What kind of intake temps are you guys seeing under a 4th gear pull? On a 80deg F day at a local track, I ran the car at 24psi on a Greddy T88 and I'm seeing temps that slowly increased to 145deg F (63deg C)

Does that seem hot?

Anthony

 

Hey Anthony,

I guess it depends. When you start your 4th geat pull, what is the starting temps? If you're seeing a huge jump in IAT, then it might pointing at the IC.

For comparision sake here is my experience.
When using a Apex'i FMIC with a GT40r and running a 40-140 (2nd gear through 5th) test run, I was seeing and average 15C increase in IAT.

When I switched out to a Greddy 3-Row FMIC, I see an a MAXIMUM 4C increase.

The comparison runs were logged at 21psi at varying ambient temps and the sample size for each setup was 10 runs.

Measuring outlet temps of your turbo and outlet temps of your IC have a benefit here.

I think the Apex'i FMIC is great for pressures below 17psi.

Beautiful car!

 

So what are the actual safe temps?
I've been told to ease up on the throttle if I see Intakes of 65*C or more.
Is that correct?

 

The ECU starts backing off the timing well before then. And adjusting the fuel.

Personally, I rarely see above 50C with a cool air intake and the IAT moved to the FMIC outlet. It would scare me to see more than 55C with my setup.

Keep an eye on your water, oil, and egt temps.

 

air to air IC's almost regardless of size when subject to proper testing will show BIG final charge temps even with high air speed (top of 4th gear pull).

i experiement 12+ years ago with this and still have my old Autronic ECU data log files that graphicaly show this problem.

Without resorting to nitrous or chilled water *artifical cooling methods* one of the most benificial things you can do is use water sparying on the IC core, I was doing this when I could not get water injection to work (lack of funds to upgrade ignition system and also using low grade jets) so I experiment alot with IC spraying, I went form 60+deg C charge to about 45deg C in same load conditions. Did use quite a bit of water though (no where near as efficient as putting into the motor where its more benificial).

F1 used water spraying in their highest HP days (1986) any serious team did it and its the only way they could arrive to 1350bhp for qualifying (BMW, with Benetton @ Monza GP) they sprayed up to 3lt of water per lap to keep charge temps under control and literaly had steam coming off the IC during qualy laps!
nedless to say water spraying and also water injection was banned from 1987 onwards.

Water is cheap and easy and you can use it to great effect, if you need some help PM me and will be happy to give you some ideas.

P.S. I went back to internal water injection and never bothered with water spraying the IC anymore as it solved all of the excessive water and oil temps and also the charge temp too, BUT the biggest thing was I gained in density increase of air flow capacity with pre turbo injection too which no other method will deliver for you

 

The problem I see also is the temperature probe is actually under the upper intake manifold. It will eventually get heat soaked and won't show real charge temps. The best is to move the sensor to the elbow before the throttle body or just after the intercooler.

On a side note does the power fc adjust timing or fuel accordingly or does it not use the temp probe for anything other than a reading?

R.K.

 

Assuming 30inHg compressor inlet pressure and 70% compressor efficiency, that would calculate to about 73% efficiency for the intercooler, which isn't bad. If it makes you feel any better, the manifold air temp would calculate to about 322F without the intercooler.

Just in case I made a mistake with my uber windows calculator and quick swags, you can crunch your own numbers with the help of the website below. Sorry, I am too lazy to do it myself.
http://www.gnttype.org/techarea/turbo/turboflow.html

 

CrazyRxy, most people pull the stock IAT out of that location. The PFC adjusts timing and fuel based on IAT. So if you're heatsoaked the UIM and the IAT is in there, and you drive through a nice cool patch of air...like through the mountains at night...not a good potential scenario. Most people aren't on that ragged of an edge of a tune, though.

Nice link, Evil Aviator. Thanks for that.

I just checked through my database of logs and I did hit the high 50's last summer. Looks like I was heat soaked from a few back to back runs with not enough cool down in between. My air intake is under the right headlight (mine don't flip.)

