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Thread: Cam tuning info and guide

  1. #31
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    Default Re: Cam tuning info and guide

    I'd have to know your runner length, average cross sectional area, and the distance to the back face of the plenum to even come close to guessing! I know those cams should have a sweet spot in the 5500-7500 range, but it all depends on the flow capabilities of your header, the hot side of your turbo, downpipe choice, etc... on top of the intake side of things.
    -Jake
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  2. #32
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    Default Re: Cam tuning info and guide

    Jake, it's just mathematical manipulation. 6.0L of air @ 14.7 absolute psi = 3.0L of air @ 29.4 absolute psi. Gas laws in action, baby!

    I do see where you'd correct me though - it's my own fault, really. I really hate trying to dumb things down, and generally I do it without explaining the calculations - good job on straightening that out, though The fact that a 3.0L motor physically WILL NOT ingest more than 3.0L of air in a complete cycle, is exactly why you do not exceed 100% efficiency without proper intake harmonics.

    The problem stems from (as I mentioned a moment ago) you can look at any particular mass of air as 2x the volume @ 1/2 the pressure (letting you think that you have more volume of air coming in, ala D-Dayve's post) The gas mass will remain the same.

    Is it mathematically valid? Sure. If is correct, according to physics? You bet. Is it what is actually happening - NO. It's a mathematical manipulation of the actual events at hand.

    The reason I have such a problem of this manipulation, is that you completely ignore the fact that the density of the incoming air/fuel charge is increased, and so the speed of the flame front is changed. This GREATLY effects MTBT, and is the #1 reason I dislike 95% of piggyback systems used on the 7M!

    Jake, would you like to add anything else? I always love a good discussion!

  3. #33
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    Default Re: Cam tuning info and guide

    Good point!
    But I do think that the density is taken into account on the basis that the mass incoming per cycle is always squeezed into .5 L for each cylinder. Thus if the mass flow rate increases (read freq for a karman sensor), the TCCS is going to know that the density has changed.

    This works as long as everything is stock, which is why when you *trick* the TCCS to avoid fuel cut, you increase the timing and run the very real risk of detonating. I'm not sure if MAFT- pro addresses this for the supra yet, but I know for GN and DSM applications, you can not only monitor, but adjust timing advance to correct for airflow corrections. Messy, but effective if you know what you're doing.

    I get what you're saying about mathematical manipulations and such, but to say that the turbo is pushing 6 liters of air into a 7m is a tad bit on the uhm... not right side of things for my liking. A roots SC, sure, it doesn't make pressure, it moves air. In fact it could be adjusted to move exactly 6 liters of air into a 7m every cycle. And as you said, the result is 3 liters of air at 2 atm. But you and I know that turbos are much cooler and sexier and don't work like that.

    Is there a better place to continue this discussion? I'm trying to keep it on cam timing, but there is just so much more meat to chew on the topic of extracting power while not extracting connecting rods from the side of your block...
    "I've got a machined head, It's better than the rest!", Read this

  4. #34
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    Default Re: Cam tuning info and guide

    Start another thread man!! Matter of fact, doing that right now (and you gave me the perfect thread title )

  5. #35
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    Default Re: Cam tuning info and guide

    A cams question - thanks in advance for your reply in layman's english.

    I had the stock cams replaced with TODA 256's. Since they came used from Gord Duax they didn't come with a degree card. I found someone that knows about this kind of stuff and he worked on my car and dynoed a couple nights ago at DC Racing on a rear wheel roller dyno. 408.6 HP / 390.9 Torq. We were hoping for over 500. I have a stock bottom end and alot of mods that people in the know have told me should get me 450 hp +.

    I dynoed in MI with Emanage blue and E01 with a Greddy TD-6 20g and put down 332.4 hp / 344.1 Torq on a wheels off dynapack in Royal Oak Oct. 24/06.

    Two years later with Eman & E01 out for a Maft Pro and it did 363.5/353.9 on a rear wheel roller dyno at Victory Racing Oct.27/08 with a boost leak in the IC and a crack in the TD06 on the hot side so we replaced it with a GT4088 and patched the hole and street tuned it at EZ Autobody in Ruthven and the car pulled like a bat outta hell. It felt like a 450 hp + beast. But it was November and fairly cool out.

