Cams or not to cams

[LouieMoo]

Hi guys I'm looking to do a set of cams on my terminator but I have 2 questions. 1. What cams do you think would go best with a KB2.8 and how much do the cams alone cost. 2. How much $$$ am I looking at for the install because I know this is a big job to do so I also want to know if it's worth it. Thanks guys any info will be greatly appreciated. P.S. Here is my before and after pics of making the car stock again.

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[Steve Cea]

Don't waste your money , cams are not cheap to either purchase or install nor will you get your money's worth in gains , gains will be minimal, you should be able to push near 700 hp with that 2.8 and a proper tune ! Cams in my opinion are a huge waste of money for what they cost , money better spent elsewhere!

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[LouieMoo]

Don't waste your money , cams are not cheap to either purchase or install nor will you get your money's worth in gains , gains will be minimal, you should be able to push near 700 hp with that 2.8 and a proper tune ! Cams in my opinion are a huge waste of money for what they cost , money better spent elsewhere!

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You know that was always a thought in the back of my head if it was worth it or not. Also the previous owners told me the car made 697hp but I haven't personally had it dynoed yet but since I recently had to change the throttle body I am in need of a tune so I will get to see the numbers myself. But I will say I did run 122mph in the 1/4 And that was with having to peddle 1st, 2nd and 3rd, so I know I lost some mph on that run. So hopefully I will get a read that I'll like. Thanks for the reply.

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[SlipperySnake]

Only worth it at 1000+


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[Aubz]

Only worth it at 1000+


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What he said. The main benefit from doing a set of cams is the sound. You have to be able to justify the money for the parts/install and realize that you're not going to gain a ton of power from it.

 

[SlipperySnake]

With aggressive turbo cams on a high boost application they are well worth it to increase the mass of air moving through the combustion chamber. They're worth 70hp give or take some on a race application. For a KB though save your money and go E85 much more beneficial.


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[GodStang]

Worth it is totally opinion based. If you are going to do it do it right. Custom cams for $1200ish, good springs are I think around $500, new gaskets, and shops charge $1500-$3000 depending on shop for just install.

On good setups you will loose boost and can add it back to pick up power. If engine is out I would for sure do them. Correctly degreed and correct for their setup guys have picked up 45-65rwhp over the years. A lot cheaper and easier ways to get that power.

 

[Black02GT]

Worth it is totally opinion based. If you are going to do it do it right. Custom cams for $1200ish, good springs are I think around $500, new gaskets, and shops charge $1500-$3000 depending on shop for just install.

On good setups you will loose boost and can add it back to pick up power. If engine is out I would for sure do them. Correctly degreed and correct for their setup guys have picked up 45-65rwhp over the years. A lot cheaper and easier ways to get that power.

I agree with GodStang, I couldn't see doing it if everything is working fine now. That being said I went with some custom cams when my engine was built mostly because I regretted not doing it on another build when it was apart. That plus it was just a bucket list thing to have a cammed car at some point and since it is just a weekend car now... (you can see I spent a little time justifying the cost to myself)

 

[c6zhombre]

I love the sound they create...even if the hp gains were zero. But the one thing I seem to see posted the most that alarms me about them is the increased IAT2s owners consistently report. These powerplants have enough issues fighting temps.

 

[tt335ci03cobra]

Sell the 2.8, buy a 2.9 whipple.

Doing heads and cams to a 2.9L whipple would be great, you'll barely notice the loss of low end torque. On a 2.8, which is already a little peaky, heads and cams would be noticeably softer down low.

Cam and head work is excellent. Let everyone talk shit on it. They don't understand how engines work. Our engines pick up loads of power and barely lose any drivability with even very aggressive h/c combos. I'm personally running a heavily ported ford gt/gt500 head with stage 3 MMR turbo cams and can comfortably drive at 1500-2000rpm. I'm turbo, but make 800whp on 11psi and pump gas. Most people have to run 15-18psi to make 800whp on pump gas with twin 62's for comparison.

On an sc setup you will drop 3-4psi with the same pulley combo and pick up 10-30whp give or take. Pulley back up to where you were and you have 50-75whp+. Keep it as it was pulleyed and you will notice it doesn't heat sink near as quickly. The compressor lobes or blades are still spinning just as fast but the engine flows the produced air much more efficiently and doesn't creat resistance or rather limit the flow.

