How to Choose Your Cam.. Duration, Overlap and more.

Choosing performance cams can often seem like a difficult task for many, considering the many variables that can apply to any one camshaft profile or application. I’ve seen too many cars with the wrong cam profile struggle on the dyno or even worse make their owners struggle with just driving.

Before choosing a cam however, don’t forget to remember what you are choosing the cam for; drag racing? road racing? any daily driver usage?

 

Let’s begin by tackling each term and what it means.

What is valve lift?

How far the cam opens the valves, when increasing lift you increase the length the valve opens, which will produce positive gains in airflow. Be careful when selecting your cam, as too much lift may cause valve float as you will see many manufacturers list recommendations for upgraded springs, retainers or guides.

What is duration?

The amount of time that a valve is open, regardless of intake or exhaust and measured in degrees of crankshaft rotation for that period. What does this mean to you? It tells you what the cam’s potential is within a specific rpm range. Shorter duration cams provide low end torque, while longer duration cams allow for more top end flow.

For all the SOHC ninjas :)

What is overlap?

The amount of time that both exhaust and intake valves are open in any one cylinder at the same time. Usually this is close to Top Dead Center as the piston stroke begins down the bore and the exhaust valves must stay open until the piston pushed the gases out.

 

What is timing?

Enthusiasts most commonly mistake this term “timing” to ignition timing when it comes to valvetrain events. Trust me, this happens way too often to make any sense.

What is camshaft timing? It’s what you can adjust when you have an adjustible cam gear, that will allow you to alter the timing events.

When you advance the camshaft timing, you are making the intake valve open sooner which will give you more low end torque. As always, when advancing or retarding the camshaft timing you must be conscious of the safety window in piston-valve clearance as to avoid a “catastrophic” event.

Retarding the camshaft timing will delay the intake closing and keeps the intake valve open for longer. This is one of the oldest tricks in the book for turbo Eclipses, Talons and Lasers in the mid-90s by selecting just one exhaust cam and retarding it to -5.

EPSON DSC picture

By retarding the one exhaust cam you could sacrifice idle quality for some terrific top end by holding the intake valve open to move the overlap higher in the powerband.

This is a shot of my old 1999 Mitsubishi Eclipse Spyder, before AWD conversion, retarded negative -5 on the exhaust cam and putting down 395 to the wheels @ 22 psi on 91 octane, extremely reliable.

Of course in today’s age of variable valve timing in everything, many of these older tricks are not needed to generate huge amounts of power without sacrificing idle and start response. In the mid 90s however, you weren’t doing that unless you had a turbo VTEC motor, which had it’s own set of problems in that era.

Increasing the duration is increasing the amount of time the valve is open, therefore helping the engine effectively fill the cylinders and produce power. Many camshaft profiles maximize flow by opening the exhaust cam extremely early in the cycle, increasing exhaust output and increasing the exhaust valve fully open when the exhaust stroke begins. During the power stroke, the burning fuel has used about 80 percent of its available force on the piston by the time the crank has turned 90 degrees.

The bottom half of the power stroke actually provides very little in terms of engine power, and it can be better used to help exhaust the combustion chamber so that there is more efficient cylinder filling on the intake stroke.

Meanwhile a more aggressive profile with higher lift velocities will shorten the duration which will help power, but narrow the powerband.

What is LSA?

Lobe separation angle is the number of degrees between the centerlines of the intake and exhaust lobes on any one cam. The lower the LSA, the more overlap you create while increasing the separation decreases overlap.

Remember to avoid the most common mistake, and that’s going with the most aggressive cam available only because “It sounds so badass” An overly aggressive long duration cam may sound cool at idle, but will give you a very top heavy and small window of power in the rpm range.

Add to that equation the idle, emissions and starting issues, and you can quickly see how a mistake in cam selection can ruin your enjoyment with your car. Which isn’t the point… right?

In the end, choosing a cam that’s right for you is a big part of your performance equation. If you have any more questions, feel free to shoot me an email or post below! As always, if in doubt ask your nearby tuner in your area!

Happy shopping!

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Everybody was KUNG FU FIGHTIN!!!!

stockspyder:

The words Mitsubishi Evolution and Jackie Chan go hand in hand, if you have watched any of his movies and many of the car scenes.

Reblogged from Bob’s Your Uncle, this fresh set of Jackie Chan modifications that are custom tailored for the Evo IV and V. Enjoy!

