Ipd Posted April 3, 2011 Report Share Posted April 3, 2011 Cam timing from turbo to N/A seems to a source of confusion and I haven't seen any published data on the comparison outside of duration and lift differences. This info alone does nothing to tell us if the lift on the lobe from N/A to turbo occurs earlier, later, or same. Since I had a local members car in my garage for an N/A intake cam swap figured what better time than now! *Take note, all measurements in degrees are compared camshaft to camshaft, they are not measured in crankshaft rotation. The Ipd cam timing tool measure and adjusts for camshaft degrees not crankshaft degrees. Car in question (1998 v70R) The engine bay Coming apart Turbo cams exposed Here's the setup. Degree wheel on the cam, reference marker fixed to the head, dial indicator on the lobe. I started my measurements at the standard 0.050 inch opening point. So duration starts and ends at 0.050 inch for both N/A and turbo cams Be advised the lift measured is total gross lift not started at 0.050 inch. Here's my findings as it relates to timing cams when converting from turbo to N/A: Intake: The N/A intake cam starts its opening 4 degrees sooner than the turbo intake cam. Given that, if you want to maintain the same overlap that a turbo cam set has you would retard the N/A intake cam by 4 degrees. Exhaust: The N/A exhaust cam starts its opening 2 degrees later than the turbo cam, AND the N/A exhaust cam has a total duration that is an additional 4.5 degrees longer than the turbo exhaust cam (as measured at the cam). So since the lobe lift starts 2 degrees later and continues 4.5 degrees longer you would want to advance this cam by 6.5 degrees to maintain the same overlap as a turbo cam set. Here's the cam timing tool setting the intake cam at 4 degrees retarded In this install we did just the intake cam only and since this car has a modified 16T (super60) the stock turbo exhaust cam will get put in straight up. Now the info above is just to maintain the same amount of overlap that a turbo cam set has in stock form. The conversation around exhaust backpressure (EBR) and how much overlap is acceptable is a conversation in itself. I'll be installed a set of pre-post turbo gauges permanently in my car so I can explain how to calculate EBR in the near future. Cam specs for 850 models (remember duration degrees below are measure in regard to crankshaft degrees [x2] ) GLT Intake:250dr duration 0.332 inch lift Exhaust:252,6dr duration 0.332 inch lift T5 Intake:242dr duration 0.312 inch lift Exhaust:243,5dr duration 0.312 inch lift" Would appreciate folks checking my math making sure I didn't typo... Thanks! Link to comment Share on other sites More sharing options...
scandalo Posted April 3, 2011 Report Share Posted April 3, 2011 IMGs are taking their sweet time to load. Anyone have any dyno numbers on this swap? I think that this is a great starting point for a sticky thread as I do not see much info on this floating around. Link to comment Share on other sites More sharing options...
Ipd Posted April 3, 2011 Author Report Share Posted April 3, 2011 I'll post them up on Ipd server tomorrow, for now they are on my server at home... As far as dyno numbers go, I haven't seen much. I've played with mine a bit on the dyno but before I did this work yesterday I was pretty much going by gut. At least now we have some data to work from. Link to comment Share on other sites More sharing options...
mdlimy Posted April 3, 2011 Report Share Posted April 3, 2011 nice! :tup: Link to comment Share on other sites More sharing options...
volvoskiah Posted April 3, 2011 Report Share Posted April 3, 2011 good work, that car is really well done. Link to comment Share on other sites More sharing options...
mdlimy Posted April 3, 2011 Report Share Posted April 3, 2011 good work, that car is really well done. nick choy's(NChoy) 6spd vr ;) Link to comment Share on other sites More sharing options...
854TGA+ Posted April 3, 2011 Report Share Posted April 3, 2011 What did the owner think of this mod? Did the owner notice any significant increase in power, or did it just move the power band around? Great documentation by the way! Link to comment Share on other sites More sharing options...
Ipd Posted April 3, 2011 Author Report Share Posted April 3, 2011 I haven't driven the car on the street yet and he hasn't picked it up yet, I'm sure I'll get more feedback this week. Robbie is correct, this is Nicks car. Link to comment Share on other sites More sharing options...
RobT5M Posted April 3, 2011 Report Share Posted April 3, 2011 Curious to see how it does vs before it was done. Thanks for this information Lucky since I will be doing this soon. Link to comment Share on other sites More sharing options...
lookforjoe Posted April 4, 2011 Report Share Posted April 4, 2011 I haven't driven the car on the street yet and he hasn't picked it up yet, I'm sure I'll get more feedback this week. Robbie is correct, this is Nicks car. I didn't realize you were working on the car when Nick called on Saturday Good info to have - esp since I need to move mine around to compensate for the modified intake :lol: Link to comment Share on other sites More sharing options...
andyb5 Posted April 4, 2011 Report Share Posted April 4, 2011 nick choy's(NChoy) 6spd vr :wub: Link to comment Share on other sites More sharing options...
the commissar! Posted April 5, 2011 Report Share Posted April 5, 2011 Lucky, why just the intake cam? and How would you set it up initially if you did intake and exhaust? (never mind...I see it now :monkey: Link to comment Share on other sites More sharing options...
lookforjoe Posted April 5, 2011 Report Share Posted April 5, 2011 Those pics are insanely large!!!! I just noticed that in your intake pic, it's actually only set around 2º retarded I set my int @ 4º retarded (exh 4º adv), and lost 2 inches of vacuum (dropped from 20 to 18). Link to comment Share on other sites More sharing options...
Ipd Posted April 5, 2011 Author Report Share Posted April 5, 2011 We did just the intake cam at this time since the turbo was sized such that it wouldn't need the additional duration the ex cam offered. Yeah, that pic was snapped before I actually locked everything down, noticed that later myself :lol: Link to comment Share on other sites More sharing options...
850wagonT5 Posted May 18, 2011 Report Share Posted May 18, 2011 So...here's a question for Lucky I guess? Let's say we wanted to have a "sport cam set" made. Something half way between stock cams and what you'd expect in a race car - common offerings for pretty much any sport compact on the market. What specs would you choose based on the stock Turbo cams as far as lift, duration, etc if you were getting cams re-ground to your own specifications? :huh: Link to comment Share on other sites More sharing options...
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