New to TBI Tuning SBC 327 TBI

[kidsandjeep]

Hello All,

Hoping for some advice, I have a SBC 327 TBI'ed motor and it runs good, idles a bit high and the timing may need some help Currently a stock 1227747 ASDU ECM. The motor is in my 1951 Modified M38 (CJ3A) flat fender and it runs all over Moab in the heat but living in Colorado Springs when I run it up old Stage Rd, on some steep climbs up the mountain she overheats really bad, not sure if it is the the climbing, the drastic change in altitude, timing or the engine bay holding too much heat. I did add hood louvers and the engine doesn't overheat normal driving. I would like to try some different tunes in the ECM. I have the larger PIN Flash Proms and the Moates G2 adapter as well as a stock ECM once I get the tune right. Any "Bins" you all would suggest trying. Hope I got all that right, as I said totally new to tuning. I did delete the EGR on my TBI unit but as I said no other tuning changes.

Thanks all!

--Scott

[kidsandjeep]

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[MO LS Noobie]

Have you added any electric fans to get air flow across radiator at rock crawling speeds? I do OBDII stuff, but there are some basic physics that apply.

[In-Tech]

Hiya,
This might help as a starting file :)

[kidsandjeep]

Hi, yes, I have an electric fan. Purchased with the most CFM I could get given the room I had. I should have pushed the motor further into the firewall but I didn't.

[kidsandjeep]

Thank you! I have a buddy helping me this week with soldering the chip parts from moates. Then I will see about programming chips. I have been reading here quite a bit about that process.

[MO LS Noobie]

I have a customer with a 383 SBC in a 80s model CJ. Had to try several different fans to get proper airflow. Worst-case scenario you could fog the front of the radiator with a water mist if you're only having problems at a certain point in the trail.

[kidsandjeep]

Thanks MO LS Noobie, that is a good tip on fogging the radiator, the steep climbs and rapid altitude change seem to be the biggest issue. I drove it last year all over Moab in July and never overheated or saw engine temps above 200. I stop before I boil over on Old Stage (last run I forgot my IR Temp Gauge so I couldn't check actual temp but gauge hit 245) and usually wait a few minutes to cool down then climb some more, repeat. I can try the misting next time if tuning doesn't work I am also going to raise the rear of my engine hood slightly to maybe remove trapped heat. I have hood louvers but maybe not enough. I can try different fans too but need a very thin fan due to space issues between the radiator and water pump. I would take a recommendation on a real good electric fan if anyone has one.

[Fast355]

Thanks MO LS Noobie, that is a good tip on fogging the radiator, the steep climbs and rapid altitude change seem to be the biggest issue. I drove it last year all over Moab in July and never overheated or saw engine temps above 200. I stop before I boil over on Old Stage (last run I forgot my IR Temp Gauge so I couldn't check actual temp but gauge hit 245) and usually wait a few minutes to cool down then climb some more, repeat. I can try the misting next time if tuning doesn't work I am also going to raise the rear of my engine hood slightly to maybe remove trapped heat. I have hood louvers but maybe not enough. I can try different fans too but need a very thin fan due to space issues between the radiator and water pump. I would take a recommendation on a real good electric fan if anyone has one.

Ditch the electric fan and use a mechanical fan with a universal shroud. Electrics will never cool in that kind of environment. I had a massive 34x17" dual core radiator and dual electric fans on my Express van and it still overheated. Put a clutch fan on it and it runs cool. I converted my 1980 Corvette to a TBI B-car accessory setup and only had room for a thin flex fan on a 3/4" spacer, but I had zero cooling issues with that car running the AC.

[Fast355]

For something working hard at higher engine speeds and lower vehicle speeds you want a fairly agressively pitched fan, not a flex fan or some kind of thing bladed race fan. I worked on a L31 350 in a Kohler generator that had a fan about 18" in diameter but similar construction. It ran full load at 1,800 rpm and never ran over 210F on a 115F day with a very modestly sized radiator and matching shroud. Radiator was 20" x 20" and 1" thick core.

https://www.amazon.com/Mechanical-Steel-Cooling-Fan-Inch/dp/B07N7RSQQ5/ref=asc_df_B07N7RSQQ5/?tag=hyprod-20&linkCode=df0&hvadid=658382491081&hvpos=&hvnetw=g&hvrand=14677791305894670918&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9026906&hvtargid=pla-2062429429103&psc=1&gclid=CjwKCAjwseSoBhBXEiwA9iZtxjLK-rar-8sohFqhL_tgkhOnp6vg0PuKbAAbj6AC5iDjvchaw8mt9RoCzJA QAvD_BwE

[MO LS Noobie]

I can try different fans too but need a very thin fan due to space issues between the radiator and water pump. I would take a recommendation on a real good electric fan if anyone has one.[/QUOTE]
If the tune doesn't take care of it, I have used a 2 gallon garden sprayer with the nozzle set on mist. As far as electric fans, what is your radiator core dimensions, and do you have room in front for a pusher fan also? I run a 6.7 L LS and the stock dual electric fan set up keeps it around 200° with the air conditioning running in the ambient temperature over 100°.
Remember there are many ways to skin a cat, but a cup of gasoline and a match are by far the safest and quickest.

