andyfloyd

How often do I pop my hood at Miatas at the Gap and people look and go..."OMG NO REROUTE???", its gonna overheat. I go ok well Im 38 years old and have been turboing miatas since 2001 and somehow I have never overheated my car. Now let me say this, I understand the thought behind the reroute and why its made. Is there a difference from cylinder #1 to #4? Yes, in my car its roughly 6-8*F hotter in the rear. But Im here to tell you that if you arent tracking your car and you are just driving the ***** off it on the street ( Think tail of the Dragon type stuff ) you literally dont need one.

How many cars did I see with a reroute overheating at the dragon....a bunch. All my buddies have no reroute and we checked coolant temps all weekend. I did not see hotter than 215* at the front and 222* at the rear of the engine and this is in summer heat driving up the dragon and driving the ***** off the car at 20psi and 350whp. If I cant overheat my car doing this and literally having the brakes smoking rolling into Killboy I dont see why everyone thinks this is necessary. Simplicity is a good thing, the stock cooling system can easily handle more than people think. If its a track car that is the ONLY time I think its really needed and even then the cars will still overheat without good ducting. Just want to see what people are gonna say, and thought this post could be interesting.

HarryB

AFAIK a reroute will NOT solve any overheating issues; you are changing nothing on the heat transfer from the cooling system to the environment side. More even cooling; sure, but I am in no position to judge how critical this is for a street car.

olderguy

iTrader: (19)

But it makes the front of the engine look much better without the thermostat neck. /s

andyfloyd

Does it though? Then you have a giant ugly hose running to the back of the engine which might be more ugly

Ted75zcar

iTrader: (2)

Yeah, common misconception to associate the reroute with overheating.

I have taken enough stock 100k+ mile motors apart to be confident that something is very different between #4 and #1. I have never taken a 100k+ mile reroute motor apart, so I can't definitely say that it is better, but the logic makes sense to me. When I have taken a lower mile reroute motor apart, I don't see much difference between 1 an 4. Interestingly, the blown stock motors I have purchased (3) all failed on 3 or 4.

I am curious if you have data to support such a small difference in temperature across the motor during a WOT pull. It has been many years since I looked at the temperature across the motor on a higher hp motor, but the delta front-to-back in my head is much greater, like along the lines of 50-100 degrees F or more. This also makes sense to me, we throw something like 30% of our heat energy into the coolant. If we are getting 100hp at the wheels, then we are putting around 100hp into the coolant. The only part of the equation where ducting plays in relates to the temp of the coolant entering the motor.

If you only have a 10 degree diff front to back, then your radiator is only reducing the temp of the coolant by 10 degrees. Does that sound right to you? That is like sub 10% efficiency for the radiator as a heat exchanger.

Edit: Would you look at that...

curly

iTrader: (25)

Yeah, IMO much cleaner, even with the huge hose running back to front. Coming from a lot of experience with BMWs, I’m guessing a number of people say they solved over heating issues by replacing X part simply because they replaced XYZ with new, properly working pieces. In our case X is the reroute, but YZ is a properly bled system, new thermostat, leaky hoses/joints sealed, etc.

andyfloyd

I am using a coolant temp gauge in the top rad hose and using the stock coolant temp sensor at the back of the head. Typically I will see +6-10* higher at the back of the head vs the front. I can't really log it bc my hydra can't use the temp sensor from the front so I watch the gauge and the laptop to get an idea. On a wot pull in 5th gear from 40mph up to redline I see 205* or so and at the front it's 195-198*. I too have pulled apart engines with over 200k and I didn't notice any major difference in the cylinders. I respect your opinion as I know you are quite intelligent probably more than I am lol.

andyfloyd

Yea I agree it's a whole bunch of things needed to not have a car overheat. Bleeding the system is a black art that I'm really good at and I bet a lot of people aren't and they have air pockets.

Ted75zcar

iTrader: (2)

Ok, I misunderstood the measurement you are taking. I thought you were taking essentially a "top tank vs bottom tank" measurement.

For science, do you have a plot of CLT from the beginning of a pull to the end of a pull? This is a topic I have been curious about for some time.

concealer404

iTrader: (3)

The way this is presented is like... beyond bizarre.

andyfloyd

Good.

How is it beyond bizarre though? What is beyond bizarre on the spectrum of words? What's the next word after bizarre?

andyfloyd

I can certainly get a plot for you.

Ted75zcar

iTrader: (2)

sweet, thanks!

sonofthehill

iTrader: (1)

I looked at a couple logs from Wednesday night. My OEM coolant sensor reads about 175-180 before a pass and about 185-190 after, peaks about 2 seconds after I let off. My chineseium intercooler sees a 50° delta on the same 11 second pass and peaks when I let off.

concealer404

iTrader: (3)

Anecdotal evidence strongly presented in a manner to suggest that cars without reroutes don't overheat, but cars with reroutes do.

Which... isn't the point of a reroute at all. Reroutes have zero bearing on overheating. It's just simply not what they're trying to correct. I would agree that your street car doesn't need a reroute. I would not agree that a message of "Hey ya'all you don't need reroutes" is a message that should be presented.

andyfloyd

I'll get some logs today.

andyfloyd

I gotcha. I'm just saying there are a lot of people with misconceptions about what the reroute actually does. It just evens out the coolant temps from front to back which is never a bad thing. It doesn't mean your car is going to overheat with a stock coolant system in place. I don't run one because I like simplicity and that's how my car is built. Stock coolant routing, stock IGN coils, etc. And it still makes 400.

I remember seeing a chart somewhere in this forum that said anywhere over 250hp you needed a different ignition setup. You can throw that out the window bc the stock stuff works.

Padlock

Based on my anecdotal evidence, upgraded radiators, radiator ducting, and reroutes are all a waste of money as long as you have hood vents and a kswap (regardless of street or track use)

emilio700

iTrader: (3)

Seems there might be some misconceptions about the efficacy of a reroute on a BP and what it actually does.

It absolutely improves cooling efficiency, defined as BTU's exchanged from coolant mass to atmosphere. The BP as delivered is like a house with one window open for a cooler breeze outside the house, but all other doors and windows closed. That end of the house cools a bit but the rest of the house stays hot. Adding a reroute is like opening an equal size window on the opposite side of the house. Everyone here has experienced the vast increase in airflow by taking advantage of the pressure differentials and increased contact with hot surfaces to cooler air. The whole house cools off and more heat is shuttled away.

The reroute is all about improved scavenging of all hot coolant and less about evening out CHT's. Or as I stated in the short Qmax video, like trying to cool the water in a glass of hot water by pouring cold water on top vs adding a drain at the bottom of the glass and dumping the entire contents quickly.

yossi126

iTrader: (6)

You just don't drive hard enough, in a hot enough environment to need a reroute.
Hell I needed a reroute when I was N/A. And that's doing track sessions at 30c degrees and more than 60% humidity.