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Location:
Canberra
Registered:
May 2002
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what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 08:59
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Since there are a few camshaft profiles available from the factory for the 4AGE/GZE, what should be the best to aim for with a turbocharged 4AGZE? the bigport (long duration, big lift) small port (less duration & lift) or GZE supercharged cams?
I'm not sure if it is cams contributing to my problems, but my 4AGTE is lacking power from 6000rpm onwards. the power climbs hard as it hits boost, then flattens out from 6 grand. This is with 15 psi boost, and bigport 4AGE cams.
any advice appreciated.
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Toymods Board Member
I supported Toymods
Location:
Turramurra, Sydney.
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 11:12
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That's interesting. I'm planning on going for the bigport cams too, they are a fair whack bigger than the smallports.
Surely the lumpier bigports would produce less bottom end & a screaming top end (as we know & love) whereas the smallports would be more inclined to low end power?
Maybe some adjustable cam gears would help.....
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Location:
Newcastle
Registered:
September 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 11:27
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What size exahust do you have? and turbo? as it sounds like it is hitting somesort of restriction
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Location:
Canberra
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 11:37
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From the way the dyno graph looks, you would think it was hitting a restriction, but as for what, i dont know.... 
Exhaust is 3" with two straight through mufflers, no cat
Turbo is 3SGTE CT26 with TO4B 'V' trim compressor wheel
Intercooler plumbing is 2 1/2" to intercooler, I/C core 600x350x60, then 3" plumbing to throttle body (RWD 4AGE manifold)
Computer is a haltech E6K
cams are set as per factory timing.
HELP! I need that last 20kw in the top end!
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Location:
Newcastle
Registered:
September 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 11:42
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What power is it makeing? if the turbo has a large wheel in a housing ment for a smaller wheel then that can create a restriction.
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Toymods Board Member
I supported Toymods
Location:
Turramurra, Sydney.
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 11:42
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You pulled the T-VIS out, right?
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Location:
Canberra
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 11:56
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Yes, TVIS is long gone 
The CT26 compressor housing is by no means small, I dont think its the restriction. this turbo had no problems making more power all the way to redline on my previous 3TGTE.
Its making 150kw at the wheels before flattening off at 6000rpm
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Toymods Board Member
I supported Toymods
Location:
Turramurra, Sydney.
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 12:02
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Do you still have the dizzy or are you running twin coils? If dizzy, maybe the spark's not coping?
It's a tough one, I wish I could be more help.
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Location:
Perth
Registered:
September 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 12:09
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Hey
This isnt going to help you but i think im having the same problem with my 4agte too.. You seem to have no restrictions at all + a damn big turbo so im not sure why this is happening.. Is the haltech tuned 100% perfectly??
Im using a rather small r31 rb20det t3 turbo and stock gze ecu though so i think thats my problem.. I ran a 14.0 @ 98mph and the top end was definatley not there. Didnt feel like pulling after 6000rpm..
Rb25 T3 soon to replace this turbo and we'll see what happens then..
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Location:
Canberra
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 12:18
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Bigworm: I'm running the GZE cam angle sensor, M&W ignition module, & twin 2 post coils for waste spark. no drawbacks there either! I've tried different heat range spark plugs, both steel & platinum, even tried closing down the gaps....
Sprinta: The RB20 T3's aren't a bad size at all. when do you get full boost? are you running 14psi or so? It should scream with the RB25 turbo, they are considerably larger, shame they are hard to come by & fairly expensive compared to the RB20.
thanks all for your suggestions! keep firing away, i've gotta get to the bottom of this.
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Location:
Newcastle
Registered:
September 2002
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 Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 12:23
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Maybe 6000rpm is the peak output of the std cams so it looks like maybe you will have to get some cams with eveny more duration and lift!  Just a thought!
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Location:
Canberra
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 12:27
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I hope not! I wonder what cams the 'bigger' 4AGTE's are running. Yogi's celica for example?
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Location:
Perth
Registered:
September 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 12:27
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Yeh the Rb20 isnt small at all.. Im not sure when i get FULL boost to be honest.. maybe 3000/4000 for full boost (15psi).. but it drops off to about 11psi as revs rise.. not cool
The rb25's are rare yeah but ive found one.. If it falls through and i cant find anymore maybe a vg30det ball bearing will have to do.. Might be a bit too big?