Tony

 

This might have been talked about before, but what about liuid to air intercoolers. My buddy is using one on this 42R boosted C5 vette and the IC stays dam cold. His intake temps on the dyno last night were 30*C and he was doing pulls for 6 hours.

 

I guess I should point out that you need to remove the "x 2" from the denominator of the Engine Volumetric Flow Equation because the rotary engine fires all of its displacement per revolution rather than 1/2 like a 4-stroke piston engine. Also, I found some mathematical errors in the examples, but so far the equations themselves seem ok. None of that affects the subject of this thread, though.

 

Anthony,

Your IAT sensor must be in the stock location.

Today, in 80 degree weather and after doing about a dozen runs in 3rd and 4th gear, I never went over 40C. I even went so far as to switch back to hot air intake (engine comparment only) and never went above 45C with the car moving. Average temperature was 37C.

My IAT is halfway between t-body and FMIC outlet.

I never went above 14psi...I was baseline tuning after re-doing the fuel system.

Tony

 

About a year later, I swapped intercoolers to the larger greddy 3 row, changed turbos and also moved the IAT sensor and still seeing high charge temps only in 4th gear. It slowly ramps up. Talking to a lot of drag racers, Rice Racing was right on the money. Tearbo2 is running a water to air and it seems the best bet right now.

Thanks Tony, at the lower boost levels I am fine. I should have mentioned earlier in the post that the boost levels were 30psi.

Good post!

Thanks, I think the intake temps get much higher after 30psi. I was doing a burnout, staging and then 1st - 4th gear pulls. I have since added water injection which is helping.

Thanks,

Anthony

 

Stock AIT sensor values are not a good indicator of the actual temperatures you are seeing. The stock AIT is a protected/closed type of sensor and does not change value quickly. In the thread below I have a link to an old log I did with the stock and GM sensors showing how slow the stock reacted.

https://www.rx7club.com/showthread.p...&highlight=ait

Your temperature increase are much higher than what most people are posting, believe that is because of the stock sensors that are being used. Also no matter how big your core is you will not get back to ambient temperature. No intercooler is 100% efficient. Though you might come close with AI.

PV=nRT at 15 psi you will see an increase of approximately of 150 f over ambient.

http://autospeed.com/cms/A_109789/article.html

Temperature Calculator for pressures
http://www.stealth316.com/2-turbotemp.htm

 

AnthonyNYC is not using stock sensors...

My brother's car (also not using stock sensors) also has a similiar problem with high air temps...

When you start pushing big boost heat starts to become a problem you normally would not see at only 15psi...

Your right you'll never be at ambient temps but i've seen some cars run 10 degrees over ambient with air/air intercoolers.. I would say that's pretty dam good.

 

I too have seen many claim single digits over ambient. When I have my v-mount fully vented I plan on testing this out as I always datalog pre/post IC.

 

Anthony I did a 3rd gear pull at 9.9 psi the other day I was seeing 62 F IAT The outside temp was about 65-70. Hotside 136 F Im spraying water and meth and running water to air and air to air see my water to air in the single turbo section

 

My IAT info:

Turbo - GT3574
Engine - S5 streetport
EMS - E6X (all GM sensors)
Intercooler - Godspeed FD core, custom piping/endtanks.

Following are without AI (which is ~600cc of pure water pre TB)
WOT @ 15psi 2nd through top of 4th = 55C
WOT @ 20psi 2nd through top of 4th = 59C

Following are with AI
WOT @ 15psi 2nd through top of 4th = 33C
WOT @ 20psi 2nd through top of 4th = 37C

Ambient was about 83F + or - a few degrees.

without AI it never goes above 60C even after back to back runs. With AI, sometimes it gets a little closer to 40C after back to back runs....although the funny thing is when the AI engages I usually see a large drop, then a steady rise. Sometimes it would go from 29-30C (cruising temp) down to 25-23C then start climbing as I stayed in boost.

All IAT numbers for runs were observed at the end of a run, starting temps would be a few degrees over ambient (usually right around 29-30C while cruising on a 20C day)

I/C core is fully ducted and I do have a fresh air feed above my headlight (its functional, not a gay scoop) pumping right into the air filter.