Local

Hello HT,

Looking for some ideas & opinions on what may have happened with my build. Recently added a couple things which i believed would have increased my output even a little. I ended up losing ~ 3hp/3tq & all throughout the power band. I replaced the IM + intake, removed cat & added a few upgrades.. see below.

Old set up/ dyno:

GSR block
81.5 usdm itr pistons ~11:1 comp
Pro 1's
Performer X IM
RMF narrow w/ 2.5 cat
Short ram



Changes since last dyno:

3" cai
Straight pipe
Sk2 pro IM
RDX injectors, fpr & 255 pump
Sk2 alpha header
Portflow standard headwork
Spring style LMA's



Same dyno, different days months apart. Vtec set to 6700 on both tunes, sprokets adjusted but not changed between 1st & 2nd tune. I swapped manifolds due to a casting flaw in the Performer X which was leaking coolant. Tuner advised that may have been the cause & also pointed finger at the pro1's, stating possibly the wrong choice of cam. Ideas & opinions welcome, going back to the drawing board with this one.

Thanks,

B_Swapped93

IMO 11:1 comp is to low for pro's you'r tuner is right you'd see better gains with T2 or T3's the im swap shouldn't do that to you even tho the performer x is better for top end.

98vtec

stop looking at the numbers and look at the graph.

what is different about them?

B_Swapped93

^Perfomer X beats the skunk up top no dought(maybe over all even). Im just suggesting that he needs higher comp to truly benefit from those cams. adjustible cam gears wouldn't hurn either imo.

Local

i notice the huge dip right after 4k, whereas no dip before.

the cams were degreed in last tune, he didnt feel there would be a benefit from messing with them again.

B_Swapped93

where's you'r VTEC crossover set ?

Local

6700, same as 1st tune. tried adjusting that too to no avail

DazeMS

the skunk 2 IM sucks.. plain and simple.. Your vtec crossover on the 2nd graph needs tp be at 4600-4800 rpm.. THe skunk2 IM is just like a b16, you were better off with the performer x. You should be making more power on 11-1 comp over my setup, but your not. YOu either need a better tuner or you have compression issues.

EDIT:: What exhaust are you running?
EDIT EDIT:: And the vtec cross should have been at 5-5300 rpm on the first graph..

DazeMS

https://sphotos-b.xx.fbcdn.net/hphot...96888008_n.jpg
mods

AEM CAI
68mm Omni power TB
Skunk2 pro IM
Edelbrock 4730 camshafts
Skunk Pro cam gears
jdm ITR 4-1 knock off 2.5'' collector
Magnaflow highflow cat 2.5''
2.25'' ID ( 60mm OD) yonaka n1 style exhuast
Very similar setup vtec set at 4800.. stock is 5300 which is why you see the performer go up then down at the 5k range as your vtec cross should be hitting then , not later.

slowsleeper

Your tune looks fine, ignore the guy's suggestion about where VTEC should be at, has no idea what he's talking about.

You lost power, throughout the rpm from before because:

1. Gained port volume from headwork
2. Shorter runner IM

That as well as the compression on the "lower" side of the spectrum. As you (or some members) can see, the Pro series cams have pretty good primaries. Even in your first graph (stock port?), with the longer runner Performer X IM, VTEC was already high up in the rpm (6700).

When you gained port volume through the portflow headwork and went with a shorter runner IM, you lost that torque/power down low. In order to make up that power with the ported head, you need RPMs. IMO Pro1s are not the cam to carry power into the higher RPMs and thats why it peaked where it did.

shoot me a pm if you'd like more insight on it

Oh yeah, that hump in your second graph is just the intake resonance (don't let the noobs tell you that VTEC should be set there lol).

DazeMS

yea.. cause gaining over 10 ftlbs and 10hp from changing JUST the vtec cross over from 5300(stock) to 4800 is sooo not worth it. I am only running a similar setup making way more torque over a longer stretch with "less aggressive" cams. I have NO IDEA what I am saying when I provide a graph to support it.. The BUMP is because of resonate behaviors due to the skunk.. by only running on the primary, you are NOT taking full advantage of the resonate response.. aka , the primary cam lobe is not matching its frequency past its peak.. the high lobe needs to take over from there, you arent taking advantage of the high lobe ( vtec) and what its function is designed for. oh well, I will take my No0b response some place else..

slowsleeper

The cams that you are running are totally different from his so you can't even compare it. This is what HT has turned into, I'm running stage X cams with pretty much stock primaries and VTEC at 4800 so even if you are on Pro1s, etc, your VTEC HAS to be low as well!

The primaries/low cam on his graph hasn't even peaked yet, its still making power to 6700. Everyone knows what happens when VTEC is engaged too early right?

So based off of what you are saying, VTEC should be set at 5500ish on this graph huh? (Its only a 82x89 on pump gas btw)


OP, its about the combination of parts, think about what was posted and go from there.

DDTECH

Tou.. so lovely.

Runnerdown

This thread should be called. " I bought a bunch of parts that I thought were upgrades, then I learned I don't know how any of them work"

Changing a bunch of parts at one time without quite understanding how they come into play together and this is what tends to happen. Good luck optimizing your setup.

98vtec

just curious, but where are your cams set right now?

Local

+1in/ +2ex on the markings. They're the older sk2 ones, been told those are a little off.

cruizinmax

iTrader: (2)

If you look at just the torque curves you're making much less torque with the new setup from 2-8k rpm. It only makes more torque from 4-4500rpm from the CAI resonance. Changing your vtec crossover is not the answer.

My guess is the intake manifold is more restrictive than your performer x.

DazeMS

your not listening.. but hey, whatever. cause comparing apples to oranges is a great way to make a point. Further more, the cams are not that different and should have made more power regardless over my setup. 6700 is not effective when dealing with manifolds designed around certain criteria. There is inherently more to it then just vtec , but in HIS graphs, his vtec is not helping, especially with cams designed to work with more rpm when you dont have a manifold to match them. carry on..

DDTECH

Cam need to be oved, your torque curve on the new setup is flatter, and does carry a bit longer before dropping off. I would have kept the performerX manifold personally, thats just me. The second setup just needs to be dialed in more.. nothing else.. Moving vtec wont do **** right now..
Get more seperation and see what it does, +1/+2 is too close, these cams like seperation.

J.Berta

The OP should have had the cams degreed in before take the car to get tuned. The tuner isn't going to know any of the clearances or what the exact cam timing is unless they are the engine builder too.

gutted-dx

iTrader: (1)

What exactly is a straight pipe? Also I'd think changing the whole exhaust/intake setup would benefit from moving the gears around to optimize power, right?

B_Swapped93

I'll bet he means something like a BC:S2 loud AF and annoying

Local

A straight pipe is just that, a straight pipe. Goes on in place of the cat.

DDTECH

Advance the exhaust to +4 and it should make a world of difference.

SR20S13

No, I've got a similar setup to him (little more aggressive on mine) and vtec is at 5800rpms, and he could show us his fuel map and prove it to you if you really want.