Dyno tuning for a stock M20

[jblack]

So,

I am signed up for a day long (yes - day long) dyno tuning session for my basically stock M20 engine.

Things I won't be changing:
Chip Programing (must remain stock
Exhaust or header (currently has stock header and down pipe into a "Y" - single pipe to the back to a glass pack)
Injectors (must remain stock)

Things I may change (but I am almost 100% sure there is no gain to be had):
Stock intake (everything I read tells me the limitation is at the AFM, not the stock intake)
Moving to an aftermarket Furl Pressure Regulator (I hear the only gain to be had here is if the ECU can adapt to the increased fuel presented - which I can't change)

So - what can be adjusted within the parameters I list above to get even .5 hp more out of the car?

Things I think I'll get out of this:
Adjustment to timing
Discover if my injectors need to be cleaned/replaced
Cleaning and adjustment (?) of AFM

Obviously - this is a Spec E30 (first with a logbook in Florida). I posted here, as you seem to have the most knowledge on the topic of engine tuning around.

Where should I look (within the above parameters) for anything I'm leaving on the table?

BTW - the engine is bone stock now - only mods are an oil pressure light (not gauge - just a big red light that comes on if the pressure drops below 12 PSI) and a crank scraper. Engine is original to the car (was an auto until I put in a 5 speed) with 85k miles.

Thanks for any input.

If you want to see the car - http://web.mac.com/natblack/Black_Si..._Race_Car.html

[E30_fiend]

So you dyno'd it.

Any specs you want to share with us?


E30_Fiend

[jblack]

I am looking for input for the guy that is tuning it. The session is scheduled for Friday.

So - no - no numbers to share yet.

[Coouuper S]

I am really interested in the numbers. My pretty stock Cooper S went from 178hp to 192hp with a good tuner and pulling a bit of timing. I am dieing to know what you can do with the m20.

[jlevie]

Given the limitations imposed by the SpecE30 rules, the cost of the dyno day will be wasted. The only way to fiddle with timing is via a chip change, and that's not allowed. You could fiddle with the FPR, but a properly operating OE FPR is as good as it gets. If in doubt, have the injectors cleaned and tester, or simply replace them with new OE parts. In a like manner, fiddling with the air box is isn't going to gain anything. As long as the AFM vane is free and the pot is good, that's as good as it gets.

As to the exhaust, acquire and install the SpecE30 exhaust if you don't already have that in place.

Deleting the engine fan (replacing it with an electric) and power steering is probably worth more than what you can get from tuning...

[jblack]

Crank driven fan is already deleted (I rewired the existing fan a la Euro M3s, with the OE brackets)
Power steering is already deleted
Spec E30 Exhaust is already installed

The price is very right on the Dyno time - I am splitting it with another Spec E30 guy (so we can compare numbers back to back on the same dyno) and it is 200 bucks total for the day, including any tuning needed. So it isn't big bucks.

The car is low miles (85K) and spent 79K of those miles as an Automatic, so I think it is relatively fresh. But, as most know, the 1-2 HP on a spec car is worth a lot.

The car is right at the Spec weight. About all I can do is mess with the alignment and make sure my motor isn't down on power as compared to the field. Then, there is only one remaining weak link....
:)

So - Injectors
FPR
AFM (confirm vane is free and the pot is good)

Not much to play with - the other car getting the dyno time still has A/C, Power Steering and a non-Spec exhaust (still legal for a while). I'll be interested in how they compare.

[digger]

Crank driven fan is already deleted (I rewired the existing fan a la Euro M3s, with the OE brackets)
Power steering is already deleted
Spec E30 Exhaust is already installed

The price is very right on the Dyno time - I am splitting it with another Spec E30 guy (so we can compare numbers back to back on the same dyno) and it is 200 bucks total for the day, including any tuning needed. So it isn't big bucks.

The car is low miles (85K) and spent 79K of those miles as an Automatic, so I think it is relatively fresh. But, as most know, the 1-2 HP on a spec car is worth a lot.

