Cam/header talk..

[myclone]

Me and a mustang bud were bsing this AM over coffee and waffle house gut bomb scrambled eggs and he subject of roller "turbo cams" came up.

Basically we were trying to decide what grind roller cam would be best for a turbo app. We both kinda thought the following:

Lotsa lift (as much as will fit in the block and the valve train will support)
Wide lobe seperation (~111-114 deg)
Fairly mild duration (~265-low 270s deg)
Little overlap
Maybe close the exhaust valve a little late to let the pressurized intake charge help get the exh out of the cyl (dunno if that would help much)

Another thing that came up is the relatively small headers that are available for the syty. The ATRs have 1.5" primaryies but with a loose converter(3-3.5k), good flowing intake/heads, a decent cam, and of course some custom tuning Im thinking we might benefit from 1 5/8" primaries. Yes? No? Dont eat at the Waffle House anymore?

Im not going to run out and purchase a custom ground cam (yet) but the discussion we had was interesting but it was only two ppls thoughts/ideas. Whats the rest of the planet think? Do they care?

 

[TURBO TY]

from what i was always told " bigger is not always better". especially dealing with the cam. i have seen 5.0 mustangs run deep in the 11s with a stock cam , motor work with a turbo. if you have a decent sized turbo with the right combo: heads, intake, injectors, chip , convertor, gears , turbo the need for a really bigg cam is a waste. now if you you are running all motor then a bigger cam will be more beneficial.

 

[Sy769]

Re: Cam/header talk..

Me and a mustang bud were bsing this AM over coffee and waffle house gut bomb scrambled eggs and he subject of roller "turbo cams" came up.

Basically we were trying to decide what grind roller cam would be best for a turbo app. We both kinda thought the following:

Lotsa lift (as much as will fit in the block and the valve train will support)
Wide lobe seperation (~111-114 deg)
Fairly mild duration (~265-low 270s deg)
Little overlap
Maybe close the exhaust valve a little late to let the pressurized intake charge help get the exh out of the cyl (dunno if that would help much)


Another thing that came up is the relatively small headers that are available for the syty. The ATRs have 1.5" primaryies but with a loose converter(3-3.5k), good flowing intake/heads, a decent cam, and of course some custom tuning Im thinking we might benefit from 1 5/8" primaries. Yes? No? Dont eat at the Waffle House anymore?

Im not going to run out and purchase a custom ground cam (yet) but the discussion we had was interesting but it was only two ppls thoughts/ideas. Whats the rest of the planet think? Do they care?

First of all Waffle House rocks!
Just like a NA cam needs to be matched to the application turbo cams are no different. The turbo you are running can vary the optimum cam. Depends a lot on how much pressure you have in the intake or exhaust.
Close the exhaust valve late with a high pressure turbine and you risk reversion, or with a freeflowing turbine you get send some of the intake charge right out the exhaust valve which hurts in several obvious ways.
*Wide lobe separation is good
*Lotsa lift is good
*Short duration is good as we don't need the long duration for cylinder filling more concerned with mainting good cylinder pressure.
*No overlap on a high pressure turbine but a little could be tolerated on a properly sized turbine.
There are other variables for sure but I know the 412 cam has to be a compromise.
I've got a good idea on the cam for my build using a stock turbo. Why a stock turbo? No cashola for the PTE kit. But I do need a cam and I think the Vortecs,JE's,Eagles,4boltmains, would all raise 7 kind of hell if I put a stock cam back in the block. They're pissed enough about the turbo situation.

 

[myclone]

Turbo Ty,

IMO you are correct about "bigger isnt better..." to a point. Looking over the stock cam specs will reveal how pathetic the specs are with perf in mind. For a smooth idle (hahaha thats funny in a way to us syty ppl), gas milage, reliability, etc the stocker is more than adequate but for perf oriented application its not even in the ball park IMO. With my limited research into what makes a "turbo cam" diff it looks like you really dont need all the "bad" charactoristics that a high perf cam usually imparts on the driveability like lopey idle, super high stall, etc. If my research into the matter is even close it looks like short duration, wide lobe seperation(compared to a "normal" perf cam), and low over lap is what would be desired. Basically those things are what makes a NA perf cam "lopey" and unpleasurable to most ppl (thats a shame as I LIKE "lumpy" sounding cams LOL). What seems to me to be a good choice is higher lift to allow to turbo to pack more fuel/air into the cyl but use as little duration/overlap as poss to keep that fuel/air in the cyl to build as much cyl pressure as a given octane/timing combo will tolerate. Then again my thinking could be flawed as Im no cam expert and only know what Ive tried myself, seen what other ppl have tried, been told, or read.


Sy769,

Sounds like we agree on whats going on for the most part. I also whole heartedly agree with you that the cam specs need to compliment the rest of the build. I was really speaking in generalizations as in "what constitutes a turbo cam if all the other components were matched and the cam was optimized to work with those components?". One turbo build may very well need x cam while a diff set up may work better with y cam.

Closing the exhaust valve slightly late would prolly be better than opening it early (less overlap) but it would take much dyno time to nail down exactly how late to close it. Not cheap to do so IMO, the best thing to do is use an existing grind or rob a bank so trying diff grinds wouldnt be a prob (the going to jail part would be a prob though LOL).

Just more rambling to clutter up the board from me and more thoughts to roll around in the ol noggin when I prolly should be concentrating on other things.. LOL

 

[Fred Aldrich]

One issue that hasn't been touched on is the dilemma that high lift AND short duration presents. Less duration means less time to get the valve open and closed. With high lift and short diration, you have to bang the valve train hard and that's tough on valve train components and limits RPM capibility. Even though the specs on a SY/TY cam are lame, there's a reason why they're that way.

