Brian Crower cams on BPU?

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

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.

429 HP? I assume it was on 1,2 bar boost, right?

Stock rev-limiter?

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

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

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.

also bear in mind to get the MOSt out of HKS cams you will also need HKS cam pulleys

Why that ?

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

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.

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 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.

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

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.

And what if you replace the Valva springs?

Is the bottom end the bottle neck in terms of high revs?

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.

The general result of fitting higher lift/longer duration cams is to drive the peak torque and power delivery higher up the RPM scale.

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.

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

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

Duration at ??? lift is the critical and comparable figure though. And that is what is a variable across makers.

I have the cams from Paul Whiffin... I was impresses with the results!

264 9.3mm

What is your setup mate?

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