Boost is a measure of resistance. If you can make the same power with less boost, your engine is more efficient and will last longer. There is less stress in the inner workings. This is all in the scope and scale of reasonable expectstions. We aren't comparing running a ridiculous cam and head combo. That would blow up quickly.

Cams and head work get a bad rap on our cars because 99/100 people haven't worked on an engine or understand what is going on in the engine.

If money is a hurdle, sell the 2.8, buy a 2.9 and be happy. Later, cam that combo and do some head work. You can get 800whp+ at about 20psi pretty easily with a cammed/head work 2.9, and about 750-800 out of the 2.8 in similar fashion but the 2.9 whipple will be much torquier.

That all said, the 2.8 with an aggressive head and cam may offer the perfect amount of torque production for a street car to hook. It won't be a centrifugal car by any means (very peaky/soft down low) so it will probably be great for the street. My turbo combo is intentionally "laggy" because I like to hook 1st and roll through 2nd. I'm a few hundred rpm shy of the exact spool characteristic I wanted but I'm also on a softer tune that is intentionally holding things back a little. That said I can launch in 1st and roll into 2nd without blowing the tires off, then 3rd and 4th work great. I'd imagine a 2.8 car with head and cam work running 3.90's or 3.73's and a 27-28" tire would be very usable hard charging top end and exploitable power.

Like any build, figure out what you want to definitely get as the end result and work towards that direction part by part without compromising just for time or convenience. When you get a car right and love everything about it, you'll find yourself doing things like putting 1000 miles on it in 2 weekends, or smiling just driving through traffic... ask me how I know haha.

 

[Gravik]

Pushrod engine? Worth it.

Modular? Not so much

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[tt335ci03cobra]

Beefcake picked up 41whp on an apten ported bolt on car. 480whp upto 521whp.


http://www.mustangandfords.com/how-to/engine/m5lp-0508-comp-cams-cobra-camshafts/

People that don't understand engines will always say cams don't work.

Let's see, the stock cams are something like 194/185 duration. 244/230 260/240 duration cams won't add any power. Nope. No way. It's snake oil.

It's expensive is what it is. But it works. Put some head work in and let it eat. A big supercharger is $5-7k, and takes our humble cobra's from 450whp to 650-750whp.

200-300whp for ~$6000. That's about $20-30 per hp.

Head cam combo is gonna run about $2500-3500 keeping c heads and going full tilt. It'll be worth 75-100whp if you pulley back for similar boost.

75-100whp for $2500-3500. That's about $25-45 per hp.

Also they picked up 60whp at the very high end of the graph. At like 6700, it was 440whp on the base line and 507whp.

That all said, a 2.9 whipple makes the most sense in the op's position. It's almost a free upgrade after selling the 2.8.

Save for very aggressive head and cam work afterwords. 750-800whp 2.9 car on 20-23psi.

 

[SVTdreamin04]

If you want to change how the car delivers power, then do the cams. It's your car, so do as you wish. I would suggest you read the articles from the past when the Cobra was the biggest talk of the day in the car world. There is plenty of info out there. I done a set of stage 2 comp cams because the engine was out of the car. Cams aren't a waste of money, they are just not as viable of a horsepower option as they would be on a pushrod engine.

But a cammed modular engine sounds so good!!!


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[MalcolmV8]

I've done multiple sets of cams in my car and re-degreed them different ways. Here's what I learned.

My initial reasoning was for the sound. I loved that choppy sounding idle. That turned out to be my big downfall while using a blower. I learned very painfully and the hard way that the boost bypass valve needs at least 13 ~ 14 inches of vacuum at idle to avoid drivability issues. Pulling off and driving becomes a headache otherwise, the car surges and jerks as the bypass valve closes with less vacuum. The rotors have to much air in them and it surges into the motor.

To get that nasty choppy sound you need overlap which kills vacuum. My car had a badass muscle car sounding idle but only 8" of vacuum at idle. It sucked to drive and I grew to hate the car. After consulting with "experts" I was lead to believe I had a duration issue and purchased more cams.