Originally posted on BobsYrUncle:

Firesports by Jackie Chan? I knew he was into cars like the Evo IV and V from some posts I’ve seen a long time ago but never knew he was into design and making parts. WOW Jackie Chan! Nice to see there’s real car enthusiasts that are into the scene and supporting it. http://img399.imageshack.us/img399/8421/42513978sq.jpg

http://img399.imageshack.us/img399/3585/42513989ei.jpghttp://img399.imageshack.us/img399/7429/42513954jf.jpghttp://img399.imageshack.us/img399/5991/42514070cw.jpghttp://img399.imageshack.us/img399/7840/42514069sl.jpghttp://img381.imageshack.us/img381/7053/42514084jd.jpg

Here’s the man himself in one of his Evo

http://img381.imageshack.us/img381/6352/42513938zq.jpg

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SRT-4 Civic? Say it isn’t so……

Civics are funny cars.

Most will garner negative responses from people, the occasional “ricer” or other obligatory insult, usually uttered by those ignorant of Honda’s rich racing tradition or what Honda has done for automotive enthusiasts for the last 2 decades.

But they are also some of the coolest machines on the road ( well, at least for me ) and I for one love Hondas for their cheap price, light weight and an excellent choice of modifications.

So it’s not everyday when I see a motor swap in a Civic that makes me scratch my head. And that’s what makes this Civic so special?

Yes, that’s a SRT-4 engine stuffed into a EG!! I can hear Honda fan boys gasping in shock all across the world!

If you can get over the obvious Honda – Dodge hate, it’s clear to see why this is a cool choice. Cool gimmicks such as oil squirters, oversized diameter valves and seats, exhaust valves made of Inconel and a larger displacement are all great upgrades over the usual GSR or K series swap.

440hp / 424 ft lbs of tq from one unique swap.

Happy boosting!

Project Fit – Hondata’s New Flashpro

Well, it’s been a long time waiting for our 2008 Project Fit Sport, and with dreams of turbo whooshes, we’ve finally received our Hondata FlashPro. Our FlashPro is part number FP-FIT-US-120001, (yep number one baby!) and after our supporting turbo mods, we are ready to install the FlashPro and start tuning!

Newest changes to the FlashPro as it pertains to our Honda Fit are :

  • Added support for the 2012 Civic Si, 2013 ILX, 2007-2008 Fit.
  • [Traction Control] Firmware 6
  • FlashPro firmware updated to version 47
  • [Civic Si / Type R] Added learned fuel trim under closed loop parameters

After flashing the unit, we are ready for install and setup of the most basic parameters. I will outline a few of the settings we’ll be adjusting. As this Fit is still a daily driver, we’ll be aiming to retain it’s factory emissions and gas mileage without disrupting how the car drives or feels on the road.

To do this, we’ll be looking at tuning the Fit in closed loop mode while referencing the “closed loop target lambda” table in the FlashPro.

This controls the target lambda (air/fuel ratio) when the vehicle is running in closed loop. A combination of tables is used the set the target lambda, based on temperature and load.

Next up : Trying to squeeze as much power and torque from the engine stock as possible, before slapping on our turbo kit and going for broke.

Happy tuning!

Case Studies : Apexi Super AFC Wiring Diagram : How to install a AFC.

While the age of the piggyback computer is slowly coming to an end, many enthusiasts would be remiss to overlook the benefits of adding a piggyback such as the Super AFC to their vehicle for tuning flexibility.

So people have been asking for diagrams and sending questions regarding the APEXi SAFC unit. I have included a scanned image displaying the wiring diagram and how to install steps below :

And here are a few links to previous Case Studies where we install the AFC and tune it.

Installing SAFC into a MKIV Supra

Installing SAFC into a Dodge SRT-4

Tuning SAFC – How to tune your car for dummies

Happy tuning!

 

Project SC : 2JZGTE ECU Wiring into SC300 Guide

To prep the SC for the GTE swap, I’ve sourced a MT GTE ECU and a Aristo ( JDM 2JZGTE ) engine harness. For those doing this swap into a SC300, the wiring is a lot easier than the typical S-Chassis wiring in that many of the vehicle’s functions and wires are the same.

Given the similarities between the SC300 and the MKIV Supra, this is really no surprise, however you will need to lengthen and extend the third plug or body plug as well as rewire.

This body plug disconnects from the sc300 along the firewall, next to the ABS module and near the windshield.

Upon splicing open this harness, you will notice many similarities with your Aristo harness.  The large connector on this harness connects to the SC300 body plug and also the small plug that leads to the ECU.

For ease of wiring installation, we are eliminating the following wires (Traction Control D17,  Pressure sender ( Dummy Light ) D10, and Transmission Shift indicator D1)

Use the following pinout and match the corresponding colors accordingly.

courtesy of clublexus.com. not my pic

The Aristo harness and ecu plugs :

For a pin by pin how to, refer to this chart here :

Now with your engine harness properly wired, you may now remove your old SC300 harness and install your GTE ECU and plug it in. Next up, we start yanking weight in preparation of motor swap, as well as installing a new Cometic head gasket, ARP head studs and selecting our turbo setup.

Happy boosting!

Project SC : A New Beginning… Or is it?

