I'm contemplating on what cam to use. I'd like to build the engine up to get the most out of the turbo but still have bottom end torque. I'm planning on 8.3:1 comp. I'v looked at mikes cams and the smallest cam is 262, which seems too big to me, I was looking thru Schniders catalog and they have a 210/210 cam, and Comp has a 252 cam. which 1 of the cams would work best?
Turbo cam help
- Thread starter matt1967
- Start date
StrangeRanger":3cgzdir0 said:
Found it, thanks. did not know Isky made cams for the small 6's
Guess your talking about the turbocharger cam. now that's listed for a 1.6 rocker ratio, IF I use my stock 1.5 rockers, will it make much of a diffrence as to performance, I know it would make the cam smaller in a way. also, it says up to 7 PSI of boost, would it hurt to run that at 8-10 PSI?
With the lower ratio rockers, you'll need more cam.
With more boost you'll need more cam.
What you do not need is more overlap. Look for a 112° or even a 114° LCA with fairly short durations and as much lift as you can get. Consider swapping to the 1.6 rockers. You get 6.7% more lift at the valve with the same lift at the cam
With more boost you'll need more cam.
What you do not need is more overlap. Look for a 112° or even a 114° LCA with fairly short durations and as much lift as you can get. Consider swapping to the 1.6 rockers. You get 6.7% more lift at the valve with the same lift at the cam
StrangeRanger":171y06x2 said:
by fairily short dururations, how short do you mean? this schnider cam work good?
13720
256H
256
256
204
204
.420â€
.420â€
112
.000â€
.000â€
43795
as for the 1.6 rockers, at the very least I think I'm going to go with the stock type adjustable, but for only a little bit more, I could get the roller tipped rockers.
Mustang Boy
Well-known member
i dont think u need a cam that small cause does10s is using a 272 duration cam if i remember correctly with i think like 12lbs of boost and made ~450 ftlbs of torque at 2500RPMS
Yep, its always good to get a wide lobe cam if you can, to give the car less overlap. However, that is of less importance in an I6 than it is with a car with no torque like an OHC Ford four cylinder.
You can't really over cam a Ford I6. The stock cam at hydraulic valve lash (4 thou) is just a 252 or 256 total degree joke, with less than 185 degrees of lift at 50 thou lift. There is very little exhast coming out of the engine, and very little air/fuel mix going in, so anything below 260 degrees is a waste of a good camshaft grind.
A cam around 264 to 272 is ideal. It may have about 200 degrees duration at 50 thou lift. Sizes up to 272 is about the limit on the street due to pre boost surging.
Generally, going up in duration is just what you need. The effective compression of a 272 degree cam with, say, 205 to 208 degrees of duration at 50 thou open is still going to work fine with 8:1 compression.
Technically, the only important figures for the cam ar not total duration, or duration at 50 thou, but duration at 30 thou valve lift. Most aftermarket cams have an aggressive ramp, and have less duration at 20 thou than the stock cams. So technically, a 264 or 272 cam will have a similar low speed character to the stock 252 or 256 Ford cam.
Turbos respond to the same good gear normally aspirated cars do. The only problem is running into surge at off turbo (before full boost) with a bigger cam bigger than 280 degrees at lash. At low speed, there isn't the stable air flow there is with a 252/256/264 or 272 degree cam.
David Vizard had a great situation where a little low compression 2.0 Pinto engine got a something like small 272 degree Isky 134 cam, and then went to a bigger 280 cam and got a great improvement in power and torque with one of his customers turbo engines, an improvement everywhere. The 134 Isky cam had less duration at 50 thou than the stock 268 degree Ford OHC cam!
Other OHC Pinto engine builders he worked with found that over 300 degrees, its very easy to over cam the engine and get into a surge zone. Peak power still gains, but then there is a low down, low speed drivablity problem. It cannot be fixed by sizing the turbo up or down, and results in all kinds of issues.
