Tuning for power question

At the last autocross, a friend did a run in Tom Celica. He said it felt good, but down on power. I hadn't messed with the engine in a while, but thought I'd poke around and see what I could find. It did seem like it should be faster than it was.

I had a feeling it was timing advance. Thing just fell on it's face at 5,000 RPM. So I got out the timing light and had a look. Oh, need to pull the vacuum advance. Uh, nothing happened. I had the vacuum advance hooked up wrong.

That got me to thinking. After I got the advance working right, I gave it some more initial timing advance and that seemed to help. Autocross isn't about power, really, especially in an FSP car, but what simple things should I be looking at to eeek out everything it has to give?

Car is an '84 Toyota Celica with a 22RE. Factory EFI, balanced, open element filter on a bigger air meter. It has a header and full exhaust. No cat right now. It does have an adjustable cam gear set at zero right now. Thinking about retarding that just a little to move the power band up, but don't want to kill my low end torque.

What are the common tips to dial in the last few HP?

Thanks,

Ed

I don't like adjustable timing sprockets. I've seen sprockets where the zero setting was off, and the markings incorrect. I will only use one if I have a degree wheel to set it up with. Retarding your cam timing will almost never result in more power. Advancing will sometimes. It depends on where factory zero is. Are you sure your A/F is right with that bigger air meter? With that head design, I think it will want lots of timing. Keep advancing until it either pings or stops making more power.

I set the cam up with a degree wheel. It's retarded just a tic from having the head milled- a little less than one degree.

I have an Innovate wideband and adjusted the wheel on the air meter to get the A/F back where it should be. Though I was chasing another problem when I put the bigger air meter on. Might be worth swapping the stock one back on now that it's running right and see if it feels better. I have a larger throttle body, but will have to mess around a bit to get it on the car. The truck guys swap the bigger air meter and throttle body and they say it increases power. But, people say all kinds of stuff. With the stock TB, the air meter may not be helping at all.

It did seem like I could keep giving it timing. I was also thinking I should get some high octane gas in it. can probably advance it even more then. I used to do that on my old Ford 2.0. I'd advance it 'till I heard a little ping, then back it off a tic. I didn't even have a timing light back then. It made enough difference to feel. I'll keep chasing the timing for a bit and see what I get.

Maybe I'll leave the cam timing well enough alone until I get it on a dyno.

Thanks,

Ed

Sounds like you've done your homework. Stock cam? Do you know what your intake centerline is?

Zomby Woof wrote: Sounds like you've done your homework. Stock cam? Do you know what your intake centerline is?

I had notes on everything when I did it, but uh, not like me to keep anyting... or remember. Can't tell you how many times I get into something and scratch my head "I know I did that for some reason... what was it?"

It's a stock cam, though.

xSP cars can make really good power. Most prepped 4 bangers in xSP seem to be in the range of 40-50% more WHP than the stock motor. A lot of the power advantage over ST comes from intake manifold tuning, basic headwork, and the ability to run a full standalone computer.

So... how serious are you? It sounds like you are still in ST prep levels except for milling the head.

I'm real serious, but haven't done all the development I plan to do. The '82 to '85 Celica is "on the same line" and they changed the engine and EFI a bit in '85. I built the '85 engine and swapped it in under update/backdate. I have everything to update the EFI which was good for a couple of HP, but also lets me go to a PNP Megasquirt. Those will all get done in due time- probably the EFI swap at least this winter. For now, just want to make sure I'm not leaving any "easy" HP on the table before Nationals. The car is starting to do okay locally, and FSP competition locally is pretty much "the bar" nationally. I'm off the pace, but hope to at least be mid-pack for my first nationals. We'll see.

I'm not sure I'll be able to wring the kind of power increase out of the 22RE that more modern engines can see. But, I have more going in, so may work out. The 22R from all I read just doesn't breath well and all the things that would help it a lot aren't legal in SP. From what I read, it really wants a different cam and some porting work. Out of luck there.

fast_eddie_72 wrote: I set the cam up with a degree wheel. It's retarded just a tic from having the head milled- a little less than one degree. I have an Innovate wideband and adjusted the wheel on the air meter to get the A/F back where it should be. Thanks, Ed

What was the a/f before and after the cam movement back?

The reason I ask is that I'm not all that confident that early EFI systems like that can find little air details like that.

Ignoring the ECU, and just going for pumping first- see how it tunes to get the peak air flow. After that, then if there are a/f adjustments you can make- get the fuel to be as close to LBT as possible (call it 12- 12.5:1 on gas). THEN play with the spark timing.

It's also important that you look at the reaction across the rev range, and KNOW what range you want to drive at. As you did point out, you might be willing to drop some mid range for top end- so as long as you know the range you want to optimize, you are in good shape.

Eric

fast_eddie_72 wrote: I'm not sure I'll be able to wring the kind of power increase out of the 22RE that more modern engines can see. But, I have more going in, so may work out. The 22R from all I read just doesn't breath well and all the things that would help it a lot aren't legal in SP. From what I read, it really wants a different cam and some porting work. Out of luck there.

Porting work is legal in SP. Up to 1" into the head.

As far as the power on the table right now... I'm not much help. Good luck though.

I can adjust the A/F at the air meter. You have to lean it out a bit to get the Supra meter to run right on the Celica. I may have it too rich right now. It in the low 13s at idle. I'll have to get some highway entrance ramp runs to see how rich it goes, but it goes pretty rich when you're on it.

I didn't have a wideband on it before I built the engine, so I don't know what it was. Really might be a good idea to swap a stock air meter in again and see what it does, just to get a baseline. I was chasing a lean idle problem at the time and thought the air meter migh be bad. Only other one I had was the bigger one. The bigger one fixed the idle when I put it in, but only because it made things very rich. That's when I bought the wideband to see what was going on. It turned out to be a bad idle control valve causing the problem. Once that was fixed I leaned the meter out, but left the big one in since I was going that way anyway.

I really need to learn more about A/F ratio and where it should be. I messed with it until I got something in the neigbornood of 14.7 while crusing on the highway, but that may not be optimal.

Back in the day my friends had some Toyota tuning book they used to modify the 22R's in their pickups. They were mid 90's trucks, so I don't know if the mods will work for you. They re-clocked the spring in the air mass meter and added a variable resistor in series on the coolant temp sender. Supposedly that little mod was worth one car length in a 1/4 mile.

Match port the head and manifolds? Shave the head and block to maximum specs to get a little more compression?

In reply to fast_eddie_72:

14.7 while driving is fine, w/o a cat, you can run that leaner for better fuel economy if you want to try.

Peak power- 12-12.5:1, if you are worried about temperatures, lean toward 12:1. But at that a/f, you can be more aggressive with spark, too.

Not sure what your ports look like but... is filling in a port considered porting? You might find so called velocity porting where you fill the port with epoxy putty to raise the floor increase the short side length and speed up the air flow to help more the magic number seems to be choke the port to 60% the valve head diameter. Some ford guys figured this out years ago and came up with a rig dubbed the "tongue depressors? as they looked like the wooden sticks the Doc stuff in your mouth.

Pat Bradens book on tuning Toyotas should help, and offer some ideas