Jump to content
SAU Community

Recommended Posts

Who idea was the reverse staggered cams

Cheers

Darren

What do you mean by reverse staggered?

Tomei (For want of a different option) offer the following:

Poncam A :260 inlet and 252 exhaust at 9.15mm lift.

Poncam B: 260 inlet and 260 exhaust at 9.15mm lift.

I have a 256 inlet and a 252 exhaust.

Upgrade option on the inlet side appear to be to go an extra 4 degrees and more lift picking one of 9.15, 10.25 and 10.80.

On the exhaust side the increments are in four degrees also although I didn’t look at the lift.

Inlet 256 degree 9.25mm lift. Opens TDC. Closes 41 degrees ABDC. For 221 degrees duration at 50 thou valve lift.

Inlet 260 degrees 9.15mm lift. Opens 1 degree ATDC. Closes 43 degrees ABDC. For 222 degrees duration at 50 thou valve lift.

Inlet 260 degrees 10.25 lift. Opens TDC. Closes 43 degrees ABDC for 223 degrees duration at 50 thou valve lift.

Inlet 260 degrees 10.80 lift. Opens 1 degree BTDC. Closes 41 degrees ABDC for 222 degrees duration at 50 thou valve lift.

Exhaust 252 degrees 9.15mm lift. Opens 42 degrees BBDC. Closes 8 degrees BTDC for 214 degrees duration at 50 thou valve lift.

Exhaust 256 degrees 9.25mm lift. Opens 46 degrees BBDC. Closes 7 degrees BTDC for 219 degrees duration at 50 thou valve lift.

Exhaust 260 degrees 9.15mm lift. Opens 47 degrees BBDC. Closes 3 degrees BTDC for 224 degrees duration at 50 thou valve lift.

Collapsed mufflers, cat....

This seems the obvious and first area to check. But there seems to have been a lot of effort concentrated on boost control and cam timing. This brought about bottom end improvements, pointing to decent outcomes. Then comments/suggestions drift quickly into using bigger cams which are effectively going to simply shift the curves to the right and sacrifice low/mid range.

The original point of the thread was a reasonably low peak power number for the general engine spec.

The torque curves shown in this thread show something that hits a peak and then just falls away.

Troy's suggestion is where the investigation and power hunt should have started, and does not appear to have been addressed. Disregard whether its a quiet or loud exhaust system. Eliminate the muffler/s and cat, do a trial run on the dyno and establish for certain just how much they are holding things back. Low cost, low effort test. And you can then make an informed decision on what to do.

Many instances where old/collapsing cat/mufflers are choking flow, and also where there are hidden neck-downs to quieten down flash name brand Jap exhaust systems.

  • Like 1

(New) result seems fine to me, he's not on e85 and it's a conservative boost level with cams geared at response over power.

My results are similar boost but on 260/260 + e85/hub dyno and your 70hp ahead at 4000rpm, but only 40hp behind at peak power.

Throw some more boost and some jungle juice if your chasing more outright power IMO

(New) result seems fine to me, he's not on e85 and it's a conservative boost level with cams geared at response over power.

My results are similar boost but on 260/260 + e85/hub dyno and your 70hp ahead at 4000rpm, but only 40hp behind at peak power.

Throw some more boost and some jungle juice if your chasing more outright power IMO

Cams are actually set to chase powahs.

Wish I could get a chart of yours on 98 but nevermind.

Not sure how much more boost there is the controller is at 82% or thereabouts something just over 20lb.

Our R32 GTR had lost power before we pulled it off the road for a new engine build.

The other night i was dropping the exhaust system to remove the rear heat shields so i could drill holes to bolt a battery box down in the boot area.

Center muffler was collapsed, it was a 3.5" system, clogged down to a 2" (or less) system.......never would have guessed it without looking.

I made the same as you did on 98 at 18psi with smaller turbos and standard cams.

Do you have a dyno sheet to share?

The one in your build shows less power @ more boost compared to djr81s 2nd dyno sheet.

6kw (10hp) difference is f**k all and between a -9 and a -5 setup there should be a lot more then that,

As for cams being "too small" if someone can use a 260° in a 3.2 and make 475kw (645hp) why do you need bigger in a 2.6 when you aren't even making 375kw (500hp) yet

As has been said by multiple people, give up on cams and look else where

I dunno maybe a 32 has a very slightly longer stroke than a 26 and therefore doesnt need a long duration cam.

What I am trying to reconcile is the following (In no particular order).

