I just got through tuning my built ls/vtec with Skunk2 2's at 12:1:1 compression.

I'm kind of at a loss b/c they began to fall off off at 7800 rpm! I figured they would produce power at least until 9k or so The cam gears are set at 0ex, -2 intake. The machine shop told me to keep them at least 2 degree's apart to avoid the valves hitting. My tuner wanted to set them at -4ex -2in, but I was afraid the valves would hit, although it made 10lbs more tourque before 3k!

I'm kind of wishing we would have gone ahead an made a run with those settings b/c it may have likely put down some impressive numbers. Would an overlap like that cause the valves to become closer than TDC, and therefore likely make contact? Or rather would it just change the relationship of when they open and close, and that alone?

I'm kind of dissapointed in the numbers 190hp 134 tq. I was expecting to put down around 200 hp. Any ideas or suggestions?

Graph... Sorry for the tiny graph, I'm trying to make it bigger. I'll update soon. Oh, A/F was ~13.0 and pretty straight.



http://www.we-todd-did-racing....D.jpg

 

what is your exhaust setup like...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LSVtecITR &raquo;</TD></TR><TR><TD CLASS="quote">I'm kind of at a loss b/c they began to fall off off at 7800 rpm! I figured they would produce power at least until 9k or so The cam gears are set at 0ex, -2 intake. The machine shop told me to keep them at least 2 degree's apart to avoid the valves hitting. My tuner wanted to set them at -4ex -2in, but I was afraid the valves would hit, although it made 10lbs more tourque before 3k!</TD></TR></TABLE>

I'm relatively sure that the cams make power above that. Did you try leaving the gears at zero/zero for a baseline before you let the tuner retard things? Do you have oversized valves that are likely to strike each other at WOT? Did you clay the valve-to-piston clearance before you bolted everything down?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Would an overlap like that cause the valves to become closer than TDC, and therefore likely make contact? Or rather would it just change the relationship of when they open and close, and that alone?</TD></TR></TABLE>

These are the variables you need to give us. A.) piston dome height, B.) cam(s) lift, C.) cam(s) duration. With these in mind we can more acurately help you figure out the maximum clearance at maximum lift of the intake and exhaust cams.

On a side note, I'm not sure why the tuner determined that -4/-2 was a good setup for anything. Retarding the exhaust cam a little while leaving the intake cam at zero (or advanced) would increase your top end by allowing the exhaust valves's open duration to create a vacuum inside the cylinder as the intake valves open, thus pulling more air into the cylinder. Personally I think you should get the intake vales open earlier and the exhaust valves opened later if you can do so without clearance problems.

Also, 10 ft/lbs more torque under 3k is better than 10 more hp up top as you'll drive at or below 3k in most real situations.

 

im also curious on the exhaust setup. It sounds like youre choking somewhere. Stage 2's should peak much much higher than 7800 rpm unless you retarded youre timing a ton. I made 197hp and 149tq at the hubs with ITR pistons and CTR cams in my ls/vtec.

Also, you mentioned being pretty close to 13:1 a/f ratio all the way around, while thats good while youre in VTEC, you could actually be losing some tq down low. Try to keep it close to 14.7:1 down low and see what happens.

If youre using anything less than a header with a 2.5" collecter and piping to match, this could be your problem. Tb size?

 

Here's the info. .... full 2.5 stainless invida exhaust, everything itr including tb, intake manifold, ect.. jdm 4-1 header, stock valves, motor was clayed , piston dome height 5.7 (valve reliefs cut into piston top, SRP pistions). -4ex, -2in was just the first setting we thought about trying overlap. I didn't know enought about what that meant and was afraid it would bring the valves closer to each other. I have plenty of clearance between valve/piston, so nothing to worry about there (.110in, .120ex with No headgasket, running stock .28 gasket)

