery.

It is supposed to beef up the trans and give a 'less whooshy' more positive gear change.

 

from reading their site all this "kit" does is up the line pressure it will give short term results but the only proper rebuild kit i know of is from http://www.importperformancetrans.com/toyotaauto.shtml#main the pic illustrates what you get for your $700 compared to some "sleeves" for 99 bucks

however at the power levels were about talking here i dont think it will be an issue

ipt_mas_kit2.jpg

Edited by paul mac (see edit history)
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My thoughts also.

 

This $90 kit has been reported to quicken the gear change, and is claimed to increase the trans bhp capabillity.

 

The faster change should make the VV4 more fun to play with, and a mild beefing up, a new filter and full fluid flush should help to keep the trans reliable with the Suprastick changes and a few extra horses.

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  • 10 months later...

My projects have become tangled up.

 

The original intent was to see how much power and economy could be squeezed from an N/A, then whilst enjoying these gains, to continue on and tinker about with a supercharger conversion.

 

Other than induction prior to the runners, all components are common, and is a logical route to follow.

 

However, it took so long for the hydrogen generators to arrive, to fill in the time I began tinkering with the supercharger conversion.

 

The 17 weeks delayed arrival of the HHO kit coincided with the recent ice age, so it now makes more sense to tinker about making components inside, compared to lying outside under the car freezing my nuts off!

 

Consequently, by the time the weather has improved enough to sensibly get back under the car, the supercharger conversion will be sitting in the shed waiting to go on.

 

Should the Supra pack up, I would have to get out and get under, but I tinker for pleasure not purgatory.

 

As much as I would like to complete my normally aspirated aspirations, it would be dickthippery to fund a comprehensive rolling road session to install and set up the AEM ECU, Aquamist 2C water/meth injection and the HHO system, then to go home, bolt on the supercharger and go back and pay for it to be done all over again!

 

Consequently, I have chosen to compromise.

 

The engine is running very nicely on the stock ECU, with the exception of being too rich when over 4k rpm in open loop.

I have decided to back off the fuel pressure to reign this in as best I can, to try and lean out the AFR to 13:1 at 6.5k rpm and let the ECU learn to sort itself out in closed loop.

 

Then to take it for a run on some rollers and see what it has got.

 

This measured run will be minus the gas flowed runners, phenolic gasket, AEM, water/meth injection and the HHO system.

 

Without these final gadgets and components the numbers achieved will be smaller, yet the results should be more informative to N/A owners, who most likely wouldn’t go to the extent of installing these items.

Edited by David P (see edit history)
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  • 2 weeks later...

The engine is running sweetly @ 14.7:1 in trundle mode, but way too rich at WOT, so try and lean out the air fuel ratio, I have reduced the fuel pressure from 43.5 to 36.5psi.

Whilst at AFR, I had the car run on the rollers, yet it looks as though the £50 spent has only confirmed that I would need to spend 10x that much to have the AEM installed and set up to release the gains.

Here are the print outs that show that even with the reduced fuel pressure, it is still managing to find way too much of it.

 

attachment.php?attachmentid=125530&d=1295356587

 

attachment.php?attachmentid=125529&d=1295356587

js800_AFR_dyno_002.jpg

js800_AFR_dyno_003.jpg

Edited by David P (see edit history)
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Very interesting read, David.. but without flogging a dead horse, have we managed to conclusively substantiate the fuel economy question?

One reason I ask is that I'm convinced that there are many ways to improve the efficiency of either TT or NA systems, and therefore I'm very willing to give your claims a chance - but you've not done anything documented in this thread that most owners on here haven't already (reducing intake temps, exhaust wrap, flowing intake manifold, degreeing cams etc), yet have had results unmatched by other modern cars designed for fuel economy. You've also not given any thoroughly technical answers, besides guesstimates of the effectiveness of your modifications, for the improvements in economy.

 

Any insights you can share?

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As I have explained, due to circumstance my future project has caught up with the current, and as much as I would like to know these answers it would cost me another £500ish to do so, and I haven't got that many £500 notes waiting to be burnt.

