As of now I am currently hitting this wall around 4k RPMs during acceleration. It gets to about 4K RPMs and it just struggles to keep going, and it seems like once it breaks through this wall from about 4K-5K it will start going again. I'm also running extremely rich, low 10s, at WOT. So this weekend I adjusted my cams and widened my plug gap from .026 to .030.

What I did was, adjusted my cams to 2º ADV EXH & 2º Retard INT and the plugs from .026 to .030, this caused it to run like ****. The car was extremely sluggish. I closed the gap and I put the cams back to similar what they were before to about 3* RETARD EXH & 0* INT and the car ran better. However, still hitting the wall.

I'm going to retard the intake cam to -3* and see how that effects the drive as well as widen the plug gap back to .028. If it gets better, I know I'm heading in the right direction, if that doesn't help, I'm going to advance both cams to about +2*, and see how that effects it.

Does anyone have any ideas about cam timing or has played with it and found some good timings? Or judging by what is happening have any ideas on which way to go? Maybe any other ideas on what would cause this wall during acceleration? I thought maybe the MAF, but I was told that the MAF either works or it doesn't, and I'm not having any MAF problems, so it's working.

What I'm running to provide some more insight: RICA Stage III tune, 19T, Whites, FMIC, Intake, NA Cams, OBX Exhaust, etc etc.

 

Anyone? Cams? Timing?

Advanced both cams to about 3* yesterday and the car ran pretty bad. My vac was real low indicating I had too much overlap. This afternoon I'm going to try 2* RET EXH AND 4* RET INT. I've concluded that my car doesn't like both cams advanced and doesn't like the EXH ADV and INT RET combo. So I'm going to try both of them retarded and see how that goes and see where my vac is at to make sure I'm not getting too much overlap which is also what caused my car to run lean.

I didn't have this kind of problem before with the stock tune, where the car was so picky to the timing, I think it's the Stage III tune that now my car is more picky about where the timing is.

But seriously, anyone have some input that might point me in the right direction?

 

Man, you are going down a path seldom traveled. Most people like the 4 to 6 lane interstate.

Does the ecu control the timing? It may be an ecu issue. I know I'm due some spark plugs and I just took the car to the store and decided to check it above 4k and it was real smooth and strong up to 5,500 where I backed off.

I would contact them about your tune. It should have come with some kind of warranty and they may know what the issue is.

 

Haha, I figured. This is something that has not really been discussed much on this forum. Hopefully it will give some people some insight for those who want to run NA cams or play with the cam timing, and I was just hoping someone may have tinkered with timing and found something that worked for them.

I know the tune adjusts timing. When I was playing with cam timing on my stock ECU, adjusting the timing didn't really affect much on how the car drove, this is the first time I've really started to play with timing on the Stage III RICA tune, and I've come to realize that the Stage III tune is much more picky to cam timing that the stock ecu was.

I did some reading on this site to better understand how the cam works and what happens when you time them and what your looking for:

COMP Cams® - COMP Cams® Valve Timing Tutorial

Because my vac was so horrible and my engine performance suffered when I timed them last, I realized that I had too much overlap, as in, the intake and the exhaust valves were open at the same time too long together, basically, the only way to fix this is by spreading the gap, i.e. advancing the exhaust or retarding the intake.

Today I set the cams to 3* RET EXH (three degrees retarded exhaust cam) and 3* RET INT (three degrees retarded on the intake cam), and I started the car and my vac was roughly 15 in/hg. When you are timing your cams, you want at least 16 in/hg of vac otherwise you know you have to much overlap. So I retarded the intake cam about 1-2 further, this set me at about 4* RET INT. My vac dropped to 16* hg/in and actually when I'm driving and sitting at idle and back off the acceleration, my vac is 20 in/hg, which is excellent. The car also seemed to run smoother. Unfortunately I was unable to push the car at all today because it was 100 degrees here and I wasn't about to go WOT in that kind of heat, nor did I rarely go into boost.

So when it's cooler out I will update this with how it is running.

Hopefully some people find this interesting and will play with this realm of the car. I'm still pretty new to it, but as I've been playing with it, I've started to understand exactly what I'm doing better.

 

I went through the same thing with my Eclipse when I installed FP280's in it. I don't know too much about how Volvo ecu's work, did it retard your timing? The AMS ecu on my Eclipse pulled about 8 degrees of timing when I installed the cams in the factory location. I ended up doing what you did. Adjust them until vac was around 18 to 16g. And no that little car revs to 9k with no problems but suffers on bottom end power.

 

I just did mine this weekend. For some reason I could not go to +2 on the exhaust it would stop at 0. I am at -2 on the intake. I took it for a ride and WOW is all I can say.
I used to hit that same wall on mine at 5200 but now it pulls hard up to atleast 6K. I have not gone past 6K yet.

You were trying lucky's specs on his site?

It did more than just fix my wall issue. It is way smoother overall and seems like it about got rid of the lag between gears as well. When I shift and stomp it in the next gear boost is right there.

