Help needed 264in/256ex 11:2 cr engine, hesitation.

[34atm85]

Hi to everyone, I am new to the forum (4 months) I mostly search and read rarely post. This time I need help.

I build an engine with 264in/256ex, 11.2:1 Cr. 4AGZE Crank and rods, wiseco forged pistons, acl bearings, arp bolts, complete head build with HKS springs. KN&N filter, magnecore plugwires. no check engine lights.

I feel that car is not fast, with Wide band I see 12.5 at idle, 14.8 - 15.4 at cruising, at wot from 12.4 - 12.8 (plays up and down), I found that some people says the best is 12.8 - 13.2 (I am not sure if it is wise with 11:2 CR)

I have this annoying t-vis rattling sound just started after the engine build. Car is not revving aggressively, I feel that it is slower than a 16V golf GTI
1.8. I can rev to 7250 rpm but it is sloooow.

So I need you help. What is the best AFR to get most from engine at mid - WOT.

Is there a special setting on cam gears, I've seen +3i n - 4ex, but I am not sure if it suits to HKS 264in/256ex. I found this but didn't find anything different than I made. http://www.imoc.co.uk/forums/viewtopic. ... 605b6eeeb7


Is there a way that I can fix that t-vis sound or is it something that happens after some time. I found some links (http://www.imoc.co.uk/forums/viewtopic. ... ght=vacuum) that he shows how he renewed it but I want to fix mine instead of getting something which may have the same problem.

So I desperately need your help.

Thanks in advance

[aw11rally]

TVIS can start to cause problems with non-standard cams. If I was you I would ditch the TVIS and port the head to improve breathing.

Have you looked at the ignition and cam timing?

(I presume you are using high octane fuel? need 99octane with 11.2:1 CR, and some extra advance may improve matters)

[34atm85]

TVIS can start to cause problems with non-standard cams. If I was you I would ditch the TVIS and port the head to improve breathing.

Have you looked at the ignition and cam timing?

(I presume you are using high octane fuel? need 99octane with 11.2:1 CR, and some extra advance may improve matters)

Thanks for the reply, I am using 97 octane fuel. I removed it but car was very powerless up to 4500 RPM, so put it back. Does this happen to everyone use cams which are non standard. I set the ignition 10 according to the book while it was in diagnostic mode. No engine knock at high revs but I feel that car is not revving freely or I am waiting too much from this engine.

[Sparky_2day]

I done away with the T-VIS system on my 4AGTE, i had the face of the inlet manifold built up and machined flat agin so that it mated straight onto the head. i didnt want it in the way for running high boost etc.

when i was running in my engine we made the ignition map very safe so as not to risk any pre-ignition or anything. One problem i had at one point was that the ignition was retarded too much so that cylinder pressures were too low and the engine hesitated very badly even under slight load.
advancing the ignition back sorted this. I am running an AEM ECU so ignition timing was easy to check / change.

Ignition timing would be a good place to start.

I think AFR 14.7 is Lambda 1, anything less is heading towards running rich. mine runs generally in the 12-13 area but my car has not been mapped fully on the rolling road yet.

[aw11rally]

From what I remember from our last chat you are used to a lot more power arn't you?

Any N/A tuning to the 4AGE is going to move the power band even further up the rev range.

Our rally car is putting out 137bhp at the wheels and has next to nothing below 4000rpm, from then on it really starts to pick up and will keep pulling well off the rev counter!

Maybe you are expecting too much low down, this is not a torquey motor, it needs revs revs and more revs.

[34atm85]

From what I remember from our last chat you are used to a lot more power arn't you?

Any N/A tuning to the 4AGE is going to move the power band even further up the rev range.

Our rally car is putting out 137bhp at the wheels and has next to nothing below 4000rpm, from then on it really starts to pick up and will keep pulling well off the rev counter!

Maybe you are expecting too much low down, this is not a torquey motor, it needs revs revs and more revs.

Yes mate, I used to a lot of power but the problem is low down is acceptable but high rpms are missing. revving is too slow. I dont feel any kick but only loud air sucking noise. I am thinking why I did not buy your ITB and omex because car still consumes a lot when revved high rpms.

