• Protip: Profile posts are public! Use Conversations to message other members privately. Everyone can see the content of a profile post.

What are optimum intake temps for turbo NSX's?

EAC

Legendary Member
Joined
26 July 2010
Messages
2,398
Location
Wildwood, MO
After a day on the dyno and intake temps in the 160's, I'm thinking I need to address this asap.

I know that with my previous turbo RX7's, it liked to be around 100.

What temperature do Turbo NSX's like?
 
You should be able to get around 20 to 30 degrees over ambient with all the meth your spraying.
 
You should be able to get around 20 to 30 degrees over ambient with all the meth your spraying.

Yeah, I wish. We didn't start spraying until it was heat soaked. By then, it was a lost cause.


We were making back to back pulls for 5 hours. It was 91 degrees inside.


Now, I'm just wondering how the car will react when it's not heat soaked? :confused:
 
In all seriousness I was usually around 20-30 over ambient. When I had BBSC with no meth temps would get into the 160-180 range using the same exact aftercooler setup.....so the 160 number makes good sense as it was in August when I had it.
 
I just saw 140-150F after 2 pulls through top of 4th (see my dream thread in the general owner section).
 
I just saw 140-150F after 2 pulls through top of 4th (see my dream thread in the general owner section).

Even at 140-150, isn't that still a little on the high side?
 
Even at 140-150, isn't that still a little on the high side?

It is all relative, the lower the better but in a mid-engine car the engine placement and airflow restrictions are limiting what can be done. A stock NSX will run IAT's in the 120-160's on a 90 degree day in normal driving conditions, the more you rev the motor the lower the IAT's will be on a N/A car as the intake airflow is the cooling method to pull out the heat soak of the intake form the higher engine bay temps.

The FI cars do not get the benifit of reducing heat soak with the increased intake air flow as the pressurized air is already heated above ambient. So with the CTSC you will see much higher IAT's, if you do nothing to address the temps the CTSC will see 160-190's on a 90 degree day and when you doing more spirited driving the temps raise even more and on the track 220-250's is common.

What you want is the lowest possible IAT's, without water/meth and a very well designed water to air you may be able to get down to 20-30 degrees above ambient temps add in the water/meth and your temps will drop very close to ambient or even cooler. You can actually get there with just water injection but the meth adds another layer of knock protection and raises the octane of the fuel mixture.

From what I can tell by logging my car the OEM ECU will start adding fuel around 120 degrees and pulling timing around 130 degrees, but this is not always done and the amount of changes it is making is hard to measure without pulling the engine and running on an engine dyno with very controlled loads to test what the ECU is doing. These numbers are based on an '04's ECU and I think the 95-96 ECUs are much closer to the 91-94 ECU's in terms of code and operation. The 97 and newers are different in the way they act in terms of fuel trims and open/closed loop operations.

Dave
 
It is all relative, the lower the better but in a mid-engine car the engine placement and airflow restrictions are limiting what can be done.......

This is one of the reasons why I did the Ceramic thermal barrier and dissipation coatings for my engine build.......
 
Are you still running a stock IAT sensors or an aftermarket one, also is the sensor before or after the nozzle
 
Are you still running a stock IAT sensors or an aftermarket one, also is the sensor before or after the nozzle

I'm still running the stock IAT sensor. It's after the Meth Nozzle.

One thing I forgot to mention, the dumbass that I am..... wasn't running water through my air to water intercooler while we were dynoing. :eek:
 
So did u burn out the water pump running it dry?

I never got a chance to even hook up the pump and lines. I honestly figured the Meth would do a good enough job until I had time to finish the Water to Air intercooler plumbing.
 
HOW many runs are we talking over a 5 hour period?

I have no idea, but alot. We started at 11am and ended at 4pm. Once finished, we took it out on the street for some final monitoring.

We had some downtime though, software issues, meth issues and my laptop battery dying. My fault...
 
