chevy1963

Ok here's my problem, I hope ALL the experts can help, or get me in the right direction.

Check the mods below. Well I had the car dynoed a few weeks ago and it got 207 HP with the below mods. The guys dynoing the car said the air/fuel ratio was 17.1 So noticed that I have the LT's with emmison hook ups and I had the wrong O2's in. I didn't have the HOT o2's in so i made the switch and installed a air/fuel ratio gauge and it seems to be working fine, but do i have to buy O2s sims for the second set of 02's that i left disconnected under the car. would this cause a MAJOR pwoer loss?

well i them went to the track this weekend and with the samw set up I could only run at best 14.6 when before I ran a 13.9

I think this car should be running faster then 13.9 with these mods.

Can any hel p with this... IT's starting to off. and before I spend more money I 'd like to get your input

THanks

TedH

My guess is with traction you should be mid 13's at a decent sea level track. However 207hp isn't going to get you there. Something is seriously wrong. I'm actually suprised tou ran in the 14's with only 207 hp. Perhaps the tranny/torque converter is slipping and you did not get an accurate dyno graph? Can you post the chart?

chevy1963

The car is all so back firing sometimes when I get off the gas. I ran a 14.6 this past friday after the dyno and I'm having 2.1 60 foot times.

I'm replacing the plugs today. AC delcos

I also don't have the air pump hooked up to the headers it just blows air out of the tubes will this cause power loss?

chevy1963

TTT, does any one else have any in put? shoebox maybe?

97FormulaWS-6

it's not going to help anything... and it's going to MAJORLY screw up your O2 readings... you get them plugged and then see what happens...

basically you have a HUGE header leak if you have the AIR fittings open...

Injuneer

You really need to ask for help BEFORE you do the mods.... wrong O2 sensors, no O2 sims in the aftercat position, open leaks from the missing AIR tubes..... I'm surpised it ran 14.6

Do you have an SES light? Have you had it scanned?

chevy1963

sorry, I forgot I did block off the hole on the headers where the AIR pump tubing hooks into, The AIR pump is just throwing hot air out the brass tubing because i don't have them blocked.


I do have the right O2's in now. I don't have the secondary O2's hooked up.

My car had dual cats so 4 o2 senors 2 before the cat and 2 after. I don't have the 2 after hooked up.

The car isn't thowing any codes either.

Injuneer

Maybe a few of us misunderstood your original comment... I thought you meant the header AIR connections were open... and I think 97FormulaWS-6 had the same conclusion. Just dumping the AIR pump output (if that is what you are saying - still sort of confusing) wouldn't hurt anything, as long as there are no holes in the headers.

chevy1963

yep, I may have worded it wrong. no holes in the exhaust no leaks.

any suggestions on why the times are bad.

Injuneer

What was the MPH on your 14.6-second pass? MPH is a much better indicator of HP than the ET. What was the temperature and barometric pressure (or equivalent density altitude) when you ran?

chevy1963

the MPH was around 94 I'm not sure what the bar pressue was but the humidity was about 50% and the temp was 80.

I ran a 13.9 at 100 with the same set up but that was with the wrong O2's in.

Injuneer

94MPH would indicate even less HP than you dyno'd.... about 235flywheel/192rwHP. The high temp and humidity might explain the further loss below 207rwHP.

Definitely major problems on the engine, and not surprising at 17:1 A/F ratio (assuming they put the sensor in the right place????). You need to find out why its not getting enough fuel, before you grenade the entire engine.

chevy1963

I did hook up an Air/Fuel ratio gauge since the dyno and it's reading Stoich, not even close to lean more on the rich side.