The car is right at the Spec weight. About all I can do is mess with the alignment and make sure my motor isn't down on power as compared to the field. Then, there is only one remaining weak link....
:)

So - Injectors
FPR
AFM (confirm vane is free and the pot is good)

Not much to play with - the other car getting the dyno time still has A/C, Power Steering and a non-Spec exhaust (still legal for a while). I'll be interested in how they compare.

Its very hard to pick up any small changes in WHP on the dyno as there are heaps of variables that will alter the whp value and these include tyre pressure, oil temp, coolant temp, transmission and difff oil temps, IAT etc so you might want to monitor as many of those as practically possible to know for sure a change in whp is a true change for the better. If you register an improvement always put the setting back to where they were to check that it was the change that made the better power.

Make sure your injectors, plugs, coil wires, filters etc are all good.

You might want to look at do any tuning w/o the O2 sensor connected and might want to reset the ECU to get back to the baseline maps.

W/O changing the chip there is fuel pressure and AFM spring tension adjustments that can be made, these are not ideal methods but you may get some small benefit.

[jblack]

Its very hard to pick up any small changes in WHP on the dyno as there are heaps of variables that will alter the whp value and these include tyre pressure, oil temp, coolant temp, transmission and diff oil temps, IAT etc so you might want to monitor as many of those as practically possible to know for sure a change in whp is a true change for the better. If you register an improvement always put the setting back to where they were to check that it was the change that made the better power.

Make sure your injectors, plugs, coil wires, filters etc are all good.

You might want to look at do any tuning w/o the O2 sensor connected and might want to reset the ECU to get back to the baseline maps.

W/O changing the chip there is fuel pressure and AFM spring tension adjustments that can be made, these are not ideal methods but you may get some small benefit.

Good post - I appreciate it!

I think I'll pick up a new fuel and air filter on the way out there. I have spare plugs I can take out of my spares.

I have a spare ECU that I want tested too - see if there is any difference between them.

I don't understand the O2 sensor comment - do you mean leave it permanently disconnected? If so - that is not going to be legal - or do you mean just during tuning?

Thanks!

[digger]

Good post - I appreciate it!

I think I'll pick up a new fuel and air filter on the way out there. I have spare plugs I can take out of my spares.

I have a spare ECU that I want tested too - see if there is any difference between them.

I don't understand the O2 sensor comment - do you mean leave it permanently disconnected? If so - that is not going to be legal - or do you mean just during tuning?

Thanks!

Over time O2 sensor can upset the AFR even when in open loop at WOT because overall correction factors can sometimes be applied. To get around this it might be an idea best not to have the O2 sensor connected while making adjustments. There is one guy in the whole of Oz who can do custom chips for the M20b25 and he always recommends not using the O2 fullstop because it can make unwanted changes/corrections. Its upto you really, it would be intersting to see how the AFR differs from what it is now compared to what it was at the factory which can be obtained by reseting the ECU(disconnect the battery for a short while).

On a similar note take a look at this old dyno plot with a 100% stock M20B25. Ignore the absolute numbers is this is an old dyno dynamics dyno uncorrected on a 100+F day. Blue and red curves were made with the car in the condition it arrived and green was after adjusting the M20AFM a few clicks(not 100% sure which way but i would guess tightening the tension).

I'll leave you to ponder whether the 6whp is from change of AFM setting (i.e. AFR, timing) bearing in mind at WOT the AFM is apparently not used, or is it due to lower IAT, lower oil temp, higher tyre pressures, or other transmission fluid temp differences. All runs were done within a matter of minutes. There was something at play but i am not sure what it was!!!

If you aren't using a K&N panel filter it might be a good idea to use one, despite it apparently flowing less than stock paper when connected to a blowervac my dyno testing showed 2-3% gain across the board.

[jblack]

Wow.

Just wow.

