After about 3-4K my EVO would regularly drink oil, especially after a couple of hard track sessions I would need about a 1/2 quart. It now has over 24K and I recently installed 272/272 cams, since then it has not used a drop. I was at the track yesterday, after two hard 30 minute sessions I checked the oil and it was completely full. There was also far less contamination than I am used to seeing.

All I can think is that the bigger cams with more overlap have less compression at certain parts of the stroke so there is less blow by? I am not complaining, just curious if anyone else has noticed this?

BTW using the power FC stand alone I dumped in a bunch a fuel at idle (10%) and it has an almost perfect idle. Just a very minor intermitent stumble and never even a hint of stalling. The power FC runs 12 degrees of timming straight from the factory (idles much better than stock ECU with stock cams). Increasing the idle timming beyond 12 degrees did increase vacum but not idle quality. Power on boost >3k is better especially high RPM, here is a dyno comparison with/without cams, at this point I had not tuned for the cams, but it shows the 272/272 cams are not detrimental to the mid range on an EVO. Below 3K there is a slight loss of power but barely enough to be noticable.
If you have engine management then I give 272/272 Without adding fuel the idle was terrible, so if you are running stock ECU the 272/272 is probably not for you.

I have done more tunning since this dyno test and I have just added a Greddy IC and APS intake, seat of the pants says there is a significant power increase. I will post dyno sheets when I get a chance to get down there again. The stock air box with a K&N was fine until the cams went in, on one pull I opened the box and removed the filter. There was a significant power increase at 6K and above, so in comes the APS.

 

Nice numbers!

Do you have the L-Jetro or D-Jetro Power FC?

 

It's the L-jetro, I really have not seen nor to I believe that the D-jetro really buys you more power unless your going with a really big turbo/high boost. Think about it, how restrictive is the MAF assemmbly compared to the air filter sitting in front of it?

Couple of other observations with the cams, I had to jack up the boost controller to make the same boost. I am running a Profec sepc II, I spent most of my dyno time getting the controller set for the cams and playing with cam timming. You can see from the torque curve that the boost does not over shoot and is more stable in general with the cams. The air/fuel ratios did not seem to change much and I did not have time to change ignition timming, although later on street tunning I found that I could run more timing without knock so...

For the cam timming I settled on -3 intake and -4 exhaust. Here is another graph after I got the boost controller set up a little better, this is around 20 PSI tapering to 18. On the street it holds boost much better than on the dyno. The numbers are ok but look how smooth those curves are! This is with zero smoothing!
Oh and this is blowing through a 3" Random high flow cat

 

Nice numbers man!
Have you ever used the Apexi boost controler that works with the Power FC?

 

think dumping in more fuel with an SAFC would keep the idle okay with 272/272 ?

-shahul

 

I saw Eric's car yesterday at MSR and I can't believe how smooth his car idle.

-Off Topic-

BTW Eric, thanks for setting up the MSR day.

 

If you keep the mass air, whats the max boost you can run with an aftermarket turbo setup?? I know the drivability with mass air will be much better.

 

At a certain point it wont be the restrictiveness of the MAF but the limits of the amount of air that it can meter.

 

No, I already had the Profec spec II when I installed the Power FC. After tweaking with it for a while I now have it working extremely well, the trick was installing a .6mm restrictor in the hose going from the manifold to the seloniod. The PFC lets you adjust boost for each RPM point which is nice but I have the Greddy working so well that it is not high on my priority list. Plus the Greddy has certain features that make it very attractive also, like streeing wheel mount boost selector, and a max boost secondary safety.

I don't know? With a stand alone you can add fuel like this at idle without affecting other engine parameters (like timing). Not sure what the stock ECU would do if you tried telling it that you had 10% more air at idle? It might start pulling timing which would degrade the idle quality, or it simply may not allow that much added fuel at idle and throw a code thinking that somthing is wrong? There seem to be plenty of people out there with 272's, AFC's, and data loggers, perhaps some one already knows the answer to these questions?


Hi Pete, you did a little more then just see it This was my first track sessions with the cams, Greddy IC, and APS intake. Pete was helping me monitor engine parameters with the commander as I was literally flinging us around the track chasing down (lapping) a modified M3 (not much of a challenge ). Running 20PSI and pump gas under road race conditions requires a much safer tune than you will ever need for the street, dyno, or 1/4 track, this is what I tune my car for. I need to get one of those cell phone mounts for that commander. I may be doing a water injection system soon.

