This past weekend of racing showed that I've a ProCharger tuning issue dealing with my manifold air temperature (MAT). The sensor is located in the throttle body above where the fuel is injected. It's reading the compressed air temp with the water/methanol in the mix.

Anyway, until this past weekend we haven't noticed a consistency issue with pulling timing in relation to MAT. Most of the time we usually have around 1* of timing being pulled & the MATs are right around 170*. This past weekend we were running/racing in 100*+ temps in the middle of the day. We were seeing MATs in the 200*-224* & the ECU was pulling between 4*-6* of timing; I could literally feel the timing being pulled in the middle of the run. The issue was the timing would be pulled at different parts of the track. The car was not consistent at all!

Below is the timing vs. MAT map. I built the map as a safety & might be able to not be so aggressive with pulling timing. I have seen no signs of detonation.

The car is down for the summer break & I have to figure out how to address the hot weather tune issue.

My base fuel is Sunoco GTX 100 octane street legal pump gas with water/methanol injection. The fuel mix probably has an effective range of 105 - 110 octane.

I'm leaning towards using canned/barrel E85 again, used it when I was NA. Any other ideas besides methanol as the base fuel?

2BKING

Someone can correct me if its wrong or not, but I have heard of racers unplugging the MAT sensor when say it is reading say 100* as a random temp, ohm the sensor and then install a resistor of the same value at the end of the cable instead of plugging it into the sensor, now your MAT is always the value of whatever resistor you choose.
Hope that makes sense

Edit, After re reading your original post I realized you are pulling that timing as a safety measure to prevent detonation so that resistor idea may not apply

This message has been edited. Last edited by: Big Steve,

Do you have a intercooler? If not maybe you need one with temps that hot even with the meth/water injection.

THIS FB Holley EFI group could have the answer/s you’re looking for.

quote:

Any other ideas besides methanol as the base fuel?

Are the TB injectors large enough to support methanol? DC less than 85%.

quote:

Originally posted by Big Steve:
Someone can correct me if its wrong or not, but I have heard of racers unplugging the MAT sensor when say it is reading say 100* as a random temp, ohm the sensor and then install a resistor of the same value at the end of the cable instead of plugging it into the sensor, now your MAT is always the value of whatever resistor you choose.
Hope that makes sense

Edit, After re reading your original post I realized you are pulling that timing as a safety measure to prevent detonation so that resistor idea may not apply

Big,

Yes, I'm pulling timing as a preventive measure. I can zero out this timing vs. MAT map out & use the base timing map to pull the timing, that should get rid of the timing/MAT map variable.

I have no intercooler & don't wish to use one.

I have way more MPH than needed for Pro & have to get rid of a bunch to judge the finish line better.

This tune was consistent until hitting this past weekend's hot weather. I don't plan on running in them conditions again & I skipped the 2nd race of the weekend. Too many cars breaking, crashing & spinning; didn't wish to beat up on my junk for the 2nd race. I shouldn't have run the 1st race.

2BKING

This message has been edited. Last edited by: B KING,

quote:

Originally posted by markemark:

quote:

Any other ideas besides methanol as the base fuel?

Are the TB injectors large enough to support methanol? DC less than 85%.

As far as I know the biggest injectors that will fit are 220 lb. that would work for E85.

I have (8) 120 lb. injectors now & the duty cycle is around 70%.

2BKING

quote:

Originally posted by Big Steve:
Do you have a intercooler? If not maybe you need one with temps that hot even with the meth/water injection.

I didn't fully reply to the 2nd sentence of your post. While the temps I gave are high, we have to remember the base fuel is injected after the sensor. I'm sure that's knocking the temp down a bunch.

Some racers are wanting me to put a sensor in the manifold. Yes, that would give a lower temp reading or should but it's just another number. The tune is safe for the high temps given but not consistent.

2BKING

The computer is doing what you have it programmed to do. When I tuned EFI cars - for those that raced them most of the temp correction stuff was locked out. Essentially doing what one of the posters said with using a resistor - but you can just zero out of the correction factors. Otherwise you will be chasing your tail in bracket racing.