Why the thing appears to have so much torque in the midrange when the -5 turbos arent known for this.

If the exhaust is collapsed (And yes at some stage I will get it checked) how does this fit up with it holding the 20lb boost in the top end - would it not struggle there?

How to differentiate between the theoretical changes for each of the cams, so what would a larger inlet do in this circumstance in isolation. Same question for the exhaust cam.

Do you have a dyno sheet to share?

The one in your build shows less power @ more boost compared to djr81s 2nd dyno sheet.

Oops must have been e85 results. Haha

But here you go for direct comparo. He says around 20 pound and this was 20 pound 98 and 3 years ago.

Cam Gears in and dialled up

Blue line before, Green line after

20120806_152641-1.jpg

Hence why I say get it on a dyno. If he has -5's on a built motor then stop messing around.

  • Like 1

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • It's about the same time for me from Bunnings, or the Fasteners. My big push away from takeaway food, and gluten in general keeps me away from the Bunnings Snags too! Weather up here, I've been out for two walks today in the beautiful sunshine. Had a few little drizzles, and some wind, that honestly, a tin of beans and I could compete on how harsh she blows Thankfully, being this bit inland, we're not getting anything much really. Will probably pick up a bit more when/if Cyclone Alfie decides to come ashore. A few areas in the GC though, and south into NSW are really getting smashed though! Right now, I'm just annoyed Alfie hasn't hit, as I'm not allowed to crack into the BBQ foods like the bacon and eggs until the Cyclone hits "In case we lose power"...
    • I love fastener joints, the price difference between them and joints like Bunnings or Super Cheap is amazing, and they either have exactly what you want, or they can get it to quick They have even given me some for free when I only needed a couple of specific size In saying this, I have paid premium for fasteners from Bunnings if they have the sizes I need, but only for convenience really, as my local is only 10 minutes away, the Sushi joint near them is also a consideration  How's the weather Matt? Stay safe mate
    • Wideband is worth setting up if only for tuning purposes. I would not mess with the ignition system unless there's a misfire. HKS crank trigger is popular out here for the relatively easily sourced Denso crank sensor, not a bad idea to install as well regardless of power level on a standalone. Boost leak test is worth thinking about. Oil pressure sensor tied to a fuel cut isn't a bad idea either. Getting the tune figured out is a good idea. Without putting eyes on it and getting under it there's no way for us to tell you exactly what it needs but most likely you're down to the last 10% that will make a big, big difference in how happy you are with the car.
    • Doing a refresh of my 33 and can see a few websites stating they sell the entire main carpet for our cars, but they all have generic photos which is fine, i understand they are custom made to order.  Just seeing if anyone has got it done or had any experience with this, as i would only want to do it if the fit and finish was as good as oem https://carmatsdirect.com.au/products/moulded-carpet-or-vinyl-for-nissan-skyline-r33-1993-1998-coupe https://knoxautocarpets.com.au/moulded-carpets/nissan/skyline/skyline-r-33-1993-1998/
    • Any plans for E85? If so, add flex fuel sensor.   I'd probably add in the sensors I mentioned above if the Link will support using them for engine protection. With water pressure, you need to be able to effectively set it that "If temp > X, and pressure = atmospheric, shutdown" as at running temp, you should be able to read pressure in the cooling system. If pressure suddenly disappears, it means the water went some where, and this is a quicker reaction than waiting on water temp to go up (Which, can take a little longer than you'd like, considering it now has to wait for hot air to heat it up) Oil pressure, Oil temp, both would be on my list too if you're looking to add sensors. Wideband O2. And at least one EGT sensor. If you're feeling deluxe, put in individual runner EGTs. Single EGT sensor is more so forget about a specific number, get used to "What is normal EGTs", and then keep an eye on it, if it starts going away from "normal" it's a sign something is wrong (Also, things like the tune can still start going out of spec, but EGTs may not show it, for example one injector starts running leaning, so ECU richens everything up, now 5 out of 6 cylinders are rich, and running cool, with one cylinder lean and running hotter, so it's not perfect) Then there is your other things to look at non sensor related, but you may have already done, or have underway, and that would be things like building a sump for more oil, and better oil control under high G-Forces (Cornering, brakes, acceleration). Basically, the above is worth looking/thinking about, if the ECU can do protective stuff with it, and you continue to use it how you are (Drive it to the track, thrash it, drive home, repeat once every 3 to 4 months)
×
×
  • Create New...