RedT18 Posted September 21, 2010 Share Posted September 21, 2010 Hey Guys, just wanna know if anyone of you has apair of BC cams on a BPU Supra? I am wondering what effect they will bring with the stock Turbos. Does it make sense? What is the idle with 264° resp. 272° cams? How much revs can the stock bottom end handle? Any experience, then post it Thank you Quote Link to comment Share on other sites More sharing options...
Nic Posted September 21, 2010 Share Posted September 21, 2010 I use to run in256/ex264 cams on mine with the stock turbos and Emanage, you notice a little more mid to top end power, car made 429hp. It doesn't make a huge difference but it is noticeable. Idle was fine, no difference. Quote Link to comment Share on other sites More sharing options...
RedT18 Posted September 21, 2010 Author Share Posted September 21, 2010 429 HP? I assume it was on 1,2 bar boost, right? Stock rev-limiter? Quote Link to comment Share on other sites More sharing options...
Nic Posted September 21, 2010 Share Posted September 21, 2010 429 HP? I assume it was on 1,2 bar boost, right? Stock rev-limiter? 1.2bar Stock rev limit. Turbos running in parallel Emanage HKS Cams in256/ex264 680cc injectors Quote Link to comment Share on other sites More sharing options...
jevansio Posted September 21, 2010 Share Posted September 21, 2010 You need to be aware that HKS cams at 9.3mm do not make an interference engine, where as the other makes with their higher lift do (depending on setup). This means its advisable to upgrade the timing tensioner setup as well as valve train upgrades. HKS actually recommend valve spring upgrades for the 264 cams although not a lot of people follow this and only upgrade when going to 272s. For BPU level I would stick with HKS cams Quote Link to comment Share on other sites More sharing options...
Jamesy Posted September 21, 2010 Share Posted September 21, 2010 also bear in mind to get the MOSt out of HKS cams you will also need HKS cam pulleys i would only do it on a BPU car if i was planing on doing a single conversion at some point. Quote Link to comment Share on other sites More sharing options...
Luxluc Posted September 21, 2010 Share Posted September 21, 2010 also bear in mind to get the MOSt out of HKS cams you will also need HKS cam pulleys Why that ? Quote Link to comment Share on other sites More sharing options...
Jamesy Posted September 21, 2010 Share Posted September 21, 2010 Why that ? when going for the more agressive cams - like 269, 272 etc .... you need to time them in via the pulleys to make them most efficient. you can just whack a set in, but i'd prefer to have them working to their best ability and being timed in properly Quote Link to comment Share on other sites More sharing options...
Luxluc Posted September 21, 2010 Share Posted September 21, 2010 when going for the more agressive cams - like 269, 272 etc .... you need to time them in via the pulleys to make them most efficient. you can just whack a set in, but i'd prefer to have them working to their best ability and being timed in properly Got that. I have my HKS 264 cams, and Darren (at Whifbitz) told me that timing on 264 wouldn't be necessary (not bring much) on the Supra. So I guess aftermarked pulleys are interesting when going for 269+ cams. Quote Link to comment Share on other sites More sharing options...
RedT18 Posted September 21, 2010 Author Share Posted September 21, 2010 And that's exactly my plan The questions is, if it maikes sense to lift up the rev limiter (E-manage). Does anyone of you have a Dyno plot? I wonder how the max. torque will shift. Quote Link to comment Share on other sites More sharing options...
Jamesy Posted September 21, 2010 Share Posted September 21, 2010 you can go to 7250rpm on a stock bottom end as thats what the VVTI's run at. Depeneding on supporting mods you can go to 7500rpm....after that i'd go for a built engine mate. Quote Link to comment Share on other sites More sharing options...
Jamesy Posted September 21, 2010 Share Posted September 21, 2010 Got that. I have my HKS 264 cams, and Darren (at Whifbitz) told me that timing on 264 wouldn't be necessary (not bring much) on the Supra. So I guess aftermarked pulleys are interesting when going for 269+ cams. Yeah i think 264 are more of a direct drop in. My cams are the equivilant to a 269 with a 9.9 high lift so we had to go with the pulleys to get the most out of them Quote Link to comment Share on other sites More sharing options...
Nic Posted September 21, 2010 Share Posted September 21, 2010 And that's exactly my plan The questions is, if it maikes sense to lift up the rev limiter (E-manage). Does anyone of you have a Dyno plot? I wonder how the max. torque will shift. You do lose a little torque lower down in the rev range, you feel the difference when the 2nd turbo comes in, it pulls harder and longer with the in256/ex264 cams peak power was around 6K rpm. Quote Link to comment Share on other sites More sharing options...
RedT18 Posted September 21, 2010 Author Share Posted September 21, 2010 And what if you replace the Valva springs? Is the bottom end the bottle neck in terms of high revs? Quote Link to comment Share on other sites More sharing options...
Luxluc Posted September 21, 2010 Share Posted September 21, 2010 How much revs can the stock bottom end handle? Mappers don't push a stock engine above 7.2k. Unless you have a big turbo and wild cams, no real need to go higher nevertheless. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted September 21, 2010 Share Posted September 21, 2010 The general result of fitting higher lift/longer duration cams is to drive the peak torque and power delivery higher up the RPM scale. Quote Link to comment Share on other sites More sharing options...