Long story short it had nothing to do with duration and I started degreeing cams myself and figuring it out for myself and a small amount of negative overlap goes along way. My idle vacuum came up to 14 inches of vacuum, the surging and jerking went away and the car drives and pulls off like stock. I have no IAT2 high temps or reversion issues at idle and part throttle cruise. Overall it's really cool. The downside? it doesn't have that crazy choppy idle I wanted in the first place when I set out on my quest for cams. Live and learn.

Now I've also tuned quite a few combos over the years and I can tell you without a bypass valve such as a centrifugal blower the overlap is not as big a deal. Also I've found guys with auto cars get away with a lot more because the converter absorbs the surging.

BTW expect to spend a good $1200 + for cams, another $400 or so in springs and retainers and then a few hundred more in adjustable cam gears and parts to degree them in correctly. If not doing yourself labor too, lots of it.

 

[GodStang]

You can not compare a Turbo/Centri Blower with Cams and a PD (eaton, Kenne Bell, Whipple) with cams. Two totally different things. Also not sure where you are getting your pricing but to take your stock heads and get the Stage III Port with a nice set of cams/springs you are looking at ~$4500 depending on options for just parts (Livernois, Fox Lake). labor is another $2K-$3K as the OP said he is not doing it himself.

We will go with your estimate 75-100whp as for all that I would say looks correct. Using your $$$/HP formula you are looking at a more realistic range of $65-$100 per hp.

Now if you get all the parts used and do it yourself then price will come down.

Is that worth it to the OP? I don't know.

Also selling a KB and buying basically the same size Whipple would net him next to nothing. It would also cost him about $1000 to buy new. unless he bought used not worth it. Trust me I just sold a polished KB 2.8L w/ less than 500 miles on it. I know what they go for.

Again it is his money and his car but he needs realistic prices/options if he really wants to go this way.

Beefcake picked up 41whp on an apten ported bolt on car. 480whp upto 521whp.


http://www.mustangandfords.com/how-to/engine/m5lp-0508-comp-cams-cobra-camshafts/

People that don't understand engines will always say cams don't work.

Let's see, the stock cams are something like 194/185 duration. 244/230 260/240 duration cams won't add any power. Nope. No way. It's snake oil.

It's expensive is what it is. But it works. Put some head work in and let it eat. A big supercharger is $5-7k, and takes our humble cobra's from 450whp to 650-750whp.

200-300whp for ~$6000. That's about $20-30 per hp.

Head cam combo is gonna run about $2500-3500 keeping c heads and going full tilt. It'll be worth 75-100whp if you pulley back for similar boost.

75-100whp for $2500-3500. That's about $25-45 per hp.

Also they picked up 60whp at the very high end of the graph. At like 6700, it was 440whp on the base line and 507whp.

View attachment 1409468View attachment 1409469

That all said, a 2.9 whipple makes the most sense in the op's position. It's almost a free upgrade after selling the 2.8.

Save for very aggressive head and cam work afterwords. 750-800whp 2.9 car on 20-23psi.

 

[black03]

The only time I'd do cams on a cobra is if I was going to have the heads done too. To just do the cams by themselves doesn't make sense due to the cost of them and the cost of installation. If you plan on getting the heads ported and valves done then do the cams at that point so you'll fully benefit from them.

We offer Comp, Crower and our most popular setup which are custom grinds from Bullet Racing. We can spec the cams out specific to your application depending on what you want and what your goals for the car are.

If you have any other questions please feel free to give us a call.

Thanks, Jared

 

[SVTdreamin04]

I've done multiple sets of cams in my car and re-degreed them different ways. Here's what I learned.

My initial reasoning was for the sound. I loved that choppy sounding idle. That turned out to be my big downfall while using a blower. I learned very painfully and the hard way that the boost bypass valve needs at least 13 ~ 14 inches of vacuum at idle to avoid drivability issues. Pulling off and driving becomes a headache otherwise, the car surges and jerks as the bypass valve closes with less vacuum. The rotors have to much air in them and it surges into the motor.