[Sledhead2]

Ok I am going to ask some questions in trying to learn some stuff.

1) have you always ran TBI on this build?
2) Did you ever just run a carb and HEI? Did you ever take it climbing in Colorado with just carb set up? did it get hot?
3) Did you ever make a data log when climbing and it gets hot? I would be curious to see the timing and A/F Ratio when climbing

I only ask because like you, I am trying to figure out if your running into a timing and fuel mix issue or an air flow thru the radiator or both. But which one do you start looking at first

You say it does not get hot at Moab, this has me thinking your driving at say 30mph or more and thus have air flow, plus your at a lower altitude. So everything in the tune might be in harmony.

I know nothing about climbing, but it sounds like your in lower gears, higher rpms, and barely moving (thus no air flow) and climbing in altitude (which is going to play heck with timing and a/f ratios.

I wonder if you are going to need to burn a custom chip and swap them out depending on the fun trip you have planned.

Maybe make a climbing chip that has a completely different fuel table and timing table set up for thin air, and a daily driver chip for playing in Moab.

[kidsandjeep]

Hi,
1) I have always had TBI on this build.
2) Never took it climbing Old Stage Rd with any other setup
3)I haven't data logged while climbing but that is next.

I just got an ECM setup to start programming different tunes, the stock chip in the current ECM (ASDU) may not be optimal for the SBC 327 and TH350 Trans (4.56 gears, 35" tires, thinking about a 5.13 regear). So I am going to play around with tunes any input any recommendations on what to start with would be appreciated! The trails I ran in the summer at Moab were slow speeds, high outdoor temperatures. If anything on Old Stage Road here in Colorado I am running much faster (25MPH average I could go faster) then when I am rock crawling (under 5mph) so air should be moving better. I am curious on whether custom tuning fixes my climbing issues. I am totally a newb to programming. Altitude may be a factor also, the road is pretty steep running next to Pikes Peak a 14ner, climbing into the mountains. I have tried shutting down and maybe that resets the ECM? Do I have to disconnect the battery to reset the ECM? I haven't done that. I also think my current electric fan may be under powered for this climbing (odd that it cools in other situations) and as you say the A/F and timing are also problematic. I have been looking at a Perma Cool Hi Performance Electric fan as an option. It's a tight fit in the engine bay but I maybe an offset 14in Perma Cool (vs a 17" that even at 3.75" width won't fit with the water pump) and custom fan shroud. The 14" permacool is rated at 3300 CFM. I hope to start programming custom chips in the next few weeks. Thanks for the comments.

[kidsandjeep]

Ditch the electric fan and use a mechanical fan with a universal shroud. Electrics will never cool in that kind of environment. I had a massive 34x17" dual core radiator and dual electric fans on my Express van and it still overheated. Put a clutch fan on it and it runs cool. I converted my 1980 Corvette to a TBI B-car accessory setup and only had room for a thin flex fan on a 3/4" spacer, but I had zero cooling issues with that car running the AC.
Dumb question but can I run the flex fan without a clutch? If I remember right the clutch plus fan sent me down the electric fan route in the first place.

[kidsandjeep]

I can try different fans too but need a very thin fan due to space issues between the radiator and water pump. I would take a recommendation on a real good electric fan if anyone has one.
If the tune doesn't take care of it, I have used a 2 gallon garden sprayer with the nozzle set on mist. As far as electric fans, what is your radiator core dimensions, and do you have room in front for a pusher fan also? I run a 6.7 L LS and the stock dual electric fan set up keeps it around 200° with the air conditioning running in the ambient temperature over 100°.
Remember there are many ways to skin a cat, but a cup of gasoline and a match are by far the safest and quickest.[/QUOTE] The radiator is like 22" X 20" aluminum, it was all I could fit and no room for a pusher. In those moments I am waiting for it to cool so I can keep going I ponder the cup of gasoline and match. HA!

[Fast355]

Dumb question but can I run the flex fan without a clutch? If I remember right the clutch plus fan sent me down the electric fan route in the first place.

If the engine is at RPM and you are nearly stationary, a flex fan is the wrong fan for the application. Saw somebody put one of those on a stationary 350 on a generator and kept wondering why it overheated under load. You want a fixed blade fan for maximum airflow.