Get your tune in a safe range and it might mean loading a separate program for different weather conditions. Kind of like guys that changing jets/bleeds in early spring, then again in summer heat, to again in the fall.

I do not know but to me it seems like you have three options. 1. Use less timing retard, less correction factors. 2. Use an intercooler to get temps cooler and more consistent. 3. Move temp sensor closer to port to get actual temp motor is seeing.

1. If you can feel it pulling timing then that indicates to me it is pulling way too much.
2. Why is the temps varying that much? What can be done to control temp better?
3. You are confident that actual temps are cooler after fuel is injected so why is system making adjustments from temps BEFORE the cooling fuel? The only temps that matter there is what motor actually sees. If you are not going to use an intercooler can you move the methanol injection further forward to increase cooling effect? The Procharger is creating the heat, can the water/ methanol injection be safely put in before the Procharger?

Is the Procharger cooled and lubricated with engine oil? If so what was your engine oil temp when this happened? If your engine oil was too hot then larger oil volume and cooler.

What was your water temp when the MAP temps went so high?

As I see it you already know you have too much heat and are pulling too much timing.

Up until this year I didn’t use an IAT programming in Speed Density. I wanted to switch to VE based and needed to add the IAT for this calculation.

When I researched IAT/ MAT it seemed that forced induction was better served with a MAT located in the manifold runner area. Mine being N/A the sensor located in the air filter housing was acceptable and viewing the results afterwards confirmed this.

quote:

Originally posted by Curly1:
I do not know but to me it seems like you have three options. 1. Use less timing retard, less correction factors. 2. Use an intercooler to get temps cooler and more consistent. 3. Move temp sensor closer to port to get actual temp motor is seeing.

1. If you can feel it pulling timing then that indicates to me it is pulling way too much.

I totally agree.

2. Why is the temps varying that much? What can be done to control temp better?

I used 2 different jet sizes in the water/meth. The jetting effects the RT & 60' another issue but have a solution.

3. You are confident that actual temps are cooler after fuel is injected so why is system making adjustments from temps BEFORE the cooling fuel? The only temps that matter there is what motor actually sees. If you are not going to use an intercooler can you move the methanol injection further forward to increase cooling effect? The Procharger is creating the heat, can the water/ methanol injection be safely put in before the Procharger?

It's making adjustments based on what I commanded in the table/map in the OP. The water/meth nozzle is feeding the inlet of the ProCharger, one of the most efficient places to inject.

Is the Procharger cooled and lubricated with engine oil? If so what was your engine oil temp when this happened? If your engine oil was too hot then larger oil volume and cooler.

Lube for the ProCharger is self-contained & gets air flow between each round.

What was your water temp when the MAP temps went so high?

The water temp stays around 160* during the run. The highest I saw it was 180* on the return to the pits.

As I see it you already know you have too much heat and are pulling too much timing.

I'm working on a hot tune plan & when finalized, I'll share.

Thanks everyone for your inputs, it's greatly appreciated!

I got caught with my pants down this past weekend. I'm glad I have a conservative tune-up & the only thing affected was the consistency of the car.

skidwnit hit the nail on the head with the correction factors for bracket racing. The issue is or was the timing vs. MAT table/map doing what I had commanded.

2BKING

quote:

Originally posted by markemark:
Up until this year I didn’t use an IAT programming in Speed Density. I wanted to switch to VE based and needed to add the IAT for this calculation.

When I researched IAT/ MAT it seemed that forced induction was better served with a MAT located in the manifold runner area. Mine being N/A the sensor located in the air filter housing was acceptable and viewing the results afterwards confirmed this.

M&M,

I should be calling my MAT sensor an IAT sensor but that's how Holley refers to it. As for moving the sensor to the intake manifold area, that's being considered. If I do move it, I hope to install the sensor out of direct fuel flow.

2BKING

^^^^^^ Yes, Holley lists this as MAT and when you research air sensors like Rife they’ll list them as IAT…… Same. Agreed, when I viewed sensors mounted in the intake they were not located in the runner.

quote:

Originally posted by B KING:
I should be calling my MAT sensor an IAT sensor but that's how Holley refers to it. As for moving the sensor to the intake manifold area, that's being considered. If I do move it, I hope to install the sensor out of direct fuel flow.