I am not sure, but we have seen some 500+ WHP dyno charts from people claiming to use nothing but a reflashed stock ECU. There was no mention of a VPC or even an upgraded MAF? so...

Personally I will be happy with mid 300WHP, from my previous experiences once you start to go beyond 50% power increases reliability falls off dramatically. Between engine component and drivetrain, you begin to find all of the weak links with much greater frequency

That point seems to be pretty high and you could theoretically upgrade to a larger MAF. The L-Jetro has full adjustability for alternate MAF's, and some preset selectable MAF curves for certain larger GM MAF's. I do agree that at a certain point it is probably better/easier to just go with a MAP system. IMO that would apply more for a trailer/dyno queen that spends time at the dragstrip. Not a true street/road track car.

 

Look at all the streetcars running MAPs with VPCs.

 

You guys are making me late

I am not saying that switching to a MAP system is neccessarily bad, it just has certain pros and cons like most everything else. On certain other cars the MAF system may be more restrictive or have a more limited range than the one on the EVO. Obviously people have been able to make IMO ridiculously high power levels sucking through the stock MAF system.
So far for the power levels I am looking for (around 350WHP pump gas), I have not seen any improvement with the EVO's running MAP systems. The main benefit I see with the MAP systems is that you can be more creative with your intake system. Although I just installed the APS intake, I am very impressed with the design. Outside of some sort of ram air system (which I believe does help even turbo cars), it doesn't get much better than this.

If your trying to say that simply switching to a MAP system alone on a mildly modfied car is going to give you more power, there does not seem to be evidence to support that, at least with the EVO. If some one does see a significant power increase just by switching to a MAP system, it seems likely that most if not all of the power comes from them running a leaner fuel mixture with say a VPC.

The advantage to the MAF system is far more precise air/fuel control under a wide variety of enviromental conditions. MAP systems guesstimate air flow by looking at pressure, intake temp, and throttle position. As enviromental conditions change the actual airflow volume will change, MAP systems have much harder time trying to predict and compensate for these changes.

I have tunned both MAP and MAF systems and I can tell you that MAF systems are far more consistent over a wide range of enviromental conditions. You set your fuel for a specific air/fuel ratio with an MAF and it keeps it there regardless of conditions, MAP systems,, well you need to keep a close eye on those as conditions change, especially if your running close to the edge.

So if your building a race car where your constantly monitoring A/F ratios and EGT's and can tune on the fly, then MAP systems are ok, but for typical street cars MAF is a much better way to go.
That is why every new production car on the road today uses a MAF system. That especially includes all of the high HP cars you care to mention, Viper, Vette, Porsche, etc.

So if your building race car drag/dyno queen and you want every last bit of power you can get, then go with a MAP system. If you looking for a fast street car for occasional track use, you will be much better off sticking with a MAF system.

 

Silver,

Do you think a flash could make these work or is stand-alone the only way?

 

I am not really familiar with the limitations of a flash, having said that I don't see why not? Accept I don't know if you might run into problems with the emmision control aspects? Dumping that much extra fuel could send up a red flag (CEL) to the ECU, unless the flashes have ways around the emmision control code also?

That would be valuable, I would get my stock ECU flashed just so I could swap it in for emmision testing! Any flashers out there care to comment, PM me if you don't want to talk about tampering with emmision control systems on an open forum.

 

Silver Surfer...off topic, but are you the same person that used to have a RX7??

 

Yes, that's how I became long time friends with Ari and Chris at Rotary Performance (RX7.COM). I had a beautiful, clean, and heavily modified Silver RX7 FD, infact Chris bought it and wants to start tracking it! It's already set up for road racing so.. That car was the original test mule back in 94-95 before they had their own shop car. I even did some drag racing back then, got a trophy somewhere, squeezed and 11.6 out of it. That was a big deal back then, but drag racing just isnt my thing, although I like to know what it's capable of.

I remember your name from the RX7 forum, welcome to the EVO forum. I used this silly call name thinking that I would go easy on the mods and wanted to keep my anenimity incase I needed warranty work Who am I kidding this car will never see the inside of a dealer shop no matter what happens to it. I don't think I could walk in there with a straight face and say 'yea I was just crusing nice and easy down the road and all of a sudden )(*#&' I can't understand why the dealers are being such aholes about warranty work

Anyway back on topic, anyone notice there oil consumption change for the better with the 272 cams?