In the next couple of weeks I will be doing atleast 1 more car but with stock cams.

 

Yeah, I tried his specs on his new site. I must say I'm pretty pumped to see what Lucky is doing now that he left IPD, that's really cool. Anyways, I tried the cams at 2 ADV EXH and 2 RET INT and it ran so bad. Horrible vac as well. Once it cools down a little bit, I'll see how the current setting works, but it's just too hot to push the car at all, but where the vac is at right now is the best since I've put in the Stage III tune.

Glad to hear yours worked! I can't wait to have a solid power band so I can start playing with boost more and turn it up. Still sitting at about 14psi and I want to be at least around 18-19.


I'm assuming it pulled timing. I'm going to email VIVA Performance and ask what the tune does to timing. But I think I'm getting close to where I need to be, especially with the vac looking better.

 

It pulled a lot of timing. Do you have any general specs of the n/a cams? How much of a difference are they over the turbo ones? One last question. Have you guys ever thought about regrinds?

 

Here are the specs (keep in mind GLT is NA since pre-97s did not have turbos):


GLT
Intake:250dr duration 8,45mm lift
Exhaust:252,6dr duration 8,45mm lift

T5
Intake:242dr duration 7,95 lift
Exhaust:243,5dr duration 7,95 lift"

I think people have thought about re-grinds, but using the NA cam is an easy alternative, and there still is not a lot of people playing with NA cams that are actually playing with timing and what not. No one has dyoned them for before and after results either.

 

Have you gotten anywhere with it yet?

 

Yup. I finally had a chance to get some WOT runs in yesterday. The wall is pretty much gone. It may slow down a bit during that range, but nothing like it was before. I'm going to advance the EXH cam a degree or two to see if widening that gap between the two cam degrees will get better results, but nonetheless, I think I found the sweet spot. So once that's done, I'll be at 2* EXH RET and 4* INT RET. We'll see how that goes.

 

I think I'm getting closer. Have the cams currently to 2* RET EXH and 4* RET INT. The wall is getting smaller and smaller. First gear especially felt way better. Today I'm going to set them to 0* EXH and 2* or 3* RET INT. I'm trying to get the cams out of being retarded so much and more central on the timing range. We'll see how it feels.

My cam timing log. lol

 

"meh"? LOL looks like something I would write. Are you running N/A cams?

 

lol. Yeah, I really had no other way to describe how it felt, because, it was just, meh. haha.

And yes, NA cams, which is why I can't use stock cam timing and it's being so picky.

 

Ohhhh, I think I'm getting close with the timing. At first the vac was a little low and it was running lean at idle, but after a block the vac was down to about 17 in/hg in idle at it was idling where it should be 14.7-15.3. And the good part, got to an on ramp floored it, chirped tires from 2nd to 3rd. I know, some guys do that no problem, however, this is like only 10 psi yet and my boost does not come on until about 3k RPMs. Another on ramp, chirped 1st to 2nd without trying, and then 2nd to 3rd AGAIN. I was so pumped, I'm getting there.

 

I am retarded on this thread. It also looks to me that you way too retarded. About overlap -- you need some, in order to the benefit of the top-end. You might be on the low end of that balance. Turbo just makes this even more pronounced.

What did Viva say? Since you have too many variables (e.g. NA cams, manual transm, etc), it may take you a little longer to get it right. Keep it up dude...

Advance info, vac are helpful. But, if you have a way to dyno it, it might be more helpful.

 

One more thing -- take it easy at this phase. This is when many people blow holes in their blocks..

 

Well, with the NA cams, when you put them on a turbo engine, you usually don't have an even balance of power with then, you either benefit top end or bottom end. I'm trying to get my bottom end power from the NA cams so my top end can be taken care of by the turbo.

I didn't email VIVA yet because I'm getting close to where I need to be I think. I'm going to advance each cam one degree tomorrow, this would put me 0* EXH and 2* RET INT.

I know I need some overlap, but the overlap I was getting before was getting me around 10 in/hg of vac and horrible engine performance, and when this happens, you basically need to widen the gap on the cams by advancing the exhaust or retarding the intake (I guess based on what you're timing currently is). Hopefully I can get where I am with the timing then I can start turning up the boost.

 

Overlap gives you subpar idle to begin with; add the retardation, it makes it worse, hence vacuum at 10. You may have to live with a subpar idle, maybe at 13-14 after-all, but some advance might help.

It's possible that Viva tuned conservatively, which is what they should have done, given your variables.

Any dyno numbers soon?

 

I'm not going to deal with subpar idle, especially with vac at 13-14, for multiple reasons. One, vac that low causes the engine to run extremely lean at WOT, in the mid 13s, that is NOT ok. Two, it causes horrible engine performance. Three, why would I deal with a horrible idle and poor vac/AFR numbers when I already have the cams dialed in where my idle is 17 in/hg and I have great AFRs and the engine performance is great?

I think you missed the part where I said I'm starting to get my cams dialed in and the numbers are looking good, to have a poor idle of 13-14 in/hg would mean I would have to go backwards.