I just think there's more power to be made from these cams and unfortunately ran out of dyno money to fully search for it . 14.7 a/f is pretty lean isn't it?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LSVtecITR &raquo;</TD></TR><TR><TD CLASS="quote">Here's the info. .... full 2.5 stainless invida exhaust, everything itr including tb, intake manifold, ect.. jdm 4-1 header, stock valves, motor was clayed , piston dome height 5.7 (valve reliefs cut into piston top, SRP pistions). -4ex, -2in was just the first setting we thought about trying overlap. I didn't know enought about what that meant and was afraid it would bring the valves closer to each other. I have plenty of clearance between valve/piston, so nothing to worry about there (.110in, .120ex with No headgasket, running stock .28 gasket)</TD></TR></TABLE>

I've never heard of anyone with stock valves damaging the head by advancing timing a couple degrees. It's possible that I just haven't been paying enough attention, but the clearances between the OEM valves at max lift is usually enough to get a good sized feeler gauge in there, so I'm sure you could advance/toy with the timing a bit more to pull some top end out of it.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">I just think there's more power to be made from these cams and unfortunately ran out of dyno money to fully search for it . 14.7 a/f is pretty lean isn't it?</TD></TR></TABLE>

14.7 : 1 is pretty normal for under 2000rpm. Yes, if you were pulling that up at 8500rpm you would want to be worried, but if you're at anything lower than about 14 : 1 at idle you should retune your fuel curve a bit. Also, the only thing that brings the valves closer to touching is more lift in the camshaft because the angle of the valves cants them towards each other and more lift will bring the valve faces closer at maximum extention (lift). Regardless of timing, the closest your valves will get to each other (assuming your valve springs are good) is max lift when both are simultaneously open - a rare occurance even with overlap dialed in.

 

hmm intresting.... u kno what my motor is the same
almost the same set up gsr block ported head and ported manifold. ls crank
11.6:1 comp skunk2 stage 2 cams
and anything past 8 there no power it stops pulling. deff feel it but my car its not tuned cams settings is at 0-0
2.5 header 2.5 catless all the way back so i dunno.
when i hit the dyno i'll see what happens

i talked to the guy who owned my motor before me and he said he had the same problem with skunk2 stage 2 in the motor seems to lack top end. he put some crower 402s in and the **** rips up top.
i'll see tho when i get tunned

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LSVtecITR &raquo;</TD></TR><TR><TD CLASS="quote">
I'm kind of dissapointed in the numbers 190hp 134 tq. I was expecting to put down around 200 hp. Any ideas or suggestions? </TD></TR></TABLE>

Kinda seems shitty you didn't reach your goal of 200 HP, huh? Also seems kinda shitty that you bashed Arthur at Trackmasters for being an "inexperienced" tuner. He reached 188 at 12.5 a/f while Jim got 190 at 13.0. I'd rather be safe than sorry if you ask me. Also what everyone doesn't understand is that on the dynojet, without load control, you will typically see .3-.5 a/f richer than on the street, meaning that if you tune for 13.0 on the dyno, you will see 13.3-13.5 on the street. As for the cam gears not having enough clearance while setting them at 0-in 0-ex, that's BS. If that's what your machine shop told you then you should find another machine shop. You can't tell me that you aren't able to stick stock cam gears on skunk2 cams. As for your setup, you still should be happy because you made some decent power on your setup. The problem with everyone is that they read too much on the internet or copy someone else's setup and made that certain amount of power, which in turn should mean that you can make that same exact power. That's wrong. I'm not try to bust your ***** but rather trying to make people think before they start bashing shops or whatever it may be. This can hurt a business. He's had many turbo cars putting down 300 plus horse on stock motor as well as a 520hp b16a. The 520hp guy is also a member of honda-tech and can vouch for Art. Unlike the other Trackmasters in California, Art's a good honest guy who will get things right. He bought and replaced, out of his own pocket, **** that was taken and stolen from the other trackmasters that belonged to his customers here in AL. Arthur is a personal friend of mine and yes he is young but that does not mean he is inexperienced. He obviously must be doing something right if he's young and ownes his own place along with the dyno. Sorry for the long lecture but this is to just let everyone know that there is always two sides to everything whether one or both sides are wrong or right. Hope your setup turns out well.


Modified by Forcefedcivic at 7:01 PM 11/17/2004

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Forcefedcivic &raquo;</TD></TR><TR><TD CLASS="quote"> Also what everyone doesn't understand is that on the dynojet, without load control, you will typically see .3-.5 a/f richer than on the street, meaning that if you tune for 13.0 on the dyno, you will see 13.3-13.5 on the street. </TD></TR></TABLE>

That doesn't make sense. you got it mixed up.

