You are correct. All F-body owners complain about the lack of space
under the hood. It's one of the reasons I think why people buy
more Mustangs, because of the lack of user-friendliness the f-bodies
have to offer. I wish those two cars were outside my house, I'm
actually at work and they're sitting on our used car lot. But the
f-bodies are one thing. Mustang owners, could probably pull it off.
Come to think of it, I might just have answered my own question.
I think there are quite a few (2-4 is probably a bunch in the domestic
land) Mustang turbo kits available. I was just always more partial to
GM over Ford, so ?I nver read any of their magazines. It is just the fact that the F-body is such a tight fit under the hood.

Then how are aggressive cams for turbo cars designed? 264 or 272
seem to be the numbers that pop up as far as degrees are concerned
for my Eclipse anyway. Are they also letting air leak out? Surely not
right?

 

I don't think so. The HKS and Webcams are (although big for DSM's) relatively small profile-wise compared to the V-8 cams. They would have to be, or guys wouldnt be getting such great numbers out of them. This is the whole reason I love this board. I am gettign exposed to more than just DSM info.

 

Dave,

Those cam numbers are pretty much the norm.... Check out these values from Crower for B-series engines with VTEC (values - 1st line advertised duration, 2nd duration at .050, gross lift w/1.55):

Stock replacement/Turbo
Int-279 mid Exh-280 mid
Int-234 mid Exh-220 mid
Int-.422 mid Exh-.378 mid

Stage 1 - Street Use, CTR+ profile. (12-15 hp)
Int-282 mid Exh-277 mid
Int-239 mid Exh-229 mid
Int-.446 mid Exh-.413 mid

Stage 2 - Turbo special design. Short duration = low overlap, high lift for increased performance.
Int-280 mid Exh-276 mid
Int-230 mid Exh-226 mid
Int-.465 mid Exh-.445 mid

Stage 2 - Road/Rally & Street/Strip (18-21 hp).
Int-297 mid Exh-287 mid
Int-248 mid Exh-240 mid
Int-.466 mid Exh-.465 mid

Stage 2 - Stock idle lobes w/63402 VTEC lobe.
Int-297 mid Exh-287 mid
Int-246 mid Exh-239 mid
Int-.466 mid Exh-.465 mid

Stage 3 - Drag race profile (23+ hp w/other mods)
Int-295 mid Exh-293 mid
Int-257 mid Exh-246 mid
Int-.472 mid Exh-.466 mid

Notice for non-Turbo the rotaion and therefore the overlap between the exhaust and intake are substantially more than for the Turbo cams. But the lift is comparable. So when designing turbo cams you try to optimize valve opening by both lift and duration without increasing overlap... unfortunately, your only minimizing your losses... you're always going to lose some boost.

Ultimately, the only perfect answer are camless solenoid actuated valves like in BMW motors... allowing for ECU controlled valve opening. But, for most that's just to complex too tinker with, and way too costly... so cams are here to stay. Hell rod actuated valves are still going strong.

Gary

 

Come to think of it, I do remember reading about the latest BMW M3
engine in which the writer was gushing over how great it was -
that the mere on/off high/low effect of Honda's VTEC was mere
child's play, and that iVTEC and Toyota's VVT-i was a better
adaptation but still way behind BMW's system. But then also,
it is amazing what GM/Chevy can do with a set of pushrods with
their LS6. I'm sure Mercedes would have come up with something
just as good, or better, but they were probably too busy trying to
figure out how to but an airbag in the windshield visors.

Right.