New Performance Cams for IDI, Not a Regrind. Interest??

[DeepRoots]

sure sure, I get your point of view.
But these people want a "max performance idi"
In my opinion if I wanted the uber powerful engine, I'd buy a 427 block and go from there (thats my style), or start with a 385 series(the cheap way to more power via cubic inches).
If they REALLY want a super 7.3, it really needs to be redesigned from the ground up. Throwing a camshaft alone at the engine will NOT do what they want it to.

Or.... you could just enjoy the fact that you already have the best working, most reliable and simplest designed diesel factory installed in a pickup truck. (I'm in that camp).



ohh and I disagree with the fuel injection comment. It has been stated that the Stanadyne Ip is only good for such and such a power due to how much fuel it can inject. This is true, but only tested to 3300rpms.
The biggest challenge to fuel injection is "Injection lag" and "ignition lag" At higher speeds more advance is needed, but fuel will only ignite so fast.
Of course my 05 Passat readily spins it's 2.0liter diesel to 5500rpms.

Drew

 

[racer30]

I never said it wouldn't rev that high I only said it would cost money to do it, You would need to modify the ip to spin up that far and then, the piston speed would be 3553 ft/min at 5100 rpm so you would need a lighter stronger piston when you cut them down to lower static compression you would pick up the valve clearance and ballance the assembly then run more lift and port the heads on both sides dual turbos it could work. I just don't need a engine like that. the overlap on the cam is what kills the cam you need negative overlap for forced induction 8* to 15* works best. you would need to fill the block and run a diaper on it because its gona put a windo in the block, but it would be fun to watch.

 

[dansvan]

Diesel fuel burns slower than gasoline. Increasing rpms does not give it enough time to burn.

Icanfixitall is it possible the valve marks on your pistons were just areas of higher velocity around the valves that decreased the carbon build up? So it has an appearance of touching but in actuality wasn't?

 

[icanfixall]

Actually the marks are darker than the rest of the piston top so the long answer could be yes.... I know the mark can't be measured with any thing I have... And I have plenty of Starret mics and claipers... Whatever the mrak is its wierd looking on all the pistons...

 

[DeepRoots]

Diesel fuel burns slower than gasoline. Increasing rpms does not give it enough time to burn.

BS. Ever drive a VW or Mercedes that spins 5-6k rpms? How about the Audi that won Le mans? you aren't telling me that it only spun 3300rpms?

 

[racer30]

For what it worth all the runs I made to 4000 rpm with all the cam profiles mild to wild the program never warned me of possible valve float or interference. It has a data line for "valve toss". I am looking for a valve train dyno program to do some testing. to see if it will be able to show what is going on inside the cumbustion chamber.

 

[Black dawg]

how often does cummins suggest you set lash on the 12 valves.

every solid lifter cammed motor Ive ever had runs better even down low compared to a similar hydraulic cam.

 

[OLDBULL8]

I wonder if a 7.3 DI PSD cam would fit in a IDI. Anyone got one to compare to the IDI cam.

 

[DeepRoots]

http://www.swampsdiesel.com/content/projects/Camshaft_Design/

 

[dansvan]

BS. Ever drive a VW or Mercedes that spins 5-6k rpms? How about the Audi that won Le mans? you aren't telling me that it only spun 3300rpms?

yes and those engines are designed with the pistons dwelling longer at TDC to allow more time for the combustion process. Also the abilty to get the required amount of fuel properly atomized into the combustion chamber faster than our idis could ever dream of. No one has addressed that here. It takes a specific amount of time for our engines to inject, ignite, and burn the fuel needed to push our big heavy pistons, rods, etc down. Raising the rpm gives these events less time, resulting in partially burned fuel and no power gain. I'm sure there is more room for some extra rpm from our engines designed in and then backed down for longevity by the designers. But we're not going to just easily obtain 5k. Point being there is more limiting the rpm potential of these engines than a camshaft design.

 

[DragRag]

Wish I had that same info for the idi, still looking for the clearance between valve and piston. If anyone knows that info please post, thanks.

 

[built4tq1]

with higher rail and injector tip pressure along with multiple injection cycles per stroke, better atomization can be achieved thus fuel burning becomes much more efficient.This will allow for higher rpms in a diesel engine. Listen to how quiet these new diesel engines are these days not to mention the rpms that can be achieved in "race" applications without sacrificing efficiency. Lets take a look at a Bosch P7100 pump for example. Now a 12v cummins is not un heard of to spend 5000 rpm in the "race" arena because this pump can deliver up to 18,000 psi pressure stock and do it relentlessly. With this being achievable, now better injectors may be created with excellent atomization due to the fact of its muscle and stamina. start throwing in longer attainable injection strokes on top of better atomization and the engine can spin further in its rpm window. Kinda like jabbing a speed bag as apposed to punching it. Damage will be done either way but the more affective way of course would be a power punch (Kinda the way our db2 delivers) if one was looking just to get the job done. However if those jabs could be as effective as those power punches, continuously more attainable power has been created which allows for continuous power explosions with the same consistency as jabs. Sorry if my analogy sucked just kinda rolled with it. The injection pump is the heart of all diesel engines and I'm not yet convinced our db2's has the endurance needed to keep these engines rotating happily in a medium high performance stand point. Perhaps if we looked into other pump departments such as a VE Bosch rotary pump for 8 cylinders (does anyone know if they make one?) or a practical in line pump, (I know those words don't belong that close together) than we would be working more towards combustion explosion force to make more power and rpms wouldn't be as much of a factor. Although having a good cam built around boost would still be awesome.

 

[racer30]

from reading the specs the 94.5 psd and the idi cam has the same bearing size and lift pump lobe the only thing I see is a provision for cam position sensor has been added. the lift and duration is the same. It has a new part number because of the cam sensor, In 99 they delete the lift pump lobe and give it a new number again.

 

[dansvan]

so do they make performance cams for the powerstroke?

 

[OLDBULL8]

I wonder if a 7.3 DI PSD cam would fit in a IDI. Anyone got one to compare to the IDI cam.

That article is very interesting. It gives me some insight as to what I was wondering about the PSD cam. I'm building up an IDI now. The cam gear should be the same as the PSD and IDI are both 7.3. Would the cam timing be the same? IDI compression is ~22:1 PSD is ~18:1. I know the pistons are totally different for the 99 up DI.