    Since then due to a lil low end lag we put in a new GT35R and the TODA cams and ran 408.6/390.9. I was under the impression that the cams should add HP since Javi in Puerto Rico who put TODA 264's in his MK3 turbo added 57 hp and Zazzn with his 272 BC cams added over 80. The 40 increase in my case could be solely attributed to the boost leak being plugged since the hole was the size of a quarter.

    Mind you the TODA cams are not yet degreed and are just TDC. I did notice the they moved the power band up 400 rpm from 5400 to 5800 for HP. A couple guys commented that with a stock bottom end and a bunch of bolt ons I should be happy with 408 hp. Well when some guys have put down over 600 and 700 with stock bottom ends why should I be happy with 400.

    Would replacing the Maft Pro with an AEM EMS help?
    What about a FFIM and FMIC?
    Or would 720 injectors be the way to go?
    Or should I build the bottom end?
    I can't see degreeing the cams 4 degrees advanced on exhaust and 2 degrees retarded on intake as Javi did adding that much. Gord said to degree them to 114-115... which is Greek to me.

    Well what do you think?
    Mods: 2JZ-GTE; Haltech PS2K ecu, IQ3 display, 3 Bar Map sensor; HKS SSQ Bov; K&N air,oil, cone filters; RP 10w30; AEM Uego A/F display gauge, wideband, BC; Borg Warner S366 ETT Turbo; PTP blue turbo blanket; custom intake piping; Mallory 4309 FPR; Walbro 416lph; Aeromotive 12304 fuel filter; E85 flex fuel sensor; Lucas 1200cc's with EV1 clips; built TH400 with Gearvendors and B&M QuickSilver shifter; 2JZ-GE bellhousing; Shaftmaster aluminum 1 pc. driveshaft with safety loop; SP torque converter & flex plate; Prosport trans temp gauge; RP Max ATF; Earl's cooler; Revshift poly motor mounts; Snow Performance Stage 2 MAF/MAP Boost Cooler Kit; PWR rad with GReddy hi-pressure cap; dual electric fans; CXRacing FMIC kit; CfFX IC block off plate; Tanabe Medalion Touring; Cusco rear strut bar; Suspension Technique sway bars; Xenon HID 6K head lights & fogs; clear front signals and side markers; EDM folding mirrors; JDM Turbo A duct; SAP lip spoiler, Bomex sides, Bomex rear unders; GT Factory Diablo Door kit; Denso Iridium Power IK24's; Stern Face III Beast hyperblacks 18x8.5 & 18x9.5; Vredestein Ultrac Sessanta 245/40/18 fronts & 275/35/18 rears; Wilwood - SS brakelines, heavy duty powder coated adapters, BP10 Smart pads, forged Superlite 4 piston fixed calipers, 570' fluid; Centric 13" cross drilled rotors; Tokico struts; CustomFit Toy02 plush mats; Pioneer 450 MP3; Garmin Nuvi 7600; Clifford 590.2X. BrandonB custom fab/mod/wiring/body/dyno/tune. Pics in album.

  6. #36
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    Default Re: Cam tuning info and guide

    I have an pre 88.8 7mgte. Fully ported/polished, 5 angle valve grind, new o/s 1mm precision valves, BC Stage 2 cams, springs, and retainers; professionally installed and shimmed; drift motion 60-1 turbo with .70 ar, tubular ex. mani, 50mm wastegate, hks ssqv, full intercooler kit, aeromotive afpr kit, walbro 255, aem wideband, etc etc etc.... my issue is the cam timing. just got fidanza adj cam gears. dont have a cam degree wheel, wuz just going to leave them in stock position at TDC of #1 for reference once valve covers were back on. Which direction do i rotate the cam wheel to advance (clockwise or ccw?) ive read various things and everybodies runs different with sacrifice of power at some point in the rpm band. even just a baseline adv/ret to get the damn thing to idle semi good, not cook thru fuel like a helicopter, and have overall decent power band is all im looking for. not gonna take this to the track, just a weekend driver sorta play toy is it. anything helps. thanks.

  7. #37
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    Default Re: Cam tuning info and guide

    I have the BC stage 1 cams, same adjustable gears & found installing the cams at +3 exhaust & leaving the intake at 0 to be a good setting, but every engine is slightly different.
    To advance the cams you rotate them in a clockwise direction.
    Dont forget to reset your ignition timing if you alter the exhaust cam setting.
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    Last edited by BLACKCAT; June 10th, 2010 at 01:49 AM.

  8. #38
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    Default Re: Cam tuning info and guide

    Very helpful!!

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