 

Maybe the 'curious' can have a whip round :search:

 

The late arriving HHO generators will now be included into my supercharger build, when the weather steadies down enough to allow me to work on the car outside and still feel my fingers, so maybe then a comparison can be made with a similar powered single turbo, or Barneys supercharged Supra.

Edited by David P (see edit history)
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Right, don't explode at me, I just want a technical discussion :)

 

One quick way of telling if some modifications have increased or decreased power is to compare AFRs from before and after. I used this method as a quick initial check on the performance of a reverse staggered cam setup once. The reverse cam setup reduced power, and I could see this quantitatively because my AFRs dipped across the board by about 4 to 5 points, i.e. from 11.8 down to 11.3. It was only above 6000rpm that it started recovering back to what it was with normal staggered cams. The richening of the AFR, with all other things being the same, shows that the cylinder filling is poorer - less air is getting in, so less fuel is being burnt. This in turn means there is less power. I hope you'd agree with these conclusions.

 

If you fit wider cams to an otherwise stock Supra, you will run leaner above 5500rpm. The ECU has no idea that the ability to fill the cylinders has been improved, as its sensor feedback ends at the intake plenum. This shows that cylinder filling has been improved and therefore more power is available (and the fuelling needs remapping somehow to suit).

 

I hope you agree with that as a general rule of thumb. Now, I would have said that none of your mods have improved cylinder fill as otherwise you'd see a leaning off of fuelling, but having taken a second look at those graphs I think the fuelling is so rich, even with the fuel pressure reduced, that something is just plain wrong! Is there a dyno chart showing AFRs from any other NA's around, so we can see if that's normal? Sub 11:1 is too rich for a high boost turbo, never mind NA. You would probably be aiming for 12.7 to maybe 13 if you are avid about power and fuel economy? I imagine you'd recover a lot of power if you could fix whatever is causing the overfuelling.

 

It's not your O2 sensors :)

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http://www.mkivsupra.net/vbb/showthread.php?230114-Lack-of-power-NA&p=2916359&viewfull=1#post2916359

 

Interestingly, this graph shows two things:

1) You really shouldn't be running 11.5 to 10.8 AFRs on a stock ECU so there is something to fix that'll net you more power and better economy :)

 

2) the green line shows a fix where Ryan reactivated the plenum butterfly that improves low and midrange torque. Notice that the AFRs lean off after that fix, showing that cylinder filling improved due to higher intake air velocity - something the ECU can't measure, therefore doesn't alter any fuelling. And as soon as the valve opens at higher revs, the AFRs are identical. Which backs up my earlier statement about measuring performance improvements using AFRs :D

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The vacuum operated torque valve is working fine and so is the ignition.

I have read on the forum that upgrading the exhaust system makes the N/A run rich.

 

The graph shows that the torque drops off dramatically when the AFR runs rich, and as much as I would like to know what it could do with the AEM installed and set up, I can't justify the expense of having the job done twice.

 

.

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Well I think you're wise to not throw an ECU at it, as I think there is an underlying issue that needs sorting to stop it running rich. Remapping around it would just mask the issue.

 

Has anyone ever explained exactly why the exhaust upgrade causes it to run rich? To me that says it's reduced power for reasons outlined above. I find that hard to believe as replacing the stock system and Cats surely must help :blink:

 

The power result on that curve, with the usual caveats around drivetrain loss calcs and different dynos reading differently etc, also indicates there is a problem - you're about 10% down on what most NAs seem to dyno at, and it's probably because of the overfuelling. It can't be too much as closed loop is compensating OK. I wonder if you reset the ECU, it'd run badly until closed loop relearnt? It's probably pulling out loads of duty. Oh, I don't suppose you can measure injector duty can you? Knowing how many ms they are open for at idle would help a lot.

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The comment re. N/A engines over fuelling when fitted with tubular headers I have seen mentioned a couple of times here on the forum, if the member(s) posting these comments could please comment here it would be helpful.

