Ford lover, saves a 94' Z28

[grasshopperglock]

Heres the deal.

I drove down to a local mexican food place. Combo plate with tongue and beef fejitas. Less then two miles from my front door. Not enough for warm up.

Then to redbox across the street at 7/11. As I'm waiting, I let her idle to burn off water in the engine.

She got ridiculously hot. Didnt touch red on the factory gauge. Those gauges are junk anyhow. They're better then nothing but still suck.

The getting hot crap is stopping. Shes got a 180 degree themostat.


Heres what I did. I changed the fan turn on points in the ecm. The values in the pic are the new settings. My red neck self had visions of installing a switch on the dash, controlling fans. After I took a breath....forget that. This thing is automated. Let it do the work instead.

To compare the new settings to the old. Heres how much I dropped the threshold to when the fans come on. Do a little reverse math and thats what GM had it set at. Everything is in C. 185f for #1 fan. 190f for #2 fan are were I want temps to be when the fans come on.

Lasered the themohousing after the fans came on with the new settings. Temps shown in F. This is the temp after being cooled by the radiator. (Reverse flow LT1)

Lasered the radiator on the intake side. This is the temp of the water coming out the engine.

Heres what the gauge reads.

Now my fans are doing their job. I have no clue why GM set the turn on temp at 131 Celsius. That's not gonna work in a Texas summer. Unless changing head gaskets and milling heads are your thing. You gotta be careful adjusting even the smallest thing. The fan times between fans 1&2 can't run at the same time. Fan two shouldn't come on during the same temp as fan #1. My understanding is it confuses the ecm causing it to change other variables. Make no mistake, tuning is in-depth.


I'm slowly convincing myself to buy another set of heads. It's like $200 for two out at the junk yard. Early thick walled' jobs too. Somewhere GM cast an extra two pounds in the early heads. Heads closer to 98 are thinner and lighter.


I've ported heads before and those were cast iron. It's really easy if you're careful. Reports say HP increase is around 40 on ported LT1 heads Not bad for $200-300 bucks.




"Sent from a puff of smoke"

 

[grasshopperglock]

Too many folks have tipped their cards on here. TGT has some gun lovin', heavy duty, Texas gearheads running about. I welcome advice on any mod I do. Especially to the ECM.

 

[Brains]

You normally don't want the fans running at high MPH - you'll actually impede airflow through the radiator.

 

[grasshopperglock]

I was pondering that. My thoughts is the air going through the radiator at high speed would over speed the fan. I had visions of a blow gun stuck behind a box fan. It speeds the fan past the ability of the motor. My luck, burning the fan motor up.


I'm gonna return the high speed settings back to factory. Hysteresis hasn' been touched. It's still 3 degrees Celsius.


I'm gonna run her to Temple today and log her. I'm gonna tinker with shift timing. (Shift time vs %tips vs shift, normal, low alt). Once I install a "performance transmission button", Ill be able to adjust pretty aggressive shift timing in another table. Flick of the switch between cruising and balls out.


For now Ill see where the Tps% is, compared to my style of driving. I don't see me changing shift times below 37.5 tpS%. Times are currently set at~ 1-2, .725-.0775, 2-3 6.375, 3-4 6.375. Only 1-2 has different times. The rest, all have the same times.

Still doing research but I'm thinking lowering the 6.375s to the 3.000 range. If 37.5 %tps happens a lot during around the town driving. Ill go up the scale that doesn't happen unless I'm dogging the car.

I wanna be able to cruise without over necessarily stressing the trans and drive train.

 

[Brains]

You won't overspeed the fan, but the incoming higher speed air will end up slowing down as it hits the spinning fan, lowering the overall flow through the radiator.

Don't bother with the shift times. The 4L60e is just an electronically initiated shift version of the TH700R4 - the actual clutch apply/release timing is all still hydraulic. The times you see don't control the shift at all - they control engine torque output. The only way to make the transmission complete a gear change faster is to make physical changes in the trans. Those values control the duration of reduced ignition timing during the shifts to control perceived shift feel at part throttle, and to not overpower the clutches at higher throttle angles. Be careful doing anything on the 2-3 or 3-4 shifts, that high gear clutch pack is the achilles heel of the trans.

 

[grasshopperglock]

Fan temp settings. Highspeed fan #1, 140c. Thats close to 220f.

