Performance Cam

[btfarm]

This thread could not have gotten any uglier that it did back then. I sure hope it's not gonna explode again.

 

[ak diesel driver]

Well in all reality it could have been the cam grinder who is giving all the newfound IDI power. As in same people using the same cam grinder.

 

[Husker6.5]

This is only part of the reason why the ATT works, If just putting a larger turbine housing on made an engine more power, then any turbo would give increased performance, ::: (IF you have enough drive energy,) The turbine wheel is configured for the right drive pressure and energy for a given rpm range, then we get into whether the turbine wheel has enough drive energy to turn the compressor wheel efficiently through an rpm range. Make the compressor wheel design wrong and you won't be able to spin it when you need to, make the compressor wheel to small and you over drive it, just as bad.

Change the bite of air and now you affect speed and drive energy again, Turbo charger design is an art and partially science. The guys that design them have fluid dynamic brains that make better calculations than computers do, the computers just help confirm what they think, might work. Wonder how they did this before all of the cad cam design and super computers?

Slide rules, my friend, slide rules. Just like the one I used up through my sophomore year in High School before plunking down almost a month's worth of part-time after-school employment to buy a TI-30 calculator. The same way we put men on the moon, built the first A-bomb and designed planes, trains, cars and other things that outlast the junk that's computer designed to the Nth degree and fails when the old-school stuff would take a beating and keep coming back for more.:thumbsup:

 

[Slim Shady]

Slide rules, my friend, slide rules. Just like the one I used up through my sophomore year in High School before plunking down almost a month's worth of part-time after-school employment to buy a TI-30 calculator. The same way we put men on the moon, built the first A-bomb and designed planes, trains, cars and other things that outlast the junk that's computer designed to the Nth degree and fails when the old-school stuff would take a beating and keep coming back for more.:thumbsup:

I LIKE THE WAY YOU THINK :agreed:

 

[Husker6.5]

I LIKE THE WAY YOU THINK :agreed:

I just like the fact that I can think! Unfortunately there are way too many people out there today who seem incapable of thinking!:mad2:

 

[turbovanman]

Bump, any new info? lol.

 

[Paveltolz]

I'm enjoying mine. I haven't run the truck on the dyno mainly due to time available and partly because I've been wresting getting an optimum tune to the new turbo sorted out.

That said, regardless of GM-5 or Garret / Eco-neuter Tune or performance Tunes / HO or Standard Bosch injectors, the truck was noticeably livelier across the board even before we got things sorted out. Power band is wider, responsiveness at cruising speed much improved.

Now that the Turbo and Tune are worked out, its fantastic. Unfortunately, how much is credited to the Cam (HT-4) or, how much the new motor is to credit is an unknown.

In hind site, had I saved a bunch of money and just re-ringed the old motor with new bearings, crank and cam kit I could give an honest assessment as to the differences.

 

[turbovanman]

Gotcha, thanks.

 

[Slim Shady]

There are gains to be had in the cam grind, but how much is lost in the new motor rebuild and the addition of anything other than a bonified cam only change. I suspect that when you increase the cam overlap and you lose piston to valve clearance, based on valve event timing changing and giving lift stays the same. As a few people that I have spoken with early on , they did not adhere to given engine rebuild practices and bent a few push rods, Luckly a recomended .010 plus head gasket gave them enough clearance.

With eigteen to one I could go with even more overlap but not sure how much I would gain or lose in different areas of the power curve. I do know BIG pre cups give great lower end and great top end but lose a little in the efficiency area at moderate rpm (1200~1400) and big load, someplace the regualer pre cups excell. Everything is a give and take. And I am not sure the Delta cam didn't come close to the best cam for a stock valve train. But I am not a skilled cam designer so everything i say is just a wild a-- guess. Just thinking out loud. That may be my next area of experimentation, I do know that pre cup design makes a big difference in fuel injection timing, flame front and the whole combustion process, I love being able to idle the motor in third gear in stop and go traffic makes it much less stress full .

First turbos were no good to modify then cams and both have been proved wrong. Build it then check it yourself don't beleive anyone. Precups were also not changeable, with the advent of my own tunning that proved to be wrong as well, Since I now have a very workable tune and truck. The pre cups in our engine are very very forgiving of poor tuning, not so with very large pre cup opennings.

 

[Bostonguy]

I'm running an ATT and 4inch exhaust, larger crossover pipe, kojo tune. I'm either going to rebuild the engine or buy a teds engine. I haven't made up my mind. However, a performance cam can be part of the rebuild kit. Need more info before I decide, but leaning toward teds.

 

[floyd400]

Bump for new info. Chevyinlinesix: did anything become of the headers or custom cam grind you mentioned you were working on? I'd love to get a good flowing set of headers for my truck.

 

[FellowTraveler]

Just my 2 cents, adding more overlap will help any blown of turbo vehicle however lots of overlap and the cost is insane post turbine incinerator temps and short lived turbo and perhaps the motor.

I found this out when I ran a turbo modified gasser and started to play with crazy n/a cam grinds and lots of overlap the hp/tq gains were insane but the damage from the heat generated in turbine exhaust from the unburnt fuel stopped me dead in my tracks.