 

The engine is running on Tesco 99 @ 19o BTDC, stock cams inlet +1o exhaust – 3o, the ECU was reset almost every time I altered the fuel pressure, the engine has an AEM AIT sensor which the stock ECU may not understand, but at light to moderate throttle at legal speeds, the AFR is spot on up to almost 4k rpm, yet WOT @ 3k+ has become WHAT!

 

The ECU was run for 100 miles after final reset before dyno.

 

I have nowhere at home to work on the car or components, and do all of the work on my car and jig engine outside at my friends workshop about 20 miles away.

 

A few years ago whilst on one of my great adventures, I almost lost fingers from both hands with frostbite, and now my tolerance to cold fingers is both poor and painful. As I have mentioned before, I tinker with my Supra for pleasure.

 

To provide the dynograph I promised cost me a day + £50 + fuel, and the weather is too cold to be scratching around outside under the bonnet looking for something to spend money on, that I needn't.

When I can be mostly inside an unheated tin shed a few degrees warmer working on the supercharger components, and be certain that my car will be back together before it gets dark so I can then drive the 20 miles home.

 

By the time the weather and hours of daylight allow me to return to the pleasures of my bi-seasonal mechanic a la naturelle activities, the supercharger conversion will be ready to bolt on.

 

I am disappointed for this projectamuddle conundrum, because I am sure the results would have surprised many, nevertheless, it would have answered many questions.

 

I have been spending so much time in Bob's shed that his wife thinks I have moved in.

 

I really would like to get the car finished then drive to Eastern Europe for some fishing this summer.

Edited by David P (see edit history)
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I can understand not wanting to work on it in the grotty weather :) I do rather get the bit between my teeth when an interesting problem surfaces, hence my sudden barrage of questions and queries. Perhaps it is the AIT, if it was saying the air was much colder than it is then overfuelling would occur. Hard to believe it can measure much colder than it actually is, though ;)

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Tut tut, using none stock sensors with potentially different outputs on a stock ECU surely cant be the way forward :search:

 

Sadly I no longer have the AEM Pro software installed as that included a stock linearisation and you could switch to AEM IAT to compare the difference.

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The AIT sensor change was in readiness for the pending AEM ECU installation, and also tidied up the engine bay and loom.

I didn't want to start dicking the engine bay and loom about retrobackwards for this slightly out of phase upgrade.

 

When we do get a half decent day, I will bodgelock the OE AIT sensor to the loom, hang it in the air box and disconnect the AEM sensor, return the fuel pressure to 43.5psi, zero the cams, zero the ECU and see what happens to the AFR.

 

Which reminds me, I have a brand new AEM 1 bar MAP sensor, but need a 2 bar.

 

Anyone want to swop?

Edited by David P (see edit history)
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I have noze my fruts off today bodgelocking an OE AIT sensor back into the loom, hung the sensor in the air box and disconnected the AEM AIT sensor,(stock) returned the fuel pressure to 43.5psi, (stock) zero'd the cams, (stock) zero'd the ECU, ran it through a full cold start reboot and driven it 25 miles and the AFR now drops to 9.5 @ WHAT!

 

Maybe Japanese logic works backwards :search:

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I have set the ignition timing to 10o BTDC, tweaked the fuel reg to exactly 43.5psi, filled up with the cheap stuff for a change and reset the ECU.

 

I have driven around 100 miles today, and as always, with light to moderate throttle below 4krpm the AFR hovers around 14.7:1

 

WOT @ over 4k rpm the AFR drops to 10.4:1, a slight improvement but still way too rich.

 

Maybe I will just trundle around until the s.c. goes on.

Edited by David P (see edit history)
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  • 2 weeks later...

I have just spotted this in another thread.

 

The lean running on warm start issue will be down to moving the o2 sensor further down the exhaust system with turbo kit on and the exhaust temps are lower which causes the single wire o2 sensors which don't have a heater circuit a while to get to working temp. Causing the car to run lean as when cold they read rich.

Ryan

 

Applying reverse logic to this equasion, my O2 sensors are so 'toastie', maybe it is this that is causing the over fuelling?

 

attachment.php?attachmentid=126444&d=1296936529

js800_insulation_3_001.jpg

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  • 9 months later...

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