[MO LS Noobie]

Agree with fixed fan, no fan clutch for max airflow, but most power loss.

I think you are on the right track with the 3300 CFM electric setup, if it is an airflow issue. Had a mostly stock 75 Corvette in the shop that we wound up with a dual fan, one 14" and one 12" with properly modified shroud because of fitment issues, to finally keep it cool when extended idling, in gear, with A/C on. Calculated airflow was 4200 CFM.

I never ran a flex fan with a clutch, bolt directly to water pump with only enough spacer to clear fan belts, etc. Make sure you have proper spacing to shroud, if applicable. I have had best results with this type

https://www.amazon.com/Derale-17018-Stainless-Standard-Rotation/dp/B000CN4Y20/ref=sr_1_5?crid=3ORHSPAUX85B3&keywords=flex+fan&qid=1699619904&sprefix=flex+fan%2Caps%2C139&sr=8-5

Short style water pump gets you an extra 1/2" clearance if you have a long style.

[Fast355]

Agree with fixed fan, no fan clutch for max airflow, but most power loss.

I think you are on the right track with the 3300 CFM electric setup, if it is an airflow issue. Had a mostly stock 75 Corvette in the shop that we wound up with a dual fan, one 14" and one 12" with properly modified shroud because of fitment issues, to finally keep it cool when extended idling, in gear, with A/C on. Calculated airflow was 4200 CFM.

I never ran a flex fan with a clutch, bolt directly to water pump with only enough spacer to clear fan belts, etc. Make sure you have proper spacing to shroud, if applicable. I have had best results with this type

https://www.amazon.com/Derale-17018-Stainless-Standard-Rotation/dp/B000CN4Y20/ref=sr_1_5?crid=3ORHSPAUX85B3&keywords=flex+fan&qid=1699619904&sprefix=flex+fan%2Caps%2C139&sr=8-5

Short style water pump gets you an extra 1/2" clearance if you have a long style.

I have run 6,000 cfm of electric with a 454 34 x 17 x 2" core radiator and it would not keep a 350 under load cool.

[Sledhead2]

KidsandJeeps, I think you are fighting a tuning issues (timing and AF ratio) for climbing mountains, not an air flow thru rad.

You stated "The trails I ran in the summer at Moab were slow speeds, high outdoor temperatures." you said speeds slower then going up (25mph) mountain. I am thinking your speeds were 15mph or less in 90's+ heat and it doesn't run hot. Thus I am thinking it has to do with thin air. Moab is at 4000' and Colorado is at 6000' and from there you start to go higher. Also the air gets colder the higher you go.

I think, I would start with a data log driving up the mountain to see if you can see a point of where she start to get warm related to elevation, from there I would look at Air Fuel Ratio and timing.

My quick thought was you need more timing and less fuel, so a quick google look up found these post.

https://www.google.com/search?q=effects+of+high+altitude+on+timing+on+hig h+performance+engines&sca_esv=581969934&rlz=1C1CHBF_enUS1056US1056&ei=K1xSZfuxDPinqtsPr_mPSA&oq=effects+of+high+altitude+on+timing+high+perform ance+engines&gs_lp=Egxnd3Mtd2l6LXNlcnAiO2VmZmVjdHMgb2YgaGlnaCBh bHRpdHVkZSBvbiB0aW1pbmcgaGlnaCBwZXJmb3JtYW5jZSBlbm dpbmVzKgIIADIIECEYoAEYwwQyCBAhGKABGMMESNxfUMAXWKwq cAF4AZABAJgBaKABwgSqAQM2LjG4AQHIAQD4AQHCAgoQABhHGN YEGLADwgIKECEYoAEYwwQYCuIDBBgAIEGIBgGQBgg&sclient=gws-wiz-serp

Hope this helps

[dave w]

KidsandJeeps, I think you are fighting a tuning issues (timing and AF ratio) for climbing mountains, not an air flow thru rad.

You stated "The trails I ran in the summer at Moab were slow speeds, high outdoor temperatures." you said speeds slower then going up (25mph) mountain. I am thinking your speeds were 15mph or less in 90's+ heat and it doesn't run hot. Thus I am thinking it has to do with thin air. Moab is at 4000' and Colorado is at 6000' and from there you start to go higher. Also the air gets colder the higher you go.

I think, I would start with a data log driving up the mountain to see if you can see a point of where she start to get warm related to elevation, from there I would look at Air Fuel Ratio and timing.