I have to admit that moving from the nimble and athletic S14 chassis to a heavy pig like the  Z30 ( or Soarer if you are in Japan ), hasn’t been an easy transition for me.

It’s taken some time, but the comfort of the SC300 and overall finish make for an excellent street car and comfortable cruiser. However the issue of curb weight / power to the wheels is still undeniably present, but nothing a 2JZGTE swap won’t fix.

First however, I’ve got to ditch the belt driven fan assembly, because…. well…. it’s stupid. Not only does it constantly spin and create a drag on the rotating assembly, but its freakishly huge and bulky, taking away precious engine compartment space.

Upgrading to a slimline fan assembly

We’ll be using a Mishimoto fan shroud, and 2 12 inch dual speed fans for A/C connectivity ( California is hot! ) as well as a fan controller for maximum reliability.

This will be replacing this honking huge piece of crap.

For a fan controller, I personally love the Derale lineup of controllers which feature a safety bypass, dual speed control as well as your choice of probes and temp senders.

For this install, I have opted for the push in style of connector for ease of install. Why? well the 2JZGTE is a very high temp motor, and given the turbocharged nature of this motor cooling is of the utmost importance, especially on a daily driver.

However a true 3 core radiator is not in stock currently from Mishimoto or Fluidyne, two of my favorite radiator companies. So for the meantime, we’ll be rocking this push in style sender until our permanent radiator arrives.

This install is berry berry easy sir.

First we crack the 12mm nuts on the fan assembly, while keeping the tensioner tight on the belt itself. There are 4 10 mm bolts that hold the shroud in place, you may or may not need to remove your factory battery to remove the shroud.

Once these have been loosened, then undo the tension by turning the belt tensioner clockwise. Slip the accessory belt over the pulley and then proceed to carefully remove your factory fan and shroud.

Install of the new assembly is very straightforward, outside of a fabricated driver side mount.

After wiring in the ground to the Derale relay, we start up the SC and get it to operating temps very quickly. The slimline fan not only makes the engine bay look more clean and organized, but gives me at least 5 more inches to move and wiggle when the GTE motor is ready to go in.

I also ditched my Stern ST7’s for another set of Stern wheels, this time in 19 inch and ST11. With 19×8.5 in front and a 25 offset with 19×9.5 in rear with a 30 offset gives me a good stance and is cheap enough so that I won’t cry when a rim bends due to California highways.

Not really looking to change much more of the looks about the car until after my motor swap is completed. Lots of work on that front so I’ll be busy no doubt there.

First however, I’ve got to prep the wiring for the GTE swap, which means lots of wires and a lot of cursing. Fun.

Next up : Wiring up the 2JZ engine harness and combining with the SC300 body plug for a true plug and play installation.

Happy boosting!

Case Studies : Clocking a Turbo

After my diagnosis on the CT26 turbocharger, I’ve determined that the best path would be to service and sell the turbo, rather than put it on the 2JZ as a starter kit.

To do this and get the maximum return however, I’ve decided to just sell as a replacement MKIII Supra turbo. Problem is, the CT26 I have now is not clocked correctly for a 7MGTE motor, and the compressor housing just isn’t the correct outlet or shape.

While this CT26 is being sold, this method can be used to rotate any turbo or service any center cartridge when the need arises. While the need may not arise, there may come a time when a new intercooler, different feed and return lines or other details may dictate a new turbo orientation.

First we must remove the old compressor housing, install the new one and clock the center cartridge so that the oil lines match up and charge piping mates to the turbo.

Using a needle nose and a small flathead, you must first loosen the tension in the circlip holding the compressor housing to the CHRA.

Now, undoing the compressor housing will give you a full view of the compressor wheel, make sure to not damage the outer ring when installing the replacement compressor housing.

Now last but not least, you must rotate and loosen the bolts / circlip holding the exhaust housing to the hot side of the turbo. Installing the new compressor housing and moving the internal wastegate mounts and arm over are the final steps.

Make sure to line up and adjust the wastegate actuator, so that there is no excess slack or tension in the rod before installing into your car.

Happy boosting!

Project SRT-4 : Back on the road and tuning with the AFC

Project SRT-4 has been on a long hiatus, and after popping the headgasket late in 2008, we’ve finally gotten back around to getting this monster back on the street. Since it’s been a few weeks since our last update, let’s run through a quick recap.

Staying with the stock bottom end, we’ve chosen to run a Cometic head gasket for the SRT-4 along with ARP head studs to keep the 2 halves together.

Head is assembled, cams and cam caps torqued and assembly lube generously applied. Next, we torque down the head, following the SRT-4 tightening sequence.

Now onto the real challenge, installing and fabricating the downpipe, chargepipe and turbo kit on the back of this motor. What you are looking at is a 50mm Tial wastegate, DNP Turbo manifold and the back of the motor.