Im sure someone has an explanation for this
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Location:
Canberra
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 12:32
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whatever you do, DONT get a non ball bearing VG30 turbo! they have different spec wheels and are a lot more laggy than the BB.
If only the nissan turbos werent ceramic! i'd have one in an instant, but i need more boost 
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Location:
Montrose, VIC
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 12:33
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A long time ago mine made 141kw at the wheels on 14psi, with R32 RB20 turbo, JZA71 cooler, Haltech IG5 + Gasresearch LPG on a completely stock ae101 GZE (small port + cams), if thats any kind of reference.
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Location:
Canberra
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 12:36
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so the bigport cams in mine shouldnt really be holding it back....
mrshin: what has yours been making lately since you've upped the boost & a few other mods?
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Location:
Montrose, VIC
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 12:42
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Last time it was tuned was on a really old school dyno that wouldn't actually read power directly... aargh, my best guess at present is somewhere around 170. I'll have a number and graph for you in the next week or two, I'm gonna check it before/after I do some more playing with. Aim for after is 220. (New intake/turbo/fuel system)
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Location:
Perth
Registered:
September 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 12:48
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Theres alot of non bb vg30's going around which people have offered me but ive said no many many times hehe
Its a shame the nissan turbos are ceramic yeh  but its supposed to make it spool quicker so it better make up for it
Seems to be a few 4agtes floating around here.. well done
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Location:
Montrose, VIC
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 13:08
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Yeah, I shattered my RB20 one a long time ago, just detached itself from the shaft as they love to do. (was a cold night, the car seemed to be going harder than usual when it did it too, was taking a mates mate for a fright ride )
Also, aren't all the VG30 turbos plain bearing, as when the BB ones came out it was Z32 twin turbo VG30 time anyway? Not quite sure!
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Location:
Perth
Registered:
September 2002
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Location:
Montrose, VIC
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Mon, 24 February 2003 13:29
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I think it's Laurel. You could be right there actually - although didn't the laurel + cedric use the plain bearing black top RB20 and only the R32 get the BB RB20? I don't begin to guess the combinations of jap engines/cars. Seems to be if the manufacturer makes the car and the engine, then they make the car WITH the engine. Aargh.
Boost? I suspect it may have actually moved up over time (crappy turbosmart boost bleeder), also was a cold night. Plus I drive the thing like I believe it should be driven, regularly the exhaust down to the dump pipe join is glowing bright red (all ceramic coated too), so I guess I can't really blame the little bugger for letting go!
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Location:
Adelaide
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Tue, 25 February 2003 02:46
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Could it be possible that the 1600 is not producing enough exhaust flow to spin the turbos at hight rpm such that they are able to create sufficent boots airflow to continue making power? (in both cases your turbos are designed for larger engines).
Just a thought...
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: what cams for 4AGTE?? big or small duration?
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Tue, 25 February 2003 03:15
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speaking from no turbo experience here, but...
if spark is no problem, and you still have boost, then unless you have really bad ports, the duration will not be that much of a problem. the turno should go to higher rpm than a stock engine with same cams as you are forcign the air in....
my long shot would be that the valves are not sealing as well with the high rpm and boost. as i undwerstand it the twin cams have relatively weak springs, for the low valve inertia, and so may not be sealing as well when forced to work harder than in a normal NA motor...
what happens above 6000rpm with medium throttle?
could they be bouncing??
could there be any whacky ignition timing things happen at high RPM?? noise in the trigger signal perhaps?? a timing light on a dyno would see it...
just a few thoughts
Cya, Stewart
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Location:
Canberra
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Tue, 25 February 2003 08:37
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MrShin & Sprinta: It is my understanding that the BB VG30DET's came in the nissan leopard. I bought a complete motor a couple of years ago just to get the ball bearing turbo off it (only cost me $495 for the lot )
RobertoX: boost is holding constant to redline according to the boost guage
oldcorollas: i've never had it at part throttle from 6k, just flat out! why? what might change?
The valves couldnt be bouncing, as they are a non interference head. According to the data log, everything with ignition seems ok. anything interfering with the signal would surely cause a noticeable miss from the drivers seat??
I'd post up the dyno graph, but you cant upload to the forums anymore as far as i can tell
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Toymods Board Member
I supported Toymods
Location:
Turramurra, Sydney.