[34atm85]

I done away with the T-VIS system on my 4AGTE, i had the face of the inlet manifold built up and machined flat agin so that it mated straight onto the head. i didnt want it in the way for running high boost etc.

when i was running in my engine we made the ignition map very safe so as not to risk any pre-ignition or anything. One problem i had at one point was that the ignition was retarded too much so that cylinder pressures were too low and the engine hesitated very badly even under slight load.
advancing the ignition back sorted this. I am running an AEM ECU so ignition timing was easy to check / change.

Ignition timing would be a good place to start.

I think AFR 14.7 is Lambda 1, anything less is heading towards running rich. mine runs generally in the 12-13 area but my car has not been mapped fully on the rolling road yet.

thanks for your reply, with turbo setup you are right but with NA it was too bad without tvis. it even didnt chirp the wheels. I think turbo afr must be around 11.3 and safe side is 10.8 to 10.5 (you may loose some power but it is safe) at wot. I do have a gto which is 600 bhp and running on 22 psi boost, if I go leaner than 11.3 than it starts pinging and egts go high.
The question is what it must be for a NA car, what I found is corolla users with carbs are targetting for 12.5 to 13.2 but I am curious how come a 9.4 cr standard cam car needs the same amount of fuel with 11 cr and 264 8.1 lift cams.

I am totally stuck

[vashy]

Hi 34atm85,

What cam timing are you running now?

With my setup, I am still running the stock cam gears but I have an exhaust cam on the intake and I now think this affects the cam timing. I looked at the HKS cam cards for the exhaust and intake cams and I think my intake cam timing is retarded quite a lot from the stock setting. I think this is what gives me the high peak torque of 6600rpm, as you can see on the graph, in the thread you linked. It is quite significant and I can feel it when I drive. (obviously the torque and power figures are wrong but I think the curves are useful)

If it helps, I can dig out the cam cards and figure out the exact timing. When I worked it out before it was quite a lot, perhaps 6 degrees. So, I would recommend, double check your cam degreeing, then set maybe 5 or 6 degrees retard on the intake, and stock timing on the exhaust. Then it will rev (:

[34atm85]

Hi 34atm85,

What cam timing are you running now?

With my setup, I am still running the stock cam gears but I have an exhaust cam on the intake and I now think this affects the cam timing. I looked at the HKS cam cards for the exhaust and intake cams and I think my intake cam timing is retarded quite a lot from the stock setting. I think this is what gives me the high peak torque of 6600rpm, as you can see on the graph, in the thread you linked. It is quite significant and I can feel it when I drive. (obviously the torque and power figures are wrong but I think the curves are useful)

If it helps, I can dig out the cam cards and figure out the exact timing. When I worked it out before it was quite a lot, perhaps 6 degrees. So, I would recommend, double check your cam degreeing, then set maybe 5 or 6 degrees retard on the intake, and stock timing on the exhaust. Then it will rev (:

Hi Vashy,

I gave the camcard I found to the mechanic and he made the timing. What I know is that I have the 264 on the intake side and the 256 on the exhaust side. So do you suggest switching them or is it OK if I keep it like this. On the other side I have the gears on both cams so I am able to use both of them whereever I want. Your thread was very helpfull and I read it so many times to understand completely. Do you think the ecu is capable of providing enough fuel at wot and do you think my CR is to high for the timing already set in the ecu. I am trying to find the hidden maps that was talked about in your thrread but not successful until now. If you can find and send me the cam cards it will be very helpfull and I will be thankfull to you. The base timing is 10 degrees with diagnostic mode on. When I remove it it is around 15 - 16. I will check the tps because I did not check it yet. The idle is not smooth and the afr is around 12.5 sometimes it goes up to 13.2 and I wil that car is shaking like valve setting are not correct. when I push the gas pedal I feel that the car is not responding happily, if I rev it around 3000 - 3500 to the limit it is acceptablebut from 1000 rpm you can feel the hesitation easily. By theway I also lightened the fly wheel around a kg, lightened the rods (not to much), pistons are already light and the crank, flywheel and clutch balanced all together. All rods are within 1 gram difference. All pistons are the same weight. so I am still thinking what is wrong with it.

So in order check my understanding, you said that you installed the cams with standard cam gears. The timing is the same with standard cams (or not) and after setting it you dialled exhaust cam stock timing and intake 5 degrees retarded.

How powerful is your car, is it as good as a modded pug 106 (around 140 hp), mine is not


Thank you very much to everyone responded

Hope I can find the answer.

[cartledge_uk]

Sorry but with your compression ratio the cam timing should be used as a guide, and you really need to get them set up on a dyno. You may then find the 'power' you are after.

