I just had a nearly stock TBI engine dyno'd today. 177 HP @ 4,200 and 261 ft/lbs @ 3,600, the lowest speed tested. This engine has pulled over 320 RWTQ down around 2,300 rpm on a different dyno and in cooler weather. Keep in mind that the IAT readings were around 120-130* and the shop was 106* inside. The coolant was even above 200*. This is on E10 gasoline and in fully street legal form.

Stock 350 HD Shortblock (8.5:1 compression)
810 Swirl ports with light port cleanup
Stock Peanut 305 Roller cam with 1.6:1 roller rockers
1.5" x 3" flowtech cheapy headers
2.5-3" Y-pipe, Single 3" cat, 3" single in, Dual 2 1/2" out turbo muffler, dual 2 1/2" pipes
Edelbrock 3704 Intake
1" open center TBI spacer
Stock sized TBI unit with ultimate TBI mods
RBob's EBL with custom tuning
61 lb/hr injectors @ 17 PSI

This engine does everything that I need it to, including getting 15-17 MPG CITY!

 

This basically backs the GM rating of 170/255 for the smaller 305 LO3. I assume this was an engine dyno? Cool stuff.

 

Nope, it was measured at the wheels through a 700r4 with a 2,800 stall Yank converter, 2 piece driveshaft, and 8.5" 10 bolt rear (3.73s)

Anybody that is looking for a chassis dyno in the DFW area should check them out. $65.00 for 3 pulls with an A/F mixture probe in the pipe.

Speedtek Performance specializing in high performance parts and service.

Also keep in mind that the stock Caprice 350 with the same cam is rated at 180 FWHP and 300 FWTQ.

 

Why such a high stall TC?

 

Fast....... what kind of mileage do do you think is possible with 3:73's with a T5 with a .63 OD gear? This is a 305 with Vortecs, LT4 cam, Headers and full exhaust running the EBL. Going up from 3:08's.

DM

 

Becuase it was already sandwiched between the engine and transmission. Plus it makes it jump out of a stoplight like it has more power than it really does.

DM- I think you should be able to average 20 MPG with non-aggressive driving.

 

Kool.......thanks. The mpg is one reason that I have been delaying the change.

 

Just to double check, we are not talking the HOT cam are we? I saw LT4 cam and have production LT4 cam in mind. With the HOT cam you will see around 15-17 depending on the tuning.

 

No.........just std for now. I planned on the HOT cam when I changed back to the 350 but I already have a ZZ4 and just may use it to save some cash. Will the ZZ4 be a little better on gas than the HOT cam?

 

I would have to calculate the overlap, static compression ratio, and dynamic compression ratio to tell you for sure. They would be pretty similar. The LT4 hotcam should make more vacuum since it is obviously EFI biased from the start.

 

The Hot cam would make more vacuum than the ZZ4? Hmmm

Right now I'm heading out to the shop to change the 3.08 to the 3.73. I guess real world mpg is in the future.

Thanks Chris


DM

 

Fast,

What AFR curve are you using for your WOT runs? I'm finding that my motor seems to like somewhere around 12.7:1. I'm using the EBL Dump File and looking at the acceleration curve for each second of WOT.

 

It starts at 12.5:1 and decays down to 11.5:1 after several seconds @ WOT. Stoich on E10 is theoretically 14.1:1 and therefore when I was running 12.9:1, it was too lean. I am making more power at 12.5:1 than I was at 12.9:1, and 11.5:1 may sound very rich, but in reality on this fuel it is not.

 

E10 is ethanol?