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Tue, 25 February 2003 09:09
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He means the valves might be bouncing on the valve seats. That way they're not sealing properly all the time.
I dunno, that's the first I've heard of something like that with the 4A...
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Location:
Bundaberg, Qld.
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Tue, 25 February 2003 09:57
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 interesting reading guy's....
i cant give any insight as to what the problem can be here at all.
apart from it sux.... we all want max power achievable with-out bloody problems....
just wanted to mention (even though i never been on a dyno, just going by the feel of driving it) my little t-25 at 12psi, aw11 bigport ze, factory cams.
well it will push all the way from 3000rpm (spool-up) to redline, i do not feel any power lose through the rev range at all.
i only have a 2 1/2" dump pipe and 2 1/2" free flow exhaust, 2" pipe from the turbo to intercooler, and 2 1/4" to 2 1/2" pipe from intercooler to t/b.
correct me if i'm wrong, but i dont see anyone mention fuel.?
how is your fuel, not leaning out or getting to rich?
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Location:
Canberra
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Tue, 25 February 2003 10:38
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oh, that kind of valve bounce  is there a difference between the bluetop GE and the GZE valve springs? should I fit the springs from the spare GZE head to my GE on the car??
feral MR2: fuel is steady on boost at 11.7:1
ignition timing is 23 degrees at 15psi
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Toymods Board Member
I supported Toymods
Location:
Turramurra, Sydney.
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Tue, 25 February 2003 11:30
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If you have a GZE head & valvesprings lying around, it wouldn't be too hard to measure the spring rate of them. This is something I thought about a while back, but actually, now that I think about it, the GZE runs much smaller cams. So chances are, the springs won't be much different at all, I reckon.
I wonder if anyone knows for sure.....
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Location:
Canberra
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Tue, 25 February 2003 12:34
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I wonder if I should change them over to the GZE ones anyway. I have to take it all apart to change valve stem seals, & I figure springs from a 1990 GZE must have done less work than the ones I'm currently using from a 1987 bluetop GE.
I came across some info that stated that the 100kw smallport GE & supercharged GZE have the same camshafts. Is this for sure? anyone else found this?
FERALMR2: How hard do you rev your 4AGTE?
cheers
Phil
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Location:
Bundaberg, Qld.
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Tue, 25 February 2003 12:42
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well...... the tacho needle often see's the red on my guage.
but i normally shift about 7000rpm. but when i am cruiseing through town i drive like miss daisy, so i dont attract unwanted attension..  so i shift low, and most times dont even get it to spool. (much)
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Location:
Perth
Registered:
September 2002
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Location:
Perth
Registered:
September 2002
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Re: what cams for 4AGTE?? big or small duration?
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Tue, 25 February 2003 13:47
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TE72_Turbo: So have you had the vg30bb turbo on your 4agte?
Im finding it hard to get a 25det turbo so vg30bb may be the way to go.. Is it going to be too laggy/crap response in your opinion or should i keep looking for 25det ?
thanx
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Location:
Canberra
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Tue, 25 February 2003 21:15
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No, I dont have the VG30 on my 4AGTE, i originally bought it for my 3TGTE, but changed my mind in preference of the CT26 for its highflowing capabilities.
I havn't seen a VG30 turbo on a motor as small as a 4AG, but a mate of mine is currently fitting one to a 1.5L ET Pulsar, i'm interested to see how it goes. I fitted a VG30 turbo to an RB20 a couple of years ago, It made full boost shortly after 3000rpm, and had plenty of top end. Whilst they do seem a tad overkill coming from a 3 litre motor, remember that the 3 litre was designed to have full boost pretty much by 2000rpm. They are in fact on the small side for the 3 litre, as they were built to pull around a heavy luxury car, without upsetting the upper class customer who didnt want "laggy" performance. Manufacturers dont see our way of thinking, they want a turbo car that behaves like a naturally aspirated one!
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Location:
Perth
Registered:
September 2002
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Re: what cams for 4AGTE?? big or small duration?
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Wed, 26 February 2003 14:28
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ahh ok
thanx for the info man..
Im getting some sort of t3 sent to me atm.. Its definatly a ball bearing so im hoping its a rb25 but probably is a vg
Hope it isnt toooo laggy..
