Jump to content
SAU Community

Recommended Posts

  • Replies 45
  • Created
  • Last Reply

Top Posters In This Topic

So in your opinion cams are a must for maximum efficientcy. Thats a fantastic difference from 260 to 300. I think with the housing that Robo has and most certainly my .82 there could be big gains in cams of say, 256inlet/260 exhaust due to the freeing up of the exhaust and because the turbo is is now very efficient but the motor less so.

When the cams went in the first thing we noticed was power was up slightly but it allowed more ignition to be pushed in which is where the power picked up noticeably.

I was always taught that anything you can do to reduce the restrictions on the hot side pays off by reducing exhaust gas reversion , better cam profiles help achieve this by opening the exhaust valves further and for a bit longer .

The trick seems to be matching the valve timing with the static compression ratio once the exhaust restrictions ie exhaust system / turbos hot side have been reduced . It falls in step with the greater gas throughput (air and exhaust) for less than or equal resistance to flow - pressure rise .

A .

Edited by discopotato03
Robo, The Z32 AFM what peak voltage are you seeing?

I run GTR 444 injectors. They flowed 440cc at 36psi and 480cc at 40psi.

At base pressure they were maxed as 260rwkw approached (Z32 saw 4.78volts) to hold a 11.8:1 afr.

A 1afr point drop at idle (adj fpr) and fitting cams has seen them go to 302rwkw at 90% duty and a flat 12:1 afr. 302rwkw I'm now seeing a flat 5volts on the Z32.

I'd really like a 3.5" exhaust with 2 large body mufflers in an attempt to keep the noise down.

Not sure, i will look at the volts next time.

robos i had the same turbo set up on my rb25det a few years ago. with the same problem. too much back pressure with a/r.63 exhaust housing so runs out of flow at 22psi rougthly 6000rpm. you can fix this with a/r .82 internal wastegate exhaust housing im quite sure that gcg in sydney can source one. i changed my mind last minute and upgraded to gt3040 600hp turbo with a/r .82 exhaust housing instead. as for the boost falling away from 22psi to 19psi. this is something that you will really struggle to fix running an internal wastegate. are you running a 1 bar actuater? you can buy these from gcg in sydney as well or hks one from nengun.com. the only other alternative to hold more boost is to run 24psi which will hold over 20psi at 6000rpm but obviously no good with stock internals.

and for safety sake go and get your injectors hi flowed at avo in melbourne , cheap insurance. dont listen to anybody that says hi flowing standard injectors effects idle e.t.c. i had absolutely no problems with mine.hopes this helps cheers carl. p.s. i never got anywhere near an 11second pass with this set up. too much wheelspin down low and not enough flow up high in the rev range but very nice mid range for the street! but having said this looking at what you got with the hks 2535 you and your car are both freak performers. i should have got you to punt my car down the quarter mile probably would have pulled an eleven!

post-6176-1224990166_thumb.jpg

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

    • Great work! Give it a clean up with some Emery paper, and I'd run a thread die over the threads too to clean them up. It will make reinstall much easier, and also life easier for the next time it needs to come out.
    • I'm not a fan of high humidity, it's one reason I don't mind being further inland out Ipswich, except the last 3 odd years, the drought broke, and it won't stop raining, which is making the humidity nearly unbearable when the rains are in during summer! For me, my body hates the cold, once the cold sets into my body, I'm totally screwed. I end up with severe muscle spasm in my back/shoulder muscles, and it feels like someone is trying to tear the muscles out. I have no issues with it getting stupid hot, so long as the humidity goes away. So the last 3 years as above, have been woeful! Ha ha. However, June 1st, and I'm only just converting from shorts and a tee, to long pants and a t shirt. And that's mainly as it's a bit wet and miserable and I wanted to work on a car.
    • I much prefer colder weather to hot weather, and especially prefer cold to hot and humid, Goulburn does gets pretty warm in the hotter months, but, I've found the humidity there is not as painful as even Sydney, the humidity up north is to oppressing for this old rooster  In saying this, it does get rather "nippy" in Goulburn for early morning, late in the evening walks, but nothing that a layer or two, some thermal gloves, and a beanie doesn't fix to make it an enjoyable experience, which is much more bearable to me than the oppression of heat and humidity,  especially at night when your trying to sleep If I recall correctly, a "wise man" once said that the "Southern Tablelands" was gods country, and I will not argue that point with him for the fear of a "permaban" LOL In car part related news: My intake is currently in Botany getting processed for the last leg of its shipping journey to my door   
    • Had a go at the stuck crush tube this afternoon. Tried things like grips and a chain wrench first but wouldn't just twist straight off. So got to work with a drill. Started small and kept a depth stop on to make sure I didn't drill into the bolt. Made a line of drill holes all the way up and enlarged them. Then a combination of chisel and Dremel to split it all the way up. Levered the split to get oil in there and eventually it gave a bit while levering. Worked it back and forth with loads more oil till it was spinning freely, then with grips I could work it downwards and off. And no significant damage to the bolt (not by me anyway - just the 27 years of rust)
    • Well, I'm tired. I'm tired because about 4PM yesterday, before today's appointment someone immediately bought my bumper. They couldn't get it any other day as they're on the way back to NSW. So I had to do that big GTR conversion I had been planning. Unfortunately, the information on SAU about what you need and how this is done is incomplete. So what should be a simple bolt on affair, yeah, it's not. Did you know if you use all GTR items the bonnet won't close? This little manuever sent me into about 1am the night before trying to dodge a way to get it closed. I will have to revisit this in the next few days  - or maybe not, I may let a body shop figure it out. It all needs to come up and my motivation to pull the bumper off is low. It also seems to hit things in the bay where the GTT bonnet didn't. Yes I used 100% new OEM GTR items. Today, I had the joy of driving to the dyno looking like this: Given I had roughed in the fuel and given sensible but pretty conservative timing, I didn't really bet on having the car drive out any real difference than when it drove in. Sadly due to a miscommunication and laptop fun and games (and almost bricking the dongle, prayers and firmware updates indeed), I ended up using HP Tuner credits to licence the car that was already licenced. So in the end my laptop was used. It turns out my butt dyno is still well calibrated after all this time. The 325kw was on 74% Ethanol, the 313kw line was on 98. The other line is the 'before' line which was 281kw. While the numbers are pretty low, they're pretty in line with what you'd expect. Even if US dynos bump the whole result up about 50KW, gaining 10-15% is similar gains.  The curve of the cam is pretty much spot on with what was discussed as well. All this said, it still feels bad to not see the number you secretly want to see. Even if the car drove great beforehand, and I knew pretty confidently the car would drive out much the same way it drove in due to the nature of a wellish dialled in LS1 not gaining much if anything at all from being tuned from where it was. As expected, the car isn't particularly sensitive to running it at anywhere between 12.0 and 13.0 - And the initial timing at 20deg and 12.0 made 308KW. So 3 degrees of timing, and leaning it out to 12.7 for 5kw, anything above stopped giving any benefit until E85 (which has an additional 2 deg as before). Car itself behaved entirely fine. I found out that 100C = 1.15V! IAT at about 7pm was 19C. I might mess with the bonnet mounting.. but given the REO NEEDS TO BE CHOPPED TO FIT A GTR BAR this is possibly something I may leave gathering (more) dust until it returns to paint jail.
×
×
  • Create New...