To get that nasty choppy sound you need overlap which kills vacuum. My car had a badass muscle car sounding idle but only 8" of vacuum at idle. It sucked to drive and I grew to hate the car. After consulting with "experts" I was lead to believe I had a duration issue and purchased more cams.

Long story short it had nothing to do with duration and I started degreeing cams myself and figuring it out for myself and a small amount of negative overlap goes along way. My idle vacuum came up to 14 inches of vacuum, the surging and jerking went away and the car drives and pulls off like stock. I have no IAT2 high temps or reversion issues at idle and part throttle cruise. Overall it's really cool. The downside? it doesn't have that crazy choppy idle I wanted in the first place when I set out on my quest for cams. Live and learn.

Now I've also tuned quite a few combos over the years and I can tell you without a bypass valve such as a centrifugal blower the overlap is not as big a deal. Also I've found guys with auto cars get away with a lot more because the converter absorbs the surging.

BTW expect to spend a good $1200 + for cams, another $400 or so in springs and retainers and then a few hundred more in adjustable cam gears and parts to degree them in correctly. If not doing yourself labor too, lots of it.

Just out of curiosity, did you try a low vacuum boost bypass valve?


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[MalcolmV8]

Just out of curiosity, did you try a low vacuum boost bypass valve?

Yes that keeps the bypass valve open at idle with low vacuum but it doesn't fix the surging or jerking that happens when the bypass valve closes.

In my testing a low pressure bypass valve takes about 3 ~ 4" of vacuum to hold it open.

The problem is when you're down to 3" of vacuum that's not very much of a vacuum at all and the rotors are filled with air. So when that valve closes there's a sudden surge or spike of air that's slammed into the motor as that happens. It can be observed on the wideband as well as felt by the driver. In normal cruise, even highway at times as you're slightly on and off the gas pedal and that valve is transitioning between open/closed the car surges and jerks.

I even tried slowing down the transition of the valve. I used nitrous jets in the vacuum / boost line going to the bypass valve actuator and that helped a lot. It smoothed out the driving a fair amount. It did not cure it but it made a big difference. However it had a massive side affect. When cruising along and then suddenly stabbing the throttle wide open there was a momentary delay for the power to come because the valve couldn't snap shut instantly due to the nitrous jet. It felt like the sort of momentary lag you can feel on a turbo car. I hated it. One of the things I love about the PD blowers is instant torque and power.

A stock bypass valve on the other hand is closer to 11" of vacuum to hold it open.

That's important because when the valve closes deeper in vacuum there's not much air in the rotors and you don't get a surge into the motor and its a smooth transition.

When I first started out I was running 8 degrees of overlap on my cams with a 110 ICL. It had a nasty idle and low idle / midrange vacuum and drove like crap.

I moved to smaller duration cams with not much luck. I then re-degreed them per the "expert" at 109 ICL with his LSA of 115 which gave me 0.5 degrees of overlap. Doesn't sound like much overlap but car still had poor idle vacuum and while it drove a tad better it seemed, it still drove horrible.

After talking to many people and doing my own research and info gathering and understanding I came up with my own center lines and LSA and ended up with just -4.5 degrees of negative overlap and wow what a massive improvement. I now had about 14" of vacuum at idle and was able to swap back in the stock bypass valve actuator instead of the low pressure one and the car drove like OEM. No bucking, jerking, surging or any of that junk. It idles solid and reliable and drives properly.

If you want to go with aftermarket cams I'd highly suggest getting in touch with someone that specializes in cams and knows these cars very well. Its not something you want your average joe moron spec'ing for you.

 

[s351]

I picked up 93 rwhp, with custom cams, and a 4 inch exhaust on my single turbo car on pump gas 94 octane. Car has a good chop to it, But one thing I will say drivability is good but it's not oem either. There is a price to pay not just $$ wise but streetability wise as well. There are little quirks when taking off too slowly or cruising really slowly, there is very very minor bucking.

If it was just about sound I would never do it, as much as I love my cars sound and idle, If i didn't gain a little rpm and power I would not of been happy. A nasty idle, pd blower, an street driving with these cars never ends well, from what i've read

I'm a turbo guy so we get away with a bit more than the pd blower guys when it comes to cams.

 

[SVTdreamin04]

MalcolmV8, thanks for the education!


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