 

[myclone]

One issue that hasn't been touched on is the dilemma that high lift AND short duration presents. Less duration means less time to get the valve open and closed. With high lift and short diration, you have to bang the valve train hard and that's tough on valve train components and limits RPM capibility. Even though the specs on a SY/TY cam are lame, there's a reason why they're that way.

I agree COMPLETELY with ya on that one and its something Ive been pondering. A roller cam makes that easier to do as far as profile but you can only go so far. You also need pretty stiff valve springs to keep up which means money needs to be spent on the rest of the valve train to tolerate high spring pressure. It can get expensive quickly.

The final issue that bothers me is whats the max spring pressure the factory roller lifter will tolerate? Ive researched that myself and pestered everyone I could but have never gotten even the slightest tid bit of info on that. The ONLY time Ive ever seen it mentioned was in a car mag eons ago when factory rollers first came out and all they said was "the factory roller lifters wont tolerate a lot of spring pressure". Thats it. No max numbers.... Well thats fine and dandy but what do they consider "a lot"? 300lbs open? 500lbs open? 700lbs open (thats getting up there IMO)?

Makes me wish at times I had to $$ to call up the likes of Lingenfelter and/or Callaway ask em if theyd like to make ten grand for an hr of phone time so I could ask em what theyve found in dyno testing on this or that part..

 

[10secTy]

General rule of thumb for a turbo cam is to size it 15-20 degrees shorted than normal for the engines desired operating range. A turbo motor make the camshaft seem bigger. A example is the 412 its operating range is 1500-4500 rpm. But when dyno tested peak hp came in at 5000 rpm.
So with a 5500 rpm shift point you would not really want to go much bigger.
You could raise the shift point more but with a stock crank I would rather crank the boost and short shift the motor.

Also the amount of overlap you have depends on what the ratio of intake to exhaust back pressure is. The 412 has low overlap so it is a good choice.
As you add bigger exhaust housings and headers the backpressure will go down. Then you can run the cam specs more like a NA motor.

I am working on a custom cam for my truck, the exact specs wil be finalized once I have the flow numbers for my heads.

Nolan

 

[warmpancakes]

what is the part number of the 412 cam?

 

[10secTy]

09-412-8



Nolan

 

[myclone]

Nolan,

Thanks much for your input also..

 

[warmpancakes]

thanks and thats the part number to give to sumitt? Ken

 

[10secTy]

umm nope not the summit part number. Call and give them that part number they will cross it over to theres.

No problem Dave. Post if you have some more questions. I am sure I did not answer them all

Nolan

 

[nightdiver]

As the time passes by and the mods are being more agressive we all agree that a cam like 412 or 422 and a pair of heads flowing 240 to 300 cfm is the key to success.I choose the 422 cam cause i want to shift at 5800
I also bought sst tubes to make new headers ,KB style,with 41mm diam inside.Its a little bit bigger than the KBs as i also think that 38-39mm is small

 

[myclone]

As the time passes by and the mods are being more agressive we all agree that a cam like 412 or 422 and a pair of heads flowing 240 to 300 cfm is the key to success.I choose the 422 cam cause i want to shift at 5800
I also bought sst tubes to make new headers ,KB style,with 41mm diam inside.Its a little bit bigger than the KBs as i also think that 38-39mm is small

Cool.. I like to shift high myself and dont have prob with spinning a properly built motor to do it. Call me old school or too much of a NASCAR fan but high RPM doesnt bother me any.

All I need to do now is convert your mm specs to inches to see what youre working on. LOL.

 

[Falco]

thanks and thats the part number to give to sumitt? Ken

Ken,

Summit part number for the cam: CCA-09-412-8 ; for the lifters: CCA-850-12

HTH

 

[nightdiver]

I was around europe for ten days and i found a warehouse with used welding machines ,all kinds with very very low prices.I can get a Tig for 100 usd .
Its lokated in Germany near Essen.Ill go back on february and ill buy a few(he he) to do my job
I drove 9500 km in ten days Italy-austria-germany-holland
Thank God i took the mercedes

 

[myclone]

I was around europe for ten days and i found a warehouse with used welding machines ,all kinds with very very low prices.I can get a Tig for 100 usd .
Its lokated in Germany near Essen.Ill go back on february and ill buy a few(he he) to do my job
I drove 9500 km in ten days Italy-austria-germany-holland
Thank God i took the mercedes

Lemme get this straight... You can get TIG welders for a hundred bucks?? That almost sounds WAY too good to be true. :-? :-?

If, in fact, you can what votage are they? What make and model number(s)? If you can send me pics and the specs I requested so I can check em out we might have to discuss this further.

 

[Sy769]

I was around europe for ten days and i found a warehouse with used welding machines ,all kinds with very very low prices.I can get a Tig for 100 usd .
Its lokated in Germany near Essen.Ill go back on february and ill buy a few(he he) to do my job
I drove 9500 km in ten days Italy-austria-germany-holland
Thank God i took the mercedes

Lemme get this straight... You can get TIG welders for a hundred bucks?? That almost sounds WAY too good to be true. :-? :-?

If, in fact, you can what votage are they? What make and model number(s)? If you can send me pics and the specs I requested so I can check em out we might have to discuss this further.

I'd also like some info if you don't mind. I'd love to have a TIG but most are priced too high for me.

 

[nightdiver]

A friend of mine that lives in germany has already bought one, but its a wire type
Actually those industrial machines incuding the welding ones comes from companies that had financial problems,that explains the prices
Ill get back with the spesifications..........
and guys i wish you a HAPPY NEW YEAR :x-mas:

 

[TheObiJuan]

what might shipping for a 50lbs box be to the states?