RedT18 Posted September 21, 2010 Author Share Posted September 21, 2010 Thanks for the answers. The question is not if it makes sense to rev higher than the stock rev limit, the question is what can the stock BOTTOM end handle. let's assume we have 272° cams and the necessary springs and so on. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted September 21, 2010 Share Posted September 21, 2010 Are you measuring duration like for like? The Yanks measure duration at a different lift to most Japanese and European makers, which may explain why some Yank cams in a VVTi seemed to give very off power curves. They really need to go on a cam measuring rig alongside HKS to see what's happening. This is a proper spec card that you get from running a cam on an Auditech machine, they are from my turbo 1.6 Toyota engine. You can see you get proper specs like this: -------------------------------------------------------------------------------- CAM PRO PLUS Cam Card Report 10:25:22 21/09/2010 -------------------------------------------------------------------------------- Spec. Value ---------------- ----------------------------------------- File *************************** Lobes I1 Lobe Separation ----- Cam Deg. Checking Height 0.25 mm Valve Overlap ----- Crank Deg. Intake Exhaust ------------------- ------------------- Centerline 106.0 ATDC Open 51.4 BTDC Close 92.6 ABDC Duration 324.1 Crank Deg. Area 1042.8 mm Deg. Lash 0.250 mm Rocker Ratio 1.00 Peak Cam Lift 11.3120 mm Peak Valve Lift 11.0620 mm Lift @ TDC 4.394 mm ------------------------------------------------------------- Spec. Value ---------------- ----------------------------------------- Checking Height 1.00 mm Valve Overlap ----- Crank Deg. Intake Exhaust ------------------- ------------------- Centerline 106.0 ATDC Open 32.2 BTDC Close 65.9 ABDC Duration 278.1 Crank Deg. Area 1031.1 mm Deg. Lash 0.250 mm Rocker Ratio 1.00 Peak Cam Lift 11.3120 mm Peak Valve Lift 11.0620 mm Lift @ TDC 4.394 mm ------------------------------------------------------------- Spec. Value ---------------- ----------------------------------------- Checking Height 1.25 mm Valve Overlap ----- Crank Deg. Intake Exhaust ------------------- ------------------- Centerline 106.0 ATDC Open 29.0 BTDC Close 62.2 ABDC Duration 271.2 Crank Deg. Area 1027.2 mm Deg. Lash 0.250 mm Rocker Ratio 1.00 Peak Cam Lift 11.3120 mm Peak Valve Lift 11.0620 mm Lift @ TDC 4.394 mm Quote Link to comment Share on other sites More sharing options...
Nic Posted September 21, 2010 Share Posted September 21, 2010 These are stock cam figures for reference J-spec 2JZ-GTE Intake Duration 224° Intake Camshaft lift 7.88mm Intake valve diameter 33.5mm Intake Valve timing - Opening 3° BTDC Intake Valve timing - Closing 50° ABDC Exhaust Duration 233° Exhaust valve diameter 29mm Exhaust Camshaft lift 8.4mm Exhaust Valve timing - Opening 52° BBDC Exhaust Valve timing - Closing 4° ATDC UK Spec 2JZ-GTE Intake Duration 233° Intake Camshaft lift 8.25mm Intake valve diameter 33.5mm Intake Valve timing - Opening 3° BTDC Intake Valve timing - Closing 50° ABDC Exhaust Duration 233° Exhaust Camshaft lift 8.4mm Exhaust Valve diameter 29mm Exhaust Valve timing - Opening 52° BBDC Exhaust Valve timing - Closing 4° ATDC Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted September 21, 2010 Share Posted September 21, 2010 Duration at ??? lift is the critical and comparable figure though. And that is what is a variable across makers. Quote Link to comment Share on other sites More sharing options...
a98pmalcolm Posted September 21, 2010 Share Posted September 21, 2010 I have the cams from Paul Whiffin... I was impresses with the results! 264 9.3mm Quote Link to comment Share on other sites More sharing options...
RedT18 Posted September 22, 2010 Author Share Posted September 22, 2010 What is your setup mate? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted September 22, 2010 Share Posted September 22, 2010 This explains why the figures bandied about Jap car sites are meaningless, I plagiarised it from Cat Cams UK site to save me having to make my own effort to explain it in depth : Cam Durations What is the duration at 1mm? Whenever a duration is quoted it needs to have the checking height (how far the valve is open) listed for the numbers to be of any use. The more commonly quoted 'Seat to Seat' durations also include the opening and closing ramps of the camshaft. Below 1mm of valve lift there is very little effectively happening. The valve is still moving relatively slowly and the valves are flowing very little. Because of these factors its much more useful to look at the duration of the camshaft once the opening/closing ramps have been taken out of the equation.Using the metric system these are quoted at 0.1mm for seat to seat duration and 1mm. This best way to see what is happening to look at a couple of Cam profiles: 1321806 1321816 [email protected] + Valve clearance 300° 299° Valve lift (clearance=0) 12.95mm 13.00mm Using this checking height and valve lift, the profiles look to be very similar and you would expect very similar performance from them. If we now add the durations at 1mm then we get the full picture: 1321806 1321816 [email protected] + Valve clearance 300° 299° [email protected] + Valve clearance 263° 274° Valve lift (clearance=0) 12.95mm 13.00mm Now it becomes clear that the 1321816 profile has 11 degrees more duration at 1mm checking height. This is what the engine sees in terms of airflow and makes this cam much wilder than the 1321806. When you extend the cam duration on an engine there is always a trade off between low/midrange torque and top end power (and its often not a fair trade off, you tend to lose a big chunk of low rpm tractability for a smaller gain at the top end). Whats needed is to keep the duration as short as possible but get the valve opening very quickly to a higher lift where the head flows better. This is the basic trend of Catcams Short duration/high lift profiles and the nett result is higher torque figures and wider powerbands. If you are trying to compare our profiles to other manufacturers, please not that our Seat (0.1mm) durations are often a lot smaller, however the agressive nature of Catcams profiles means the Duration @1.0mm is often significantly higher. The only real way to start to compare profiles is to ask for the duration @ 1.0mm Quote Link to comment Share on other sites More sharing options...
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