The summary will be the same with a 200 I6 as with a 2.0 Pinto engine. You can't over cam it if its below 272 degrees.
If your car has a poor breathing head, its okay to go for a wilder cam. The Aussie X-flow headed 250 ran factory cams of up to 264 degrees with a free flowing head, and the car was very tractable with 8.7 to 8.8:1 compression.
It's hard to imagine a 272 degree cam ever having problems in a 200.
You can't really over cam a Ford I6. The stock cam at hydraulic valve lash (4 thou) is just a 252 or 256 total degree joke, with less than 185 degrees of lift at 50 thou lift. There is very little exhast coming out of the engine, and very little air/fuel mix going in, so anything below 260 degrees is a waste of a good camshaft grind.
A cam around 264 to 272 is ideal. It may have about 200 degrees duration at 50 thou lift. Sizes up to 272 is about the limit on the street due to pre boost surging.
Generally, going up in duration is just what you need. The effective compression of a 272 degree cam with, say, 205 to 208 degrees of duration at 50 thou open is still going to work fine with 8:1 compression.
Technically, the only important figures for the cam ar not total duration, or duration at 50 thou, but duration at 30 thou valve lift. Most aftermarket cams have an aggressive ramp, and have less duration at 20 thou than the stock cams. So technically, a 264 or 272 cam will have a similar low speed character to the stock 252 or 256 Ford cam.
Turbos respond to the same good gear normally aspirated cars do. The only problem is running into surge at off turbo (before full boost) with a bigger cam bigger than 280 degrees at lash. At low speed, there isn't the stable air flow there is with a 252/256/264 or 272 degree cam.
David Vizard had a great situation where a little low compression 2.0 Pinto engine got a something like small 272 degree Isky 134 cam, and then went to a bigger 280 cam and got a great improvement in power and torque with one of his customers turbo engines, an improvement everywhere. The 134 Isky cam had less duration at 50 thou than the stock 268 degree Ford OHC cam!
Other OHC Pinto engine builders he worked with found that over 300 degrees, its very easy to over cam the engine and get into a surge zone. Peak power still gains, but then there is a low down, low speed drivablity problem. It cannot be fixed by sizing the turbo up or down, and results in all kinds of issues.
The summary will be the same with a 200 I6 as with a 2.0 Pinto engine. You can't over cam it if its below 272 degrees.
If your car has a poor breathing head, its okay to go for a wilder cam. The Aussie X-flow headed 250 ran factory cams of up to 264 degrees with a free flowing head, and the car was very tractable with 8.7 to 8.8:1 compression.
It's hard to imagine a 272 degree cam ever having problems in a 200.
Turbos can make boost at any RPM range. It all depends on which turbo you select. Size is critical and the right turbo for the street may not be the right turbo for the strip.
You need the smallest turbo that will make the boost you require at your max intended RPM without overspeeding the turbo. A larger unit will make more boost but it will only do it at the high end of your RPM range; this is the critical mistake that most riceboys make. They end up with dyno warriors that make 5 HP per CID but cannot get out of their own way on the street.
If you go too small though, you will be into the wastegate at every shift and lose beaucoup HP in the process. You need to learn how to read a compressor map and select accordingly.
You need the smallest turbo that will make the boost you require at your max intended RPM without overspeeding the turbo. A larger unit will make more boost but it will only do it at the high end of your RPM range; this is the critical mistake that most riceboys make. They end up with dyno warriors that make 5 HP per CID but cannot get out of their own way on the street.
If you go too small though, you will be into the wastegate at every shift and lose beaucoup HP in the process. You need to learn how to read a compressor map and select accordingly.
StrangeRanger":2cu70knb said:
the turbo I have is a T3 super 60. which I have read the map and used the ray hall calc and found it will run 72% efficent with the 200, at 5k RPM running 15 psi of boost ( Lincs 200's faq suggest doing the 15 PSI for the calculation because it is close to 14.7 which is 2.0 preassure ratio, so easy to read ).