So......you didn't hook up the aftercooler and you aren't spraying meth or putting fans on the car:confused::confused::confused::confused:.....and you did back to back pulls for five hours?
 
So......you didn't hook up the aftercooler and you aren't spraying meth or putting fans on the car:confused::confused::confused::confused:.....and you did back to back pulls for five hours?

Yes, I was spraying 100% Meth (.0315 nozzle @ 50% duty cycle). I thought that would chill things enough until I had time to plumb everything up. Apparently not? :eek:
 
what size hot side a/r you running, with meth and those temps :eek: i would say that heat soak played a large factor, but this is the joy of F.I., remind you of that FD, I have been here with my cars. In my Z I had to run dei cry02 intake and intercooler sprayers, with c02 not with nitrous, I had a 100kg tank in my garage i could fill it on my own. But thats more money.
 
Yes, I was spraying 100% Meth (.0315 nozzle @ 50% duty cycle). I thought that would chill things enough until I had time to plumb everything up. Apparently not? :eek:

Water is what absorbs heat not the Meth alone. You should not run more than 50% Meth because there is no benefit. I wouldn't have someone tune your car without knowing about Meth injection and using no fans. This is how motors blow and people blame it on too much boost.
 
Water is what absorbs heat not the Meth alone. You should not run more than 50% Meth because there is no benefit. I wouldn't have someone tune your car without knowing about Meth injection and using no fans. This is how motors blow and people blame it on too much boost.

OK Guys everyone needs to know more data to make any other assumptions.

1. there was a large fan on the front radiator the entire time, engine coolant temps never exceded normal operating temps.

2. the engine hatch was open the entire time to aid in engine heat removal

3. part of the tune was to test the effectiveness his meth system has at controlling IAT's. To test for this you have to heat soak the car to normal under hood real world driving temps then try and control them with the cooling agent.

4. IAT never exceeded 160 degrees in a pull and once that temp was reached we were able to drop them to 143-155 degrees with the use of the Meth.

5. Once the engine bay was heat soaked a 2nd fan was added to blow across the engine bay and remove some more heat but not all of the heat, no one drives around with a big fan hanging off the side of the car and most mid engine cars will have higher underhood temps than front engine cars.

We could have never let the car see IAT's much above ambient and just tuned for those conditions, but unless Eric trailers his car to the track, runs the 1/4 mile and shuts down, those IAT's are not realistic for real world driving conditions. With any tune expecially the NSX and the F/IC you have to tune for what the ECU is doing not what you want it to do.

The OEM program is aggressive about adding fuel and reducing timing based on IAT as it should be. If we tune the car to 11:2 on Meth and then the car heat soaks to IAT above 150 the ECU will add lots of fuel and the AFR's will drop to 10:5:1 way to rich. In short bursts into boost with normal daily driving the meth is not used enough to control the IAT's and is there to reduce the risk of detonation. Stay in it for a longer period pulling through several gears while in boost and the IAT's come back down and the OEM ECU returns to normal fueling and the car starts to move lean, keep dropping the IAT's and the car may move leaner than your target 11.5-11.7:1 mark. We do not have a stand-a-lone here so you have to test for all conditions and take the average ideal condition as long as it is safe. With a stand-a-lone you have access to all the trims and can trim the fuel map based on IAT's the way you want to not the way the OEM program wants to.

Phase two of Eric's tune will have the water/air intercooler in place and functioning and the tune will be revised based on those real world diving IAT's. We may not have to make any changes but untill the data is in no one really knows.

I hope this helps to clear things up I am not attacking anyones opinion, but with only a few facts and I am sure the best intentions for the health of Eric's motors some of you guys made some very big assumptions. I am a firm believer in record data, tune, record data, tune, record data, tune, record data ...... I am not good enough of a tuner to tune a NSX in three pulls and test for as many variables as possible, maybe someone out there is but not me.

Dave
 
I was under the impression that you were going standalone. For lofty goals of 475+hp wouldn't that be the best option for precise control over everything?
 
Back
Top