I'm glad I posted on this board about this!

Great stuff - thanks for the schooling on the O2 sensor - very infomative.

When I mentioned the filter thing, I was refering to the cone "hot air intake" that the dyno shows no increase in HP or TQ, but does sound good. Maybe I'll have him run without a filter for the tests (unless you guys think that will screw up).

[Sean]

Wow.

Just wow.

I'm glad I posted on this board about this!

Great stuff - thanks for the schooling on the O2 sensor - very infomative.

When I mentioned the filter thing, I was refering to the cone "hot air intake" that the dyno shows no increase in HP or TQ, but does sound good. Maybe I'll have him run without a filter for the tests (unless you guys think that will screw up).

Probably a good idea to run with the filter, because you'll have a truer example of how the car will be used. Just my .02 tho.

[jblack]

So....

Spark Plugs
Spark Plug Wires
Coil
Filters (I assume that is Air and Fuel)
Injectors
FPR
AFM (confirm vane is free and the pot is good)

I'll let him connect and disconnect the O2 sensor as needed

Again - this is great stuff. I promise to post results as soon as I can. Got to give back on this help - and I think it could be helpful to others here (if there is an E30 around without a M30 AFM or without an S52 swap here) :)

[Slick92GS-R]

Hey Jblack -- I met Natalie w/your car out at Homestead MS for the NASA event-- Very clean Example of e30 race car 4DOOR to be exact--

I did not have my car there but it was refereshing to see 3 E30's out there on Sunday
I was eager to hear the new spec E30 exhaust and it was marvelous.

Hopefully SpecE30 will trickle its way down to S Florida so we can all run ..


were you guys able to correct that brake light switch problem ?

[jblack]

Hey! Actually, you met Natalie with HER car - OK, OK, OUR car. You know the old married saying - what's mine is hers, what's hers is ...hers! J/K.

The brake light issue was as expected - a brake switch replacement needed. One of the clips had cracked off - easy fix. It will be back down in S. Florida for the next NASA event at Homestead.

With....Drum roll please..... More power!

The guys at Rennen Imports in Tampa did a nice job with it. HUGE UGLY flat-spot at 4500-5000 RPM, both Torque and Horsepower. Evil. Plus, my curve was very ugly compared to my other Spec E30 buddy who was getting Dynoed at the same time. He had a much smoother curve, and a tiny dip at the exact same place.

I went about searching the Internet, and I came up with the consensus answer... Bad AFM. I told the mechanic, he said he was way ahead of me - he had 3 other AFMs, already had swapped them into my car, and all of them had similar results - to differing degrees. Maybe the engine is just down on power, maybe this, maybe that....

I told him "OK" - asked him to adjust the valves while he had it, and I would deal with it.

He called this AM. Said he wasn't happy with his testing yesterday, so he ordered a brand new AFM in to make sure. Net is, he has 4 AFMs in the trash today - his 3 and my old one. The new AFM made the car look on the Dyno just kike the other Spec E30, with a couple more HP and Ft Lbs of torque than my friend (as to be expected - I have deleted my A/C and P/S, he has both still on with belts). The AFM has made the dip almost impercievable. If you have a flat spot somewhere in your power band, this is a good place to look.

The HP and TQ did not change much from the first runs with the bad AFM vs. the later runs with the good one. This makes sense to me too - wide open, the AFM does not really factor in. But, drivabilty and the curves are way improved.

Netting it out, on a DYNOmite, with SAE Correction:

HP - 156.7 at 5600 RPM
TQ - 147.0 at 5100 RPM

The Torque goes straight up and stays up, only varying a bit from 4K to red line
The HP goes up steadily from 3K to red line - nice smooth curve.

Hope this helps. To get the last ounce of power out of the engine, I am sending the injectors out to get rebuilt - $144 plus shipping for the set. I will probably find a Dynojet in the area so I can better compare numbers with the other guys.

[soul]

those are very good numbers! goodluck with everything!