Originally Posted by OCG35

Okay – so the new tricks have been installed…

Much thanks to Derek (dsskyline) for the great deal and accommodating payment for JWT S2 cams (thanks brother!) – and thanks to Howard (and Rich) at Technosquare for the install and coming in below estimate! Also, Ben at JWT for the multiple questions & answers and Jim Wolf himself for being so gracious with his time checking the cams and discussing project with me. And SPECIAL thanks to Shawn Church at CAT for his generosity with tuning this thing! A few more tweaks need to be made, but I know Shawn is dedicated to get it right – some of the best customer service ever! Thanks a bunch Shawn!!!

So – The car already had Stillen intake, with thermal coated Z-Tube, TBS, MDE ½” iso-thermal spacer, DEO blueprinted machined upper & lower collector, Crawford HFC, Stillen cat-back exhaust, tuned with Osiris running 3.7 FD – it was a blast to drive and did respectable at the track and on the dyno… here are pre-cams & headers dyno vids – vid was taken to record sound pre and post headers (dyno sheet at bottom has pre and post trq & hp):

more for pre & post header sound comparison:


Never satisfied, I’m always on a quest to squeeze more power – I call it my Japanese Muscle Car! All the low hanging fruit was done, not much more left… I contemplated a full build, but wasn’t certain the time, effort and money would be worth it unless I was building an FI beast (which I couldn’t do satisfactorily for les than 15K closer to 20K)… I’m fascinated by making NA power – so I picked the brain of a few people, studied a bunch of stuff and decided to see if cams and headers would be worthwhile (a few very notable industry ppl thought it would be advantageous).

I wanted mild cams – because even though I don’t drive the car much, I want it to be a streetcar that performs well on the track… and my main concern was not losing low-end torque – so I chose JWT S2 cams. To help offset the minor bottom end loss, I chose Crawford headers (searched a bunch over the years and these are the longest tubes while still keeping cats that I know of – and they have reported good trq for others). Since I have 3.7 FD (in an AT), its hard to make it through ¼ mile in 3rd gear, I run out of rmp – so I needed to be able to redline at 7500 (my theory was also to take advantage of the cams up top)… in order to do this I researched what parts where a must to keep it safe – and chose JWT valve springs, rev-up rod bolts (stronger than non-revup DE) and rev-up oil pump (again, stronger components) – the revup parts do nothing for power – they are designed for higher revving engine and seemed to be a cost effective choice for my project.

Here are some pics of the headers – I wasn’t at the shop when internals went in (wish I could have got pics)… not many of us see our car with the heart taken out:





All was re-tuned with Osiris – I was really hoping to see 30 hp, 20 trq (just my personal wish)… and while there were gains, I didn’t get close to my wish. Peak HP gains was about 18 and peak trq 8-10… however, the trq gain is across the entire rmp range with a relatively flat curve… and hp gain is maintained well beyond previous 6500 (its 10 hp higher all the way to 7500) – so overall this should help with my goal for the track.

For the Dynapack haters, remember this is for gains, its futile to compare these numbers to others (than my own). The pre cams & header is the bottom thick green line (one week before install), the post cams & headers is thin green line on 91 pump gas and yellow on MS101 race gas (no difference in this case, which is unusual because previously I when I tune with race gas more timing advance can be made and a bit more power… it didn’t make a difference this time (previous was 105 though)… anyway, FWIW a few years ago I dyno’d 270 on this machine and 250 on Stillen’s dyno jet and 245 at Dyno Shop's Dyno Jet in SD – so I figure I’d be 270-275 on those machines (but it’s always different – there really is no point in comparing those numbers, but I know it will be a topic).


There are a few things still to be worked out… off idle to about 2500 is a total slug (really bad) then trq kicks in HUGE). This is a big problem, because it’s actually hard to predict in certain situations. Shawn has agreed to spend some time with it and we have some ideas that will fix. Also, I have (what I consider) excessive valve tap, more prominent when engine is up to normal operating temps (I’m still working on this one)… and one of the O2 sensors is acting up (this should be an easy fix, fingers crossed).

Here is a clip of the post install dyno


Sound clip post headers


Here’s one from inside the car – this is in a small garage so the sound is magnified – the car is not as menacing as it sounds in this clip… the end of the clip is pointless for this thread (I was trying to capture the valve tap for another thread – I have better clips of that if anyone is interested I’ll post the link to that thread)


So overall, I’m not horribly disappointed, nor extremely satisfied… I will say its not worth the expense – this is the only mod I have done that I would not recommend to most people – everything prior to this I would (and have) recommended to anyone looking for more performance. This project has satisfied my addiction for a while though (well not really, there are other things I’m doing, but that will never end).

I know it’s a long post – but figured I’d say it all at once for anyone that is interested.

Originally Posted by Frostydc4

Did the cams lean out the AFR before you did the retune?

Originally Posted by OCG35

it was a bit lean

Originally Posted by Frostydc4

Just curious how lean? Was it between 1/4-1/2 point lean (say @ 13.25-13.50) or was it more (@ 13.75+)? Thanks!


The reason I'm asking is because I'm going with more agressive cams very soon and I want to get an idea of how they will affect the tune. Thanks.

Originally Posted by OCG35

Here's my little project - relatively complete... I know its not a "build" per se' but I like this area for NA stuff and I got a lot of good info here... so I thought I’d share FWIW.

Its copied from my post on Driver - thanks for the info out here guys... this side is way better than any other area on this site, driver or any other!

Originally Posted by Motormouth

The lack of tq that low and the big 'hit' can be an exhaust leak, no? Might want to get the header bolts checked out because they can come loose after the car heat cycles.

And get a better, lighter exhaust you are robbing yourself of power.

And the noise could be the clearance for the buckets on the cams couldn't it? I thought they could make a similar noise if they weren't shimmed tight enough. But I am not 100% on that.

Enjoy and don't regret. You got more power and I honestyly think you have more in it.

Originally Posted by __jb

I think that anytime you change rod bolts and cam shafts, it's classified as a build.

Gains are hard to come by on NA motors, but it looks like you're making some pretty good power... How is it to drive? Seems like it would be a lot more fun to drive now...

Nice post!

Originally Posted by Motormouth

I can almost guarantee the stillen is robbing power. alot of it. I think that has been shown to be true. especially if you are revving higher. and it's heavier than stock iIRc.. get rid of it ASAP. before you bother to retune. and a leak at the headers doesn't sound the same, the header bolts are known to loosen themselves after heat cycling... it takes ten seconds for a mechanic to check them.... worth the time IMO.

if you are serious about the engine, why skimp on the exhaust or prevent it from working better?

Originally Posted by Motormouth

I mean by running an exhaust that will get you more gains. maybe it's different for the sedan, but on the Z it's weak.

I thought you had a G35auto coupe. things may indeed be different for the sedan.

Originally Posted by OCG35

So as planned, Osiris tweaking next week to get it dialed in – I’m hoping the Titan-esque ETC update is the fix.

Originally Posted by __jb

Can you post a link that talks about this ETC Update? You are talking about Electronic Throttle Control, right?

I have all the current betas, but haven't loaded the latest beta yet, nor have I read about a new ETC breakthrough for G's with cams... But!!! Since I have a G with cams that is currently on the dyno, I am very interested to read more about this.

I did notice a pair of buttons that mentioned OEM and something else relating to the ETC control. I thought it was just a way to reset the ETC to the OEM system. I talked to Jared last week... I'm surprised he didn't mention it. The computer I have Osiris on is currently in Orlando or else I would just look at it.

Thanks...