And also dont think you can just throw in pistons/cams etc and beat a 106/golf gti. The 106 (and early golf gti) is considerably lighter than the AW11, and the golf has more power than the MR2 mk1 std. And to be honest it would be hard (and very very expensive) to beat a 106/golf.

If you're looking for 'figures' and 'beating' power figures of other cars. you got the wrong car with the MR2 mk1.

[34atm85]

Sorry but with your compression ratio the cam timing should be used as a guide, and you really need to get them set up on a dyno. You may then find the 'power' you are after.

And also dont think you can just throw in pistons/cams etc and beat a 106/golf gti. The 106 (and early golf gti) is considerably lighter than the AW11, and the golf has more power than the MR2 mk1 std. And to be honest it would be hard (and very very expensive) to beat a 106/golf.

If you're looking for 'figures' and 'beating' power figures of other cars. you got the wrong car with the MR2 mk1.

Mate, the reason the reason I upgraded the CR, balanced the engine and used cams is to have a decent engine revving healthy and give me fun as a daily driver. I am not racing any cars in the traffic, I am living out side of the city and I have a beautiful road with curves passing through a forest. There are no radars or police waiting me there. Not too much cars around. My joy is sliding the car and feeling that adrenalin. I know this is a 1.6 liter high revving engine but problem is mine is not revving that good. I think 0-100 of a standard mr2 is around 8.1 secs. (less than a golf gti 9.0 secs) and I know it is heavier than a golf and plus me (100kg) it is worse but I am sure you can understand a healthy revving engine vs hesitating one. I used to have a golf gti 1.8 16V, audi coupe 2.0 8V, Fiat tipo 2.0 16V, Mondeo 2.0 16V, Nissan Primera GT 2.0, Lancia Thema 2.0 8v, and I still have a subaru forester sturbo, a Nissan micra 1.5DCI and a Mitsubishi 3000GT but I fell in love with this small thing this is why I spent a lot of moneyand why I am so disappointed. Any way I will listen to Vashy and check my timings again with the mechanic, may be he did something wrong and I am losing power due to advanced intake cam. Hope my mechanic did it wrong.

Thank you very much for your reply.

[vashy]

Hi, I have to be quick; I will try to answer more of your questions tonight, but...

I have the gears on both cams so I am able to use both of them whereever I want.

If they both have gears then they are both exhaust cams, this is fine, but you need to use the numbers from the exhaust cam card for degreeing both cams.

I've had another thought, I think generally when tuning engines, if you increase the CR then you don't need so much ignition advance. Also the stock 4AGE has fairly mild compression for an NA engine and lots of ignition advance, even with lots of throttle/rpm. So I suggest, try it, back off the ignition timing by several degrees (less advance) and go for a drive and see if this makes it better or worse.

[34atm85]

Hi, I have to be quick; I will try to answer more of your questions tonight, but...

I have the gears on both cams so I am able to use both of them whereever I want.

If they both have gears then they are both exhaust cams, this is fine, but you need to use the numbers from the exhaust cam card for degreeing both cams.

I've had another thought, I think generally when tuning engines, if you increase the CR then you don't need so much ignition advance. Also the stock 4AGE has fairly mild compression for an NA engine and lots of ignition advance, even with lots of throttle/rpm. So I suggest, try it, back off the ignition timing by several degrees (less advance) and go for a drive and see if this makes it better or worse.

I talked to my mechanic and I will visit him this afternoon to check the timing, you are totally right I think he used the intake setting for 264 instead exhaust.

Thank you very much

[cartledge_uk]

You appear to have missed my comment.

With your engine mods you really need to set the cam timing on a dyno. The hks figures are guide figures. The timing of your engine will be different to that of vashy's or any other because of your other mods.

[34atm85]

You appear to have missed my comment.

With your engine mods you really need to set the cam timing on a dyno. The hks figures are guide figures. The timing of your engine will be different to that of vashy's or any other because of your other mods.

I totally understand what you are saying and I will do in on the dyno but today I did something

I took my car to mechanic and asked him to change the cam gear setting. I didnt understand what he did but what I have seen was

the obx Cam gear on the exhaust side was set to -10 while the timing point was lining with the point on the cam cover. On the intake side it was at +3. So I decided to take my chance and asked him to change the exhaust to -5 instead of -10. He told me that I was advancing the exhaust 10 degrees, I said yes do it. I drove the car it was pinging and retarded from distributer but because I dont have a advance light I just made it according to the line I made on the distributor according to the old setup. so I drove the car --- YES it is far more better, idle is smooth and car is more andmore aggressive.