Project SRT cracked 350 whp on my Dynojet448x using a slightly upgraded stock turbo and stock fuel. Since then, we’ve stepped up to a 62-1 Garrett T3/T4 turbocharger in hopes of chasing down 440 whp on 91 octane.

Unfortunately, that also means ditching the stock manifold, turbo and downpipe, and if you’ve ever seen the SRT-4 Engine bay, you know how much of a bitch this is going to be.

After quite a bit of cursing and yelling, we’ve mounted and installed the turbo, manifold and wastegate, but our problem is still the dumptube.

Here’s a shot of under the car, looking at the back of the motor between the firewall and subframe. If you see the 2 power steering lines going into the rack there, that is about the only space we have to route a dumptube.

Time to get lucky.

Using a Vibrant V-band flange, we weld a 1.75 inch J pipe and completely hack up the bend to get the radius as tight as humanly possible.

After a lot of cutting and hacking, we’ve got a pipe that allows us to bolt it to the wastegate egress, but the bend is not tight enough to clear the power steering lines or alternator properly. Further, the opening is not large enough for us to cut and reweld, and instead of removing parts again, we’ve opted to heat up the pipe and bend as need be.

Unfortunately, we forget that the dump tube is 304 stainless.

It look a whole lot of heating and bending, but we finally got the screamer pipe to bolt on and clear all the lines properly.

A look at the finished product, note the clearance on the power steering lines as well as the clearance to the charge pipe coming off the turbo.

Now with that out of the way, we go to tune the SRT-4, only to find that the AFC NEO has a blank screen and refuses to turn on. This is a fairly common issue for these piggybacks as people love to yank and pull on the wiring loom, pulling the daughter board out of the AFC PCM.

To fix this issue, simply remove the hex bolts on the back of the AFC NEO and gently pull apart.

After plugging the harnesses back into the daughterboard, we snap the NEO back together and reinstall the hex bolts.

Your NEO may or may not go into DEMO mode, a mode in which the screen flashes and is not responsive to any button inputs. To solve this issue, turn the car off and then turn it back on while holding the UP button on your NEO.

This will force it into a diagnostic mode, where you must select to “reset” the NEO to gain control of it again.

After all the little BS issues are taken care of, we dial in the boost at a very low 10 psi and hit the streets with a datalogger to get some rough tuning out of the way.

Next up?

Dyno time for the SRT-4 as we chase 400hp on 91 octane.

Happy boosting!

Project SC : A new beginning

Well, maybe not a NEW beginning, but Project 2JZ-240SX has certainly taken a turn as the S14 undergoes surgery, I begin tearing into my new whip, a 92 manual SC300.

The car is monstrously heavy compared to the S14, and with the blown shocks and other Mickey Mouse work done to the SC, it rides like a boat.

Response is dull, steering feedback is lacking, and the car plows into every corner, pushing until the limit, when at long last I can bring the heavy rear end of the car around. Sadly the car doesn’t have enough steering angle to compensate, and the heavy nature of the car makes it difficult to step out as easily as the S14 did.

Compared to the athletic and nimble S14, it’s clear what the SC will become, a nice street car with a 2JZ swap in it. I am considering BAR legality currently, to see if it’s worth the hassle of legalizing the motor upon swapping into my SC.

The paint on the car is in decent shape, the tan interior is very clean, albeit ugly as sin. I make plans on picking up black interior, but first I’ve got to address some issues with the car, such as the headlights not working or the starter working.

Upon further inspection, it seems as though the driver side harness has been chewed up due to be lowered.

It shocks me that to this day, people still aggressively lower their cars down without considering the engine harness.

First, undo the 2 10mm bolts holding the engine harness to the frame, these are located toward the rear of the driver side fender well.

Taking these 2 10mm bolts out will allow you to pull *GENTLY* on the harness and give you enough slack to push the harness up and out of the way. Secure it with zipties or metal loops, I’ve opted for McMaster Carr ground straps.

After I’ve re-run the harness, I take apart the harness to repair the wires that had been run through and damaged. Now wrap up the harness and tuck it away, make sure to give yourself plenty of clearance so that your rims and tires don’t touch the harness ever again.

Next up, I tackle the tan interior of the SC300.

It’s clean.. .but too…….. tan.

You must undo the shift bezel, undo the screws that hold the center console in, and pop out the entire center console panel allowing you access to the radio and climate control mounting bolts.

After undoing those bolts, now remove the climate control and radio as a whole to give you access to the rear screws and dash vents.

I also decided to move over the MOMO Race wheel, because deep dish is so much more nicer and should go into my S14, which is dedicated track only use now.

With the new black panels installed, the car looks much better but the tan seats and carpet are still an eyesore.

Next up, getting rid of the stock seats, carpet, and putting the SC on a diet.

Happy boosting!