TBI injection

[Mira_cz]

Hi, I have stock 305 engine. I want few more hosepowers. At least for quick overtake on motorway. I think that some performance TBI injection on stock engine could give me about 20 horsepowers more. Maybe with Intake manifold. I don't want to make a streetmachine from my caprice, just few more horsepowers, 20 - 30. Burnout should be great
I heard of GM performance replacement, which you switch for your stock TBI, connect all sensors and cables back, without anything next, ECU modification, etc.
Can you give me some advices, what performance kit should be better?

Thank you very much. Mira

[kdrolt]

Read this:

http://impalassforum.com/noncgi/ulti...;f=33;t=009021

and look for the exhaust upgrade links (9C1 copcar Ypipe + aftermarket muffler) and the DIY cold air intake links. Those two will get you close to the 20+ fwhp gain you want. Stamped 1.6 rockers, new valve springs, and new seals would probably put you over the top.

[Mira_cz]

thank you very much

[wrightz28]

Ultimately, you don't want to be focusing on increasing horsepower, but torque

[Mira_cz]

Yep, I know But any performance parts I found promises increasing of horsepower. Which of parts have the most impact on torque? Thanks

[silicon212]

Originally Posted by Mira_cz

Yep, I know But any performance parts I found promises increasing of horsepower. Which of parts have the most impact on torque? Thanks

There is no such direct thing as "horsepower" when it comes to rating an engine's power output. Actually, there is, but that's not what a dynamometer reads. Engines, like any rotational power device, produce torque and the torque is then converted into horsepower. Basically, everything you do to an engine affects its torque production.

x*y/5250 is the formula that's used to determine horsepower, where x=torque and y=RPM. You can see from this formula that torque and horsepower will be equal when the engine is turning 5,250 RPM.

Torque is the measurement of a rotating device's ability to perform work. Horsepower is the measurement of that torque and RPM combined.

[Blue Bowtie]

Just about the same as any other SBC - heads and cam.

[Mira_cz]

Thank you for advices and explanations. Now I'm going to tell you my biggest problem with caprice. I hope you will understand what it could be from my bad english.

I have 1991 Caprice Classic with 305 cid engine and 274 000 miles on it. It is also LPG (liquid fuel gas, I dont know how you call it in USA) fueled (just supplement of fuel gas/air mixture to the intake), that mean if you want run on fuel gas, you have to push the button and fuel gas system swich injectors off and engine takes what it takes. But there is a problem somewhere.

This Caprice is incredible lazy - it is able to run don on about 20 MPH maximum to normal hill, where other cars can run 60 MPH, even if you push pedal to kickdown and it makes downshift, RPM goes high, but no speeding up at all. I would understand if it would be only on fuel gas, but it is the same on petrol too.
Sometimes, if I want run on petrol, RPM don't want go up from idle and it is "shooting" to intake. But it is only once or twice to the month of daily riding.
Sometimes (it happened to me just twice) everything was normal - even on fuel gas my caprice run like a bullet. I didnt belived it is my car how great it runed. Unfortunately it took about 30 seconds.

I got new sparking plugs, sparking wires, both TBI injectors, fuel pump, and throttle valve sensor.

Please give me any advance. I asked lot of people for advice, nothing helped. Im very sad of it and dont know how to solve it. It would not have anything to do with fuel gas mode, because if you swhich it off, it is just another normal 305 engine. Im wondering if it coul be distributor, or ECM. Maybe some sensor, of fuel pump again?

Thank you

[Blue Bowtie]

it could be a problem with wear ignition. It could also be a restricted exhaust. It could be a valve timing problem. It could be many things.

It the ignition timing set correctly? Has it changed?

[Mira_cz]

It should be ok, but I will check it again.

Yesterday I was running 80 MPH to near town on movie, it was 10 minutes to begining. After about 5 minutes of run, caprice suddenly slowed down, even if I had my feed on throttle still in same position. Check engine soon light up in the same moment. I tried petrol and fuel gas, it did the same thing.
It realy could be a distributor, something with ignition advance or something. I hope it is that, because it make me mad for a long time.

[silicon212]

Originally Posted by Mira_cz

It should be ok, but I will check it again.

Yesterday I was running 80 MPH to near town on movie, it was 10 minutes to begining. After about 5 minutes of run, caprice suddenly slowed down, even if I had my feed on throttle still in same position. Check engine soon light up in the same moment. I tried petrol and fuel gas, it did the same thing.
It realy could be a distributor, something with ignition advance or something. I hope it is that, because it make me mad for a long time.

Is it suffering a power falloff at high speeds all the time? Does it ever have a "hot smell" or "rotten egg smell", or run hot? If so, you might have an exhaust system restriction (usually a plugged catalytic converter).

[Blue Bowtie]

Since the "Check Engine" light has come on, did you retrieve the error code?

[Mira_cz]

silicon: it happened for a first time while running. It happened few times, but only if cars was standing some time. Second thing, I dont have a cat anymore.

Blue Bowtie: I had not reset codes for a month I think, so these four codes can be old - but of course I flash it just when I went home same day.



CODE 43 = Electronic Spark Control (ESC)
Signal to the ECM has remained low for too long or the system has failed a functional check.

CODE 44 = LEAN Exhaust Indication
If voltage to oxygen sensor remains BELOW .2v for more than 20 seconds code is set.

CODE 45 = RICH Exhaust Indication
If voltage to oxygen sensor remains ABOVE .7v for more than 1 minute code is set.

CODE 54 = Low Voltage To Fuel Pump
Sets when the fuel pump voltage is less than 2 volts when reference pulses
are being received.

Thank for advices guys, I hope we can find it out.

[Mira_cz]

silicon: And there was no smell of anything.