Fan 2, high speed set to 107. Thats close to 225f. There's no way a 3400-3700lbs, slick nose camaro, should reach those temps on the highway. Thats 3/4ton, towing a travel trailer temps. If she does hit those temps, I want the fans on regardless.

Shift time table.

"Sent from a puff of smoke"

 

[grasshopperglock]

You won't overspeed the fan, but the incoming higher speed air will end up slowing down as it hits the spinning fan, lowering the overall flow through the radiator.

Don't bother with the shift times. The 4L60e is just an electronically initiated shift version of the TH700R4 - the actual clutch apply/release timing is all still hydraulic. The times you see don't control the shift at all - they control engine torque output. The only way to make the transmission complete a gear change faster is to make physical changes in the trans. Those values control the duration of reduced ignition timing during the shifts to control perceived shift feel at part throttle, and to not overpower the clutches at higher throttle angles. Be careful doing anything on the 2-3 or 3-4 shifts, that high gear clutch pack is the achilles heel of the trans.

It's a monster SS trans, built to 4l65e with a stage two, trans go shift kit. 1675 stall converter. The highest hp rated 4l60e they sale. I'm with you though, I'm not changing 3-4 shift times. No real reason to.

 

[grasshopperglock]

Burning ecm with the new fan temps. I lowered the fuel cut off to 5750, resume at 5704. GM had it at like 5880...and she'll rack that high during a burn out. I only changed it at this time to keep me from redlining.


Once I get an idea of the power band through the gears. Ill set the fuel cut off accordingly with shift points. Just enough to where she doesn't bounce off the limiter during WOT shifts, yet doesn't twist to almost 6 grand.


These motors are only $350....but Damn it's a pita to pull. Just cause I don't have a cherry picker at this time.

 

[grasshopperglock]

I've also read a lot into changing trans line pressure. There's two trains of thought on it. Don't do it and do it.


Here's the deal on that. Shift timing adjusts the pressure through the process of the computer telling the trans to shift faster. However, since the trans has a shift kit. That in itself adjust pressure.


So that brings up the questions "Is the ecm telling the trans to up the pressure to take full advantage of the shift kit?"



If the pressure settings are changed, will the ecm just learn and adjust itself regardless of what I input? Changing other tables...


With the biggest issue being a mechanical pressure gauge is the only true way of knowing line pressure.

 

[mitchntx]

Might be different in Killeen, but in the greater DFW and Houston area, reverse flow aluminum heads for a 94-95 and 96-97 are like unicorn tears.
Most have been trashed because of overheating or Lloyd Elliot scooped them up.

But temps climbing like that while idling ... that sounds like a air pocket.
When you were burping the system, did you cycle the heater control?

 

[grasshopperglock]

Why no I didn't. Ill cycle the heater. But the system was burb'd 5 times. Coolant level in rad and overflow are right on.

The factory had the low speed fan 1 temp set at 270f. That was the lowest temp of all the settings too. She was just idling with zero flow across the radiator. It's hard to believe they had set the fans so high. It was a virgin factory tune. Seems awfully weird.


She doesn't overheat. She doesn't spit coolant either. She was getting toasty during idle. On the freeway, temps are fine.

 

[mitchntx]

Gotcha.

 

[grasshopperglock]

Gotcha.

Pick and pull has a gaggle of lt1 heads. They want like $79.876543 for each head, plus core charges of like $15 a head...then tax. I'm guessing $220 for two heads.


Buy me a die grinder bit and sand paper. Match the ports, clean up the under the intake valves. Smooth out the exhaust ports. Remove a few bumps, slick the chambers up. CC the chambers, get em all even.


Drop off the bare heads and the valves. Get those cut. A valve job is usually half the price if they don't have to take it apart and put it back together. Hell, Ill lap the valves myself cause Ill set the correct spring height. All they gotta do is turn 16 valves, cut 16 seats. I'm guessing I can get it done for around $50-$75 bucks. Besides, shops usually just stick shims under the springs, set it up to factory standards. "Good enough".....Which ain't worth paying for.


Best thing they're alloy. Way easier to smooth on vs cast iron. There's no reason to stick headers and roller rockers on it, until I have heads that match the mods.

 

[grasshopperglock]

Fans no worky with those settings. In post 585 showing the fan settings. The temps overlap. Fan 1 high speed is greater then the temp of the low speed of #2.


So, im gonna try it again. Ill burn these settings.