I decided & bought a new MAT & it will be mounted in the intake below the TBI.

While I'm not changing the tune. The mounting of the sensor in the new position should keep me out of the OP timing vs. MAT issue. If it doesn't, we'll start mixing in ethanol into our base fuel.

Our track has no bracket racing until Oct. So, our next appointment with the car is a hub dyno in Sept. I think we can find some more power with our current pulley/boost level & will take our smaller blower pulley with us also. What are we hoping to gain, mainly data but would like to find another 50-100 hp & keep the boost below 20 psi.

We are looking to start doing some limited no-prep heads-up/index racing on a 28 x 10.5 bias or 275/60 radial tire. We have some work to do but we are in the ballpark on the slow end of needed ET/MPH.

2BKING

quote:

Originally posted by B KING:

quote:

Originally posted by Curly1:
I do not know but to me it seems like you have three options. 1. Use less timing retard, less correction factors. 2. Use an intercooler to get temps cooler and more consistent. 3. Move temp sensor closer to port to get actual temp motor is seeing.

1. If you can feel it pulling timing then that indicates to me it is pulling way too much.

I totally agree.

2. Why is the temps varying that much? What can be done to control temp better?

I used 2 different jet sizes in the water/meth. The jetting effects the RT & 60' another issue but have a solution.

3. You are confident that actual temps are cooler after fuel is injected so why is system making adjustments from temps BEFORE the cooling fuel? The only temps that matter there is what motor actually sees. If you are not going to use an intercooler can you move the methanol injection further forward to increase cooling effect? The Procharger is creating the heat, can the water/ methanol injection be safely put in before the Procharger?

It's making adjustments based on what I commanded in the table/map in the OP. The water/meth nozzle is feeding the inlet of the ProCharger, one of the most efficient places to inject.

Is the Procharger cooled and lubricated with engine oil? If so what was your engine oil temp when this happened? If your engine oil was too hot then larger oil volume and cooler.

Lube for the ProCharger is self-contained & gets air flow between each round.

What was your water temp when the MAP temps went so high?

The water temp stays around 160* during the run. The highest I saw it was 180* on the return to the pits.

As I see it you already know you have too much heat and are pulling too much timing.

I'm working on a hot tune plan & when finalized, I'll share.

Thanks everyone for your inputs, it's greatly appreciated!

I got caught with my pants down this past weekend. I'm glad I have a conservative tune-up & the only thing affected was the consistency of the car.

skidwnit hit the nail on the head with the correction factors for bracket racing. The issue is or was the timing vs. MAT table/map doing what I had commanded.

2BKING

Good to hear it was an easy fix in table. I would review all the tables in detail. As mentioned you should limit them all down to AFR main table, and spark table.

If a change needs to occur - make the change and call it a new tune. This is actually why after 15+ years I have a carb and grid in my car vs some high end EFI system. Dont get me wrong the EFI stuff is very capable, but I found you just end up watering it down to the basics anyways - at least for bracket racing. Go fast stuff is entirely different story.

Not to mention - if something goes wrong with carb and simpler timing system it is easier to diagnose and change out.

quote:

Originally posted by B KING:
I decided & bought a new MAT & it will be mounted in the intake below the TBI.

While I'm not changing the tune. The mounting of the sensor in the new position should keep me out of the OP timing vs. MAT issue. If it doesn't, we'll start mixing in ethanol into our base fuel.

I got the new MAT sensor mounted in the intake & tested at idle. The MAT was reading 74* without the engine running. I started the engine & the temp immediately went down to 52*. I warmed up the car to as high as 190* coolant temp; the highest I saw the MAT was 64*.

The real test is when we put boost to it & that will hopefully be done is Sept. on the dyno. I'm hoping to have the MAT around 140* or lower under boost. As mentioned, we hope to be testing blending of additional ethanol into our base fuel that has 10% ethanol. Using the mixing calculator & ethanol testing kit we hope to have around 30% ethanol if needed.

2BKING