306 dyno results

A buddy of mine just got his 306 dynoed and made a whopping 258hp and 280tq. He's got gt40p with 3thing valve job, 1.6s roller rockers, ported, f-cam with holley systemax intake and shorty headers with h-pipe. he's got the stock inj, maf and gears with a 5-sp. He set the timing at 12*. They found a problem with his ect. They told him he was running rich because of this and causing power loss. Does this sound right? What should he be at?
Thanks
 
Zero Signal said:
I think the 20hp came from the assumption that you are replacing an old worn out stock shortblock with a very well built 306.

I didn't gain anything with my 306 and longtubes from my old 162k bottomend.

I also added a ported intake, which I attribute to the gain of the .51 mph I gained after those additions.

The new engine was probably pretty tight, it had about 1000 miles on it.

A loose engine has less friction (lots of miles) and can free up some horsepower.
 
5spd GT said:
I didn't gain anything with my 306 and longtubes from my old 162k bottomend.

I also added a ported intake, which I attribute to the gain of the .51 mph I gained after those additions.

The new engine was probably pretty tight, it had about 1000 miles on it.

A loose engine has less friction (lots of miles) and can free up some horsepower.


actually, a loose engine has more friction from improper oiling and increased vibrations.
 
5spd GT said:
Talk to the Pure Stock guys;), as 25thMustang says..."loose is fast"...

Many know tight engines can eat up a bit of power...

Loose is fast is a term referring to driving style, not sloppy engine build. Loose is when you are cornering at the car's limits, and it slides a bit, with cars like ours, we usually oversteer a bit. Loose is a term referring to oversteer. When a car is loose, you are swinging it around the corners, maintaining your momentum, making higher speeds on the straights, "tight" cars that understeer, will plow the front end through turns, scrubbing off momentum that needs to be built up again during the straights. I wll agree with you on this though, an engine with too tight of clearances will eat power, that would be an improperly built engine, but the same goes for too much slack. An engine with loose connecting rods will rattle and not sustain high rpms or horsepower. An engine with loose tolerances on the main bearings (crankshaft) will have a crank that vibrates excessively, ruining harmonic dampers and wearing the timing chain/lifters and valveguides. Not just that, but the crankshaft would walk back and forth in the block. I could go on. If loose tolerances were beneficial to engine builds, then everybody would be doing it, and burning a lot of oil in the process. I know for sure that Panoz, with thier 7000+ RPM 5.0 that they used to run a few years ago, generating about 500 N/A horsepower did not have loose engine tolerances. that goes for LeMans endurance racing as well as Trans-Am and Grand-Am cup. hell, the same goes for nascar and top fuel. If you still don't believe me, go ahead and call a local performance engine builder.