Thanx
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Registered:
June 2002
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Re: what cams for 4AGTE?? big or small duration?
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Thu, 27 February 2003 03:44
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Not to sure about this and not to familar with the cam profiles of the big port head or any 4ag for that matter but. NA cams typically have some over lap as opposed to forced induction cams having none if possible. At 6000rpm you may be hitting a point where the compressed air is simply getting forced down the exhaust. But I could be just talking SH#%.
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Toymods Board Member
I supported Toymods
Location:
Turramurra, Sydney.
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Thu, 27 February 2003 05:36
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| roger wrote on Thu, 27 February 2003 14:44 |
Not to sure about this and not to familar with the cam profiles of the big port head or any 4ag for that matter but. NA cams typically have some over lap as opposed to forced induction cams having none if possible. At 6000rpm you may be hitting a point where the compressed air is simply getting forced down the exhaust. But I could be just talking SH#%.
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This is where adjustable cam gears would come in handy.
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Club President
I supported Toymods
Location:
Sydney
Registered:
May 2002
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 Re: what cams for 4AGTE?? big or small duration?
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Thu, 27 February 2003 23:20
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mmm The Mythical world of Turbo Cam Profiles.
There are two schools of though that I am familiar with in relation to Turbo Cams. First of all tho a Cam is a cam be it Turbo or N/A so there are always trade offs. There is no such thing as a Cam that will Yield a Great bottom end and Top end power.
Ray Hall uses the theory that the Best Turbo Cam is a Mild Rally N/A Cam and claims that in his experience you just add 1000rpm to the advertised power band and that is what you will generally get.
The reason for the Rally cam preferance has been mentioned before.... Overlap ! you really don't want Valve overlap in a Turbo application, BUT overlap is a Killer at LOW RPM more than High RPM so I don't think thats your Problem. In Short LIFT Good, Overlap BAD 
I also Can't see your Valves "Bouncing" or sealing Badly with all that pressure (Boost) trying to force them closed ! BUT 4AGE Cams do have a reputaion as being kinda shithouse at any sort of regular High RPM or increased lift. But Hey your Using Stock Cams anyway !
If it were me I would suspect you are suffering from wastegate Creep. Are you sure your wastegate isn't being forced open slightly but the higher Boost pressures ? This is a Fairly Common Problem when Turning up the Boost and Not upgrading the spring tension on the actuator. Hell most actuators are designed to hold around 5-7 PSI, NOT 14 PSI. I'd start there
OH and the 4AGE may only be a 1.6 but the air Velocity due to it Being a 16V engine is more than enought to manage a CT26 IMHO.
And Last Thing I Have a Ballbearing Turbo of a Nissan R32 Skyline for sale. It is the Series 2 GTR32 Turbo so will Hold 14 PSI not 12 PSI has a Different Angle Cut on the compressor wheel and has the Rarest AR combination ! Cost me $650 will sell for $600 or Near offer. And yes it is a Ceramic Wheel !
For details see the other Thread so not as to Hijack this one !
http://www.toymods.org.au/msgboard/index.php?t=msg &th=10451
Hope that helps
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Location:
Canberra
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Fri, 28 February 2003 11:30
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Rod, you sure you dont mean GTS32 not GTR?
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Location:
Montrose, VIC
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Sat, 01 March 2003 11:57
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Could it be that your 'high flow' CT26 is just plain waaay out for the engine? It's got a bigger compressor but not turbine? My guess is that is actually just choking the bugger to death, maybe!
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Location:
Canberra
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Sat, 01 March 2003 12:32
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I'd be surprised, the CT26 has a bloody large turbine compared to any of the nissan/garrett combos, but perhaps the blade design is still restrictive.... damn it! there's just too many variables! maybe i'll put a Volvo engine in it
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Location:
Montrose, VIC
Registered:
May 2002
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Re: what cams for 4AGTE?? big or small duration?
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Sat, 01 March 2003 12:43
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Yah... There's nozzle size, wastegate size, turbine size, turbine blade trim, and no doubt plenty more. The nissan ones surprise me as, yes, they are tiny in every regard - but then I will never be able to look past 1JZ turbos - I cannot for the life of me work out how some have seen 220kw at the wheels from the manifolds, turbos, etc. on those bloody things!
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