4AGE budget cam install and tuning

[34atm85]

good discussion guys

It sounds like ITBs on the stock ECU really isn't going to work.


so... we will see what happens...

Vashy, take this as a promise, I found a document which a guy prepared was about cam timings and results, like in+3 ex +6 etc, he checked almost every setting and provided details about the result. I lost the link but I am trying to find it, if I find it I promise to share

Due to the limitation of the ECU, you will not be utilizing the cams because they are going to lift the power band to a higher RPM. I totally understand you and to tell you the truth the problem of our cams is, thie lift is low, so we are not going to get enough torque to feel what we are looking for. Cam helps you to rev due to degrees but lift of the cams create the torque to move the car with more G.

I wish I bought at least 9.xx lift cams and a piggy pack to support them.

[vashy]

would be great if you could find it (:

I know what you mean, changing the cam timing allows us to move the peak torque up and down the power band, but there isn't that much torque there to move around! On the dyno print I have barely 100lb/ft peak, at the flywheel. The 4AGE isn't renowned for its torque haha!

[vashy]

cam timing

time for an update!

I took my stock cam gears off and fitted some shiny adjustable ones.

After installing the cam gears, initially set to zero, the car drove slightly differently. Slightly rougher idle, maybe a touch more low end torque. So I suspect zero on my adjustable gears is slightly different to the stock cam gears.

To find out how much, you can find exact TDC and zero the cam gears. However I used the slightly less scientific method of finding out how much my ignition timing was out, and what exhaust cam adjustment was needed to get it back in again. Using this method I think my cam gears give about +1deg advance when set to zero. I'll figure it out exactly at some point and edit the results to give accurate numbers.

So now I tried some settings. The first few settings I tried were just with the car stationary, checking how it revved and idled, so I could quickly try lots of different settings and get a feeling for what different cam timings do. The results were really not what I expected...

I left the exhaust cam at close to zero and tried adjusting the intake cam first.

intake
5deg advance
really lopey idle. sounded awesome, but getting it to idle happily at <1200rpm would be tricky! ran alright once it had some revs.

5deg retard
very nice idle. revs good, throttle response good.

10deg retard
still nice idle, maybe even nicer! still good revs and response.

My cam gears maxed out at 12 degrees, so I set them back to 10 and moved on to the exhaust cam. Also I should add that I was a little confused at this point, because my results were the opposite of what I was expecting! Also I double checked my cam timing and it's correct; I'm not a tooth out.

exhaust
After each exhaust cam adjustment I reset the ignition timing to 10degBTDC each time.

5deg advance
idle a bit rougher, felt boggy and revved up kinda slow when I blipped the throttle.

5deg retard
idled nice, revved up quick again. I could get it to idle at ~800rpm to set the ignition timing, which is normally quite tricky.

I couldn't try any more, because I was running out of adjustment on the dizzy.

So, I left it like that. I have a super sweet idle, low rpm driving is fine, and the power comes in 6000-8000rpm, and there's more power than before. In fact I have to watch the tacho because it really doesn't drop off at all! So I'm running intake -10, exhaust -5, which with my cam gears zeroed I think is probably -9,-4. I think I might back off the intake retard a bit at some point, but I'll probably just drive it round like this for a while.

[cartledge_uk]

Top post

You can always pull the dizzy out and move it round a tooth, this was my issue. I couldnt get the blasted thing to idle at all and I was getting bored of setting the timing, pulling the veniers off, fitting the std ones, checking timing etc.

In the end it was the 'recomended timing' of my cams meant that I had to actully set the timing with the dizzy cog not in the correct possition, runs fine now.

(engine 4agze with HKS 256 cams [and some other mods] )

[vashy]

Thanks! in fact I think it calls for a twisted smiley!

I had plenty of adjustment on my dizzy, more than 5 degrees either way.

idle vacuum (getting techy now!)

I had a vacuum gauge connected while I was tuning. I was seeing less vacuum when I had the intake cam advanced and the lopey idle. I think around 300mmHg, it was normally more like 400. Less vacuum would make the ECU think the throttle was open more and probably meant it was running rich. With a mappable ECU you could run cam timings with more reversion/overlap and just reajust the idle/low speed fuelling. I wasn't expecting lots of retard to work well with the stock ECU but it seems to!

[vashy]

my current favourite cam timing: in -3 ex -5

This give me a load more low end from about 2.5krpm, I suspect because of the overlap, and the top end is still really good (although not quite as much as when I had the crazy retard). The low end drivability is affected though; I can't really run much more overlap than this, on the stock ECU. Getting the cam timing has made almost as much difference again as the cams did originally, I really should get it dyno'd again!

[vashy]

the tuning continues!!

when running aggressive cam timings (with 2 or more degrees of extra overlap) I am getting rough running at low rpms (1-2k). you can't cruise at these very low rpms because it jerks, and the idle adjust screw is no longer enough to sort out the rich fuelling at low rpms/idle.