My quick thought was you need more timing and less fuel, so a quick google look up found these post.

https://www.google.com/search?q=effects+of+high+altitude+on+timing+on+hig h+performance+engines&sca_esv=581969934&rlz=1C1CHBF_enUS1056US1056&ei=K1xSZfuxDPinqtsPr_mPSA&oq=effects+of+high+altitude+on+timing+high+perform ance+engines&gs_lp=Egxnd3Mtd2l6LXNlcnAiO2VmZmVjdHMgb2YgaGlnaCBh bHRpdHVkZSBvbiB0aW1pbmcgaGlnaCBwZXJmb3JtYW5jZSBlbm dpbmVzKgIIADIIECEYoAEYwwQyCBAhGKABGMMESNxfUMAXWKwq cAF4AZABAJgBaKABwgSqAQM2LjG4AQHIAQD4AQHCAgoQABhHGN YEGLADwgIKECEYoAEYwwQYCuIDBBgAIEGIBgGQBgg&sclient=gws-wiz-serp

Hope this helps


Screen captures from a data log: fuel rich / lean and spark advance.

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[scooterwrench]

If you are running antifreeze/coolant you may want to go to straight distilled water. Antifreeze/coolant raises the boiling point and freezing point of water but it's the water that cools the engine.

[Sledhead2]

Dave W what do them jpgs reference? are they from a tune you did for a high altitude? or are them a starting point for Jeepsandkids based on your experience?

Also Jeepsandkids, I noticed something in the jpegs Dave W posted, all the titles or headers call out a wide band O2 sensor. The point being if you don't have an wide band O2 installed you should install one. If i have learned anything on this site it is a wide band is ALMOST a must have to start.

[Fast355]

Dave W what do them jpgs reference? are they from a tune you did for a high altitude? or are them a starting point for Jeepsandkids based on your experience?

Also Jeepsandkids, I noticed something in the jpegs Dave W posted, all the titles or headers call out a wide band O2 sensor. The point being if you don't have an wide band O2 installed you should install one. If i have learned anything on this site it is a wide band is ALMOST a must have to start.

I find a wideband mostly irrelevant myself except for tuning transition fuel. I have very seldom used them in 20 years. I find the fueling right where it needs to be when I tune using narrowbands alone. I hook a wideband up and the tuning based on narrowbands is right where it needs to be. The wideband is helpful to me in one place, because it is quicker responding for transitions though. I can use 02 sensor voltage to get the fueling as close as any wideband at WOT and fuel trims to get the part-throttle fueling done. Start with idle amd part-throttle tuning using fuel trims, get the VE table where it needs to be and the WOT falls into place pretty easily. There is very little power difference between 11:1 and 13:1. I shoot for 12:1 at peak torque and 12.5:1 at peak HP. It is safe and it works. Stay a bit on the rich side with the narrowbands at 880+ mv at peak HP and 920+ at peak torque. Staying on the rich side helps keep the combustion chambers and spark plugs cooler, basically eliminating pre-ignition.

[dave w]

Dave W what do them jpgs reference? are they from a tune you did for a high altitude? or are them a starting point for Jeepsandkids based on your experience?

Also Jeepsandkids, I noticed something in the jpegs Dave W posted, all the titles or headers call out a wide band O2 sensor. The point being if you don't have an wide band O2 installed you should install one. If i have learned anything on this site it is a wide band is ALMOST a must have to start.

I did some data analysis AFR vs. BLM. Using the Myth Busters way of collecting data the "Control Vehicle" was data logged while being driven to and from work for 5 weekdays. All 10 data logs (.CSV files) were combined into ONE very large file.

I'm of the opinion, Good Data will provide a Good Tune. It's debatable AFR vs. BLM. Sometimes the computer will lock the BLM's at 128, which provides the ultimate tuning frustrations.:mad1:

All things considered, the Smiles per Mile favors AFR.

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[1project2many]

I would agree that data collection is helpful. I would be confirming BARO updates when increasing altitude. BARO is determined at key on / engine off and during some WOT operation. BARO represents barometric pressure where the engine is operating. If BARO is off, other values calculated using BARO will be incorrect.

Tuning options can include adding fuel and reducing timing as the engine gets hotter. These tricks usually help reduce engine temperature at the expense of fuel economy. In tuning everything is a balance of one kind or another.

Engine oil temperature can be used to help determine whether or not spark advance is correct. As spark advance increases, so does engine oil temp. And oil temp increases faster than coolant temp. Start your run with engine at operating temp and keep an eye on oil temp. If you see rapid increase in oil temp before a change in coolant temp, it may indicate too much spark advance.

Luckily, the old SBC uses a moveable distributor. There's nothing that says you can't try moving the distributor 2-4 degrees retarded before going up the hill. If the cooling problem inproves then you might benefit from a tune that removes some spark advance.

What octane fuel are you running? At 3500 - 4000 feet in MT I found that pulling timing a couple of degrees helped a bunch of engines. GM said it wouldn't but dang if the rancher's trucks didn't run a bit cooler. We had 85.5 octane fuel as the base level, then 87 and 89.