Tomorrow I will go to dyno What I feel is after some harddriving I hear some pinging at low to high revs not at high revs though.

[vashy]

Do you think the ecu is capable of providing enough fuel at wot and do you think my CR is to high for the timing already set in the ecu.

I think fuel should be okay. When I went to the dyno, at somewhere around 6000rpm, I saw a co2 of 4.2, which converts to an AFR of around 12.93. It's very interesting to see your AFR wideband numbers!

I do think that with a higher compression ratio you need less spark advance. I think it's because a denser mix burns faster. So, you can't just set the timing to 10degBTDC, you must find the advance that gives you most power and no detonation yourself.

As you know, changing the exhaust cam timing affects the ignition timing, because the distributor is driven off the gear on the exhaust cam.

But also, changing the cam timing will change the amount of air you get into the cylinders, so your air density will again be different (I think it's called dynamic compression ratio). And this will change what ignition advance you need too!

So you must be careful to listen for det after every change you make!

It might even be best to set the ignition timing very safe, with not much advance, while you are setting cam timing, and then gradually advance it once you have the cams set well.

I hope the dyno goes well!

[34atm85]

I hope the dyno goes well!

Thank you very much, so I talked to my mechanic again after making some calculations I got what he did. He made the timing according to the camcard but instead of turning the exhaust cam to the left he just used the screws on the adjustable gear and set it like that. So when I checked the timing I thought he retarded the timing almost one teeth (10 percent on cam) so today I checked the OBX cam gears which timing points are 1 point different than the original cam gears I realized that I advanced the exhust timing 10 degrees and the intake was already advanced 6 degrees, so what I am going to do is, I will change the exhaust back as you said (to original timing) and change the intake one -6 or -5 degrees. yesterday car was very responsive but today after harddriving I felt that I lost the power and started pinging sometimes so I retarded from the distributor and will check tomorrow after I make all changes. In the mean time I will install and EGT and already installed an AFR, if you want I can log and send you the afr numbers after the setup.

Is there any chance you may have the hidden map jumper settings, I will try to richen up high rpms with that maps with lower ignition if possible and will see how it works with 11.3 cr

Again thank you very much for your help now I am getting happier

[vashy]

I'm glad you are finding better results!

pm JMR_AW11 with your ECU part number, and ask him about the secret map mod. Tell him you have a wideband AFR meter; I think he will be interested in the results. The technique is different with the different ECUs, but if your ECU number is the same as mine (ends in 17070) then I can tell you the procedure.

[vashy]

You should degree your cams (find TDC, find peak lobe point, mark the two points on a degree wheel, move the cam gears such that this angle is the same as on the cam card. Then mark this point on your cam gears, this is your base cam timing). Then it doesn't matter about using the exhaust cam on the intake, or whatever, just use the intake cam card numbers for the intake and exhaust cam card for the exhaust, whichever cams you are using.

However, if you are looking at the stock cam gears to get your base cam timing, I have wrote a post in my earlier thread which might help (and should help clarify my earlier posts)

By the way, I am interested to know if pinging/det shows up on an EGT gauge with this engine; if you put one on, let us know!

[34atm85]

I'm glad you are finding better results!

pm JMR_AW11 with your ECU part number, and ask him about the secret map mod. Tell him you have a wideband AFR meter; I think he will be interested in the results. The technique is different with the different ECUs, but if your ECU number is the same as mine (ends in 17070) then I can tell you the procedure.

I am glad I am in this forum I will send it to Jeremy, he already sent me a PM to get my ECU number. I will definitely log down the EGT and Wideband numbers and will let you know. The Base timing is correct, my mechanic told me whats happening at the moment. He said because I advanced the exhoust cam, the valves open earlier and due to that there is more compression at the beginning but I am losing power because exhaust is opening earlier. He said we need to retard the intake and keep exhaust at the place where you also said, 0 advance or retard. He also told me that because the intake was advanced the valves were opening earlier which means due to the overlap some of the air was already going out before the exhaust was closing. So now I totally understand what you are saying I was not able to touch the car at weekend because my mum had a traffic accident. She is totally fine but the car is a bit damaged. I was dealing with it.

I will post the results ASAP.

Thank you very much again.