All this is caused, I believe, by the overlap/reversion killing the manifold vacuum and consequently throwing out the MAP sensor signal. This throws the ECUs map onto the wrong cells, as if you have the throttle open more than you really do.

So, as a bit of an experiment, I aquired one of these.



It's a bit of a bu88er to install because the ECU is so far away from the dash. However, this isn't as bad as it seems, because it is so JDM tyte yo and has flashy lights.

It's an original SAFC. It lets you adjust the MAP (or AFM) sensor signal at 5 different rpms. It calculates interpolated adjustments as you rev between the rpm points, so it's pretty nice. The later SAFC I and II have a screen and can adjust according to throttle position as well, which can be quite useful. For my tuning, where it can run on the stock ECU anyway, this SAFC and the idle adjust screw is enough.

tuning the SAFC

I went to a closed road at night and tuned the knobs. I found I could tune the first two knobs (800rpm and 2400rpm)pretty well by feel. Turning the knob down stopped the jerks, and transitioning between off and on throttle became much smoother too. Turning it down too much results in a very subtle stumble, which I suspect might be starting to run lean. I also turned the knob up for 7200rpm - the stock map is backing things off by this point but my cams are really on it here.

You can see the positions I have ended up with in the picture. 800: -25%, 2400: -15% and I put +20% on the 7200 knob. I can get this fine tuned on a dyno.

The results.
Very low rpm drivability is much improved and there's loads of low end now, which is really useful and fun when driving round town. In fact from 2k the thing goes like a raped ape, all the way to 8. There's extra power at 5000 and it doesn't drop off at all. That's how a 4AGE should run

[Lauren]

Very interesting John!

I'm on the dyno on 15th October, will be interesting to see the results.

[pk_090]

This is an awesome thread Really good read as i have a set of TRD cams (which ive been told by Lauren are hKS built.) Im not sure of duration on them but i know they have came off a mk1 race car. I was reading that when you cam it, you should disengage and remove t-vis, is this a must? and also whats the gizmo you have bought, would i be able to run these cams of a megasquirt ECU so i can run throttlebodies?

[Lauren]

Alex,

What are the duration of your cams? It will be clearly stamped on them. You must find this out as it's critical.

Theoretically it would be better to keep the TVIS though mine is disconnected with no ill effects it seems. So in that respect it's up to you. Just try it with and without, easy enough to do.

No idea about megasquirt, sorry, it's not something I would consider using.

You will need a standalone ECU to run the throttle bodies. Look on the AE86 forums, lots of info there.

[cartledge_uk]

This is an awesome thread Really good read as i have a set of TRD cams (which ive been told by Lauren are hKS built.) Im not sure of duration on them but i know they have came off a mk1 race car. I was reading that when you cam it, you should disengage and remove t-vis, is this a must? and also whats the gizmo you have bought, would i be able to run these cams of a megasquirt ECU so i can run throttlebodies?

As Lauren states duration is everything. 256's will run on std pretty much, 264's you maybe able to get away with near std.

If you do disingage TVIS, it maybe worth gutting it, but if you dial the cams for top end, the TVIS will help with the bottom end.

AS for megasquirt, if you can wire it, then yes it will run it.

[elbon50]

Please tell us more about the SAFC Vashy

Peter

[vashy]

I'm on the dyno on 15th October, will be interesting to see the results

will be very interesting hopefully they can do an AFR trace.

Please tell us more about the SAFC Vashy

sure, post up what you need to know.

[elbon50]

Please tell us more about the SAFC Vashy

sure, post up what you need to know.

If I understand correctly its an APEXI Super Air Fuel Controller Vashy. Allows readout & adjustment from the drivers seat

Never seen or heard of them before so know nothing about them

However I have a set of HKS 264 cams, which I will be fitting later and also a Megasquirt MS2 ECU which I have not yet got working properly. Am interested in any aids to tuning

Peter

[Lauren]

Okay been on the rollers at TDI North:

132bhp. Peak same on both ECU's. This with HKS 264's, 4-1 manifold and system and an AE92 bottom end.

The modified ECU was massively over-fueling, so in this case stock was better!

[tottacrolla]

Lauren when you say bhp I guess that is power at the wheels ?

[Lauren]

That'd never be power at the wheels would it?

It's at the fly, will get a graph etc by email which I'll post up.

Was much more concerned with looking at the fueling than the other details tbh.

[JMR_AW11]

It's definitely worth addressing the overfuelling.

A few years ago I had my stock mk1b remapped by Rich Benton at Powerstation Tewkesbury and he removed the stock overfuelling whilst remapping the fuelling and it does help hold onto power past the peak. My car delivered a fatter torque curve and produced smoother power at high rpm.

After mapping I'm not sure the car was realistically any faster but it was the sweetest 4AGE engine I'd ever driven when being driven hard although it was a fairly good one anyway.

[tottacrolla]

It could be at the wheels given your engine spec. Lauren:

http://www.aeu86.org/viewtopic/tuned-4a ... ge+results

[SuperRedMR2]

Id think that'd be at the wheels, as mine is putting out 130.6 with standard cams at the fly.