If you see .3-.5 richer on the street...dyno will be 13.5 and street will be 13.0...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DefiantGSR &raquo;</TD></TR><TR><TD CLASS="quote">

That doesn't make sense. you got it mixed up.

If you see .3-.5 richer on the street...dyno will be 13.5 and street will be 13.0...</TD></TR></TABLE>

How does that not make sense? When you are on the dyno it will be richer. When you get on the street it will be leaner. Understand that. Now when you tune on the dyno at 13.0 a/f and then drive on the street, you will see around 13.3-13.5 a/f on the street. Understand.


Modified by Forcefedcivic at 7:27 PM 11/17/2004

 

oh whoops..you're right. read it wrong.

 

no prob

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">You can't tell me that you aren't able to stick stock cam gears on skunk2 cams</TD></TR></TABLE>

well he did say that his CR is 12.1:1. so there might have been some clearance issues thats y his machine shop guy said to run the cmas at those settings

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted k20 &raquo;</TD></TR><TR><TD CLASS="quote">

well he did say that his CR is 12.1:1. so there might have been some clearance issues thats y his machine shop guy said to run the cmas at those settings</TD></TR></TABLE>

well but if he clayed the motor then he should of told his machine shop how much clearance he had so his machine shop could of given him the right settings.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Forcefedcivic &raquo;</TD></TR><TR><TD CLASS="quote">

Kinda seems shitty you didn't reach your goal of 200 HP, huh? Also seems kinda shitty that you bashed Arthur at Trackmasters for being an "inexperienced" tuner.Modified by Forcefedcivic at 7:01 PM 11/17/2004</TD></TR></TABLE>

Ok dude, first of all, the cam gear settings that arthur did on my motor were causing it to barely idle and sometimes not start at all. I also detonated like hell on the way home, so bad, that I thought at the time might be valve rattle. I had spent 5k on a new motor build and the car drove fine down there and drove like **** on the way back. There's no bashing in what I said, just truth.

Arthur IS a nice guy, but seems like he has way too much going on to be tuning cars all the time. He didn't communicate with me much, so I had no idea what he was doing while I was on the dyno, ect. I wasn't trying to bash anyone. I was just telling my experiences with a shop, everyone does that on H/T. I've seen recent posts about "how was your experiece with Modacar.com" ,ect. The reason for these posts is to share your experience with others, not talk ****. I didn't say anything in my post a while back that wasn't the truth. I didn't over exaggerate, or make **** up, I just told everyone what happened.

Actually, you will see a leaner a/f on the street. More air = richer?

Also, Jim at motorvations, not only made more hp, he made more power across the entire RPM range! He also made 10ftlbs of torque. Also, my a/f ratio when I did my base line with arthurs map looked like a damn roller coaster. It varied from 11.7-13.0. It had a huge dip in it from 6k to 7.5k where it dropped to ~11.9. That, along with the low rpm detonation and idle issues, was not tuned if you ask me.

I'm glad Arthur took care of the people who had left stuff at the other trackmasters, however, I left an ecu cover and socketer at his shop. I asked him to ship it to me and he said no prob,ect. A week and a half later, no ecu cover. I called him up and asked him if he had been able to ship it, ect, and he told me he had shipped it. He then agreed to send me another one he had laying around. It has now been almost two weeks and nothing has arrived. I only live two hours away, so you cant tell me the mail takes longer than that. I'm not acusing anyone of anything, but it looks like I'm not going to see an ecu cover any time soon.

I appreciate the good luck I didn't try to copy anyone's setup, I just picked the parts I wanted and went from there. I just think the motor has 200hp potential with more tuning. I was hoping to get some feedback from others who are running the skunk2 cams to see what there numbers were. If 190 is all she's got then cool , I just thought she'd put down a little more. Anyway, sorry for the "essay" post, I just wanted to try to clear up the "bashing" acusations. Good luck to you and Arthur!

 

my motor when i advanced the intake cam 2 degrees it would idle like ****