Cam retarding?

[Swifty1638]

I was looking into more and more (after talking with andrew) aout retarding my exhaust cam a few degrees, to try and help spool up. After talking to Lampi on the topic, i find even more that people do it often as a way to spool because it allows the exhaust valves to open during the burn, and therefor, the hottest gasses escape to the turbo helping spool. But, it also causes motor damage to valves and such. I was going to just turn the exhaust cam gear a few notches, but does anyone really see a big difference in degreeing theirs? Anyone else do this? How much did it really help spool or not?

-A. Swift

[Swifty1638]

So the ways to increase spool speed so far mentioned:

-Ball and spring MBC
-Retard exhaust cam or advance intake cam by one tooth
-Open/better flowing exhaust (cutout)
-Retard the timing and richen the fuel : I've had decent results actually leaning out because it makes then exhaust gases hotter. I don't want to make a primative antilag effect, I jsut want to make a little faster spool, since Work done by the turbine = Massflow X Cp X (Temp exhaust manifold - Temp down pipe)
-True cold air intake
-Tubular exhaust manifold
-higher spring preload on the wastegate

-A. Swift

[asshanson]

One tooth? Isn't that like 6*? I was thinking more like 3* or so, 6 is quite a bit, and probably the ghetto way to do it for those who don't have adjustable gears.

[Swifty1638]

yea, i copied and pasted that from talk. I gotta double check my gears too, as one I think has 0* at the valley of a tooth, and the other is at the top of a tooth..I forget which is which though..eek.

I have a cutout on the way, and am trying to figure out how else I'll spool quicker.

-A. Swift

[Swifty1638]

I'm thinking 1* advanced on the intake cam, and 3* retarded on the exhaust cam..could this be the sweet spot?

-A. Swift

[Matt D.]

Wouldn't you want to advance the exhaust cam so when it opens the air-fuel mixture is still burning? If you retard the exhaust cam it will open later when the burn is further progressed and more of the energy is already spent, leaving less for the turbo. Retarding the timing is the same thing, the burn starts later allowing more energy to be fed into the exhaust and less contained in the combustion chamber.

Ask me how I know... I had a Ford 302 once and the vacuum advance fell apart on the distributor when I was on the highway. By the time I was able to pull off without getting ran over I was greeted with glowing exhaust manifolds under the hood. :)

[Swifty1638]

I just know that every site I've seen for dsms, this is how they do it..perhaps that's due to the fact you only had 1 cam? (I know nothing of ford motors)

-A. Swift

[Shane@DBPerformance]

Most of the things you do with adjustable cam gears to help spoolup can hurt topend power a lot. That's the beauty of systems like MIVEC where you can change the cam advance/retard vs rpm/load.

Most of the the things you listed above could very slightly improve spool up, but maybe not enough to notice, unless your exhaust is really restrictive of something. A tubular manifold usually adds a decent amount of lag. An OEM or FP style cast exhaust manifold will normally drastically outspool a tubular, longer runners, bigger runner manifold. Your best options are to get smaller turbo, get a bigger motor, use nitrous, or just rev higher.

[FattyBoomBatty]

Yeah, get a stroker kit, that'll help spool.

[Swifty1638]

I'm really considering throwing a bigger motor in this car. Revving higher only means it'll be harder to shift..arg.

Shane, should I try anything with the cam gears at all, or just leave them at 0? I have a 3" cutout on the way, and a dual spring WG too.

-A. Swift