"Sent from a puff of smoke"

 

[grasshopperglock]

Might be different in Killeen, but in the greater DFW and Houston area, reverse flow aluminum heads for a 94-95 and 96-97 are like unicorn tears.
Most have been trashed because of overheating or Lloyd Elliot scooped them up.

But temps climbing like that while idling ... that sounds like a air pocket.
When you were burping the system, did you cycle the heater control?

Mitch, doesn't the heater core have water going through it regardless of the buttons on the dash? Theres no valve besides a one way flow thingy thats in the heater core circuit.


New new fan settings. Im gonna leave it at this. See how she does.

"Sent from a puff of smoke"

 

[mitchntx]

You know .. I believe you are correct.
It's all doors and gates now routing air.
Nevermind.

However, I bet those $80 LT1 heads are actually iron heads from LT1 Caprices, Roadmasters, etc.

What do the fans do when you turn on the AC compressor?
They both should run ... no low/high ...

 

[grasshopperglock]

You know .. I believe you are correct.
It's all doors and gates now routing air.
Nevermind.

However, I bet those $80 LT1 heads are actually iron heads from LT1 Caprices, Roadmasters, etc.

What do the fans do when you turn on the AC compressor?
They both should run ... no low/high ...

Hell if I know. Lol


They got it set up to where the fans come on in relation to a.c. line pressure. Not so much coolant temps. They do come on when you turn on the a.c.. I never checked if it's one or both. I need to look up what they mean by low speed. What mph it is. Same with high.

Right before programming the ecm, tuner cat runs a diagnostic( I think). Cause the fans come on for second. You can also hear the air pump cycle. I know the fans are working cuz it'll get an error code if they don't. No codes so far.



Here's the prices out there. The vortex jobs ain't much cheaper.

http://www.wrenchapart.com/price-list/

 

[grasshopperglock]

Hmmmm...let's see how the price of junk yard heads compares to new.


Out the door price for used heads, tax included $203.51

Shims,

http://m.summitracing.com/parts/nal-10212809. $1.97 each


Retainers

http://m.summitracing.com/parts/nal-19171528. $17.97 for 16


Springs


http://m.summitracing.com/parts/nal-12495494. $40.97 for 16


Valve stem seals, guessing $10-$20. I'll price it $15. They'll come in the gasket set. Rock Auto has fel pro $103.79.



Plus $75 to get things machined...



Compared to this,


Trick Flow LT1 heads, assembled.


http://m.summitracing.com/parts/tfs-30410008-m54. $850 each.


Doing the math....


$383.97 for ported factory, assembled.


Hmmm...that subtracted from $1700. That's $1,316.03 difference.


Replacing every valve(if the used heads needed it)...let's say $10 a valve. $160 for all 16.....


Used roller rockers usually sale for $150. Either 1.5 or 1.6. New they're about $250.....


The whole shebang with a hot cam,

http://m.summitracing.com/parts/nal-12480002

 

[grasshopperglock]

Went by the junk yard today. Found a set of lt1 heads on a 95 z28. This car wasn't in the premium side so the heads run $49 each.


Of course there's drama. Someone pulled the transmission cross member out and the trans is hanging. The car is set up on car rims. The motor is jammed up against the fire wall. No way to pull the heads.


I go to the office and ask for a tire jack. They have a pile of them. Figure raise the trans, pull the heads. They tell me that's there's no jacks allowed in the yard.

I explain what's going on. They suggest a chain crane. The only way I could have done it that way, is lift the car off the motor.....just to pull the heads.


I'm dumbfounded at this. I'm not pulling 3/4rds of the drive train for two core heads. Not worth it, not even if the heads were free. Being my usually rude, smart ass self. I tell them they can keep it. Don't want em' and walk straight out.


However there's good news on the horizon. I'm just gonna spray the motor. Found a NOS brand, full flow, wet nitrous kit...with lt1 throttle body plate.

Reverse look up, it's about a $650 kit. The guy wants less then half for it. Says nothing is missing. Asked why he pull it off the car.


Lol, he's a Ford guy with a 82 mustang, 383 stroker and decked out. He doesn't like Chevy and sold the firebird. The kit is being delivered to Harker Heights by one of his employees. If it checks out, this lt1 is gonna get JUICED.

 

[Brains]

150 shot all the way. Might want to drop a 255lph pump in the fuel tank though.