timing and iat

[dan0617]

Originally Posted by realcanuk

I had my supercharger without meth for over a year.... saw about 140 at the end of a run. .

If you were running 12 psi on a top mount blower and no fancy intercooler tricks and no meth then you have an amazing blower to top out at 140 IAT at the end of a 1/4 mile pass. Guys running 7 psi are getting hotter than that on those blowers.

[realcanuk]

Originally Posted by dan0617

If you were running 12 psi on a top mount blower and no fancy intercooler tricks and no meth then you have an amazing blower to top out at 140 IAT at the end of a 1/4 mile pass. Guys running 7 psi are getting hotter than that on those blowers.

Most of my scans are on my laptop but here is an old one. No meth, a hot day in the middle of summer, but only 10-11 psi because belt was slipping.

147 IAT... guess I have an amazing blower....

I am not saying I run so much cooler... I just thought from all the PD blower bashing I see in forum, that centri's ran nice cool IAT's

[dan0617]

Originally Posted by realcanuk

Most of my scans are on my laptop but here is an old one. No meth, a hot day in the middle of summer, but only 10-11 psi because belt was slipping.

147 IAT... guess I have an amazing blower....

I am not saying I run so much cooler... I just thought from all the PD blower bashing I see in forum, that centri's ran nice cool IAT's

Awesome. Was this with the stock cam? If so I guess I should have bought an Edelbrock instead of a Vortech.

Odd that the IAT stayed dead flat at 147. I've never seen that happen. I always see it increase as the pull continues.

[realcanuk]

Originally Posted by dan0617

Awesome. Was this with the stock cam? If so I guess I should have bought an Edelbrock instead of a Vortech.

Odd that the IAT stayed dead flat at 147. I've never seen that happen. I always see it increase as the pull continues.

You are right about it staying the same. It is because the scale on the log was too wide to show the move. Here is another 10.60 run scaled a little better. That was with a stock cam. I have not taken my new setup to the track yet but it has been on the dyno twice... 5 or 6 pulls each time and IAT's maxed at appox 125.

This is not a centri / pd debate. I only commented on the high IAT's of the op because I dont see that high and although I have never owned a cenri, I read constant agruements that they are better because of less heat soak. I think his 160 IAT's are too high and there must be a reason behind it. That is all I was trying to point out.

[Unreal]

I've never seen over 130 IATs on my centri without meth. That is on 70-80 degree days.

[realcanuk]

Originally Posted by Unreal

I've never seen over 130 IATs on my centri without meth. That is on 70-80 degree days.

That's Unreal !!!

I couldnt resist. Thats more what I would expect from a centri !

[MANNYS2SS/RS]

Originally Posted by Unreal

I've never seen over 130 IATs on my centri without meth. That is on 70-80 degree days.

Same here and high 70's on meth. Driving around town in traffic it's 10 to 15 degrees above ambient temperature.

[Unreal]

Originally Posted by realcanuk

That's Unreal !!!

I couldnt resist. Thats more what I would expect from a centri !

Honestly your car is kind of a freak for PD blowers. A lot of them run 170-200+ when you really get on them. Keeping below 150 is great.

[realcanuk]

Originally Posted by Unreal

Honestly your car is kind of a freak for PD blowers. A lot of them run 170-200+ when you really get on them. Keeping below 150 is great.

I really dont know why it would be. When those logs done was factory eforce setup. Now I have a larger coolant tank but rest stock.
I am convinced a lot of the difference in pd/centri iat's is due to the placement of the sensor. If I moved my sensor into the intake airflow it would be much much lower. I cant prove that, but it only makes sense.

[dan0617]

Another interesting thing on that log is the coolant temp. I was told not to bother installing my 160 thermostat as the coolant temp would not be lower than with the stock stat orher than when warming up. I see here your coolant temp is 174 after a run. Maybe I should put in my 160 stat.

[realcanuk]

Originally Posted by dan0617

Another interesting thing on that log is the coolant temp. I was told not to bother installing my 160 thermostat as the coolant temp would not be lower than with the stock stat orher than when warming up. I see here your coolant temp is 174 after a run. Maybe I should put in my 160 stat.

My temp depends on few things. That run must have been after sitting for a bit. I run my fans with a switch between runs which allow me to start at laround 160. The fans cool it down very quickly. That first log I posted was probably a hot lap, with no cooldown in between runs.

[dan0617]

Originally Posted by realcanuk

You are right about it staying the same. It is because the scale on the log was too wide to show the move. Here is another 10.60 run scaled a little better. That was with a stock cam. I have not taken my new setup to the track yet but it has been on the dyno twice... 5 or 6 pulls each time and IAT's maxed at appox 125.

This is not a centri / pd debate. I only commented on the high IAT's of the op because I dont see that high and although I have never owned a cenri, I read constant agruements that they are better because of less heat soak. I think his 160 IAT's are too high and there must be a reason behind it. That is all I was trying to point out.

I just installed an ECS kit and many supporting mods. I too am seeing IAT's get to 160 on a back to back run on the street in 70 degree weather. First run I see about 140. My timing at 6200 rpm shift point is 11.5 when IAT hit 160. When IAt is cool, like at top of 2nd gear on first run, timing is 14.5.

[dan0617]

One point, timing coming down isn't necessarily killing power. Hotter mix ignites quicker so it needs less timing. Once the air enters the intake and piping, cooling it will not make it denser or give it more oxygen. I don't believe cooling the air (by meth or ???)will give it much benefit, unless you give it more oxygen, by increasing the boost. I'm already at 12 psi on a bone stock engine so I don't want more boost.

I guess my bottom line of thinking is meth or other means of cooling IAT is only worth it if you are willing to cram more air (oxygen) in. Cooling the air just to run more timing isn't going to make much more power, all else the same. It just needs more timing advance to ignite the cooler mix at the right time.

This is one of the reasons I like the Mr Freeze kit. Used it on my last Vortech setup and loved it. You are spraying the water/meth in the air cleaner, before the blower. The air gets cooled as the meth evaporates before and as it hits the impeller (must run a high percentage of meth to avoid any possibility of impeller erosion). Since the air is cooled on the intake side of the supercharger, it is denser air going in, with more oxygen, than if it was hot air. Also, the efficiency of the compressor is much better as the compressor is cooler. Also it is boost proportionate and there is no pump to fail.

I have actually thought about putting a Mr Freeze kit on my car, running 70% meth 30% water, then opening up the restrictor in the supercharger to lean it back out to proper AFR. Not sure how rich it would be up top but I wouldn't think I'd have to add more than a pound of boost to get the AFR back in line, and 1 more psi couldn't hurt, right?!?

[SRT10KLLR]

Here are some logs I took for comparison. This is with a Twin Turbo setup.


In This log IAT starts at 111* and end at 131*. 8:24 PM about 8PSI.


In This log IAT starts at 106* and end at 124*. 8:33 PM about 8PSI.


In This log IAT starts at 113* and end at 136*. 8:44 PM about 8PSI. Hottest of that day.


In This log IAT starts at 93* and end at 120*. 9:44 PM about 8PSI. Coldest of that day after an hour cooldown.


In This log IAT starts at 138* and end at 154*. 2:35 PM about 8-13PSI. I made a run then let it idle and heatsoak in the mid-day heat. I was testing the boost controller so I activated it in 4th but it was surging.