268 replies to this topic

[Rob Burgoon]

What was the temp at AFM?

 

Your previous test without wrapping, it was 85* outside and what temperature at throttle body?

 

 

Also, are these temps measured at full throttle or idle?

[Todd Green]

Todd, the AFM meter works well that way.

In my testing, running with 12.6@6000RPM AFR on a straight I was 14.8 in high G (1.4+) corners when it was flat. I wouldn't call that working well. (Of course it was equally as rich in the opposite handed corners.)
 

Thermocouple at filter, AFM and throttle body each position, different run.

So you didn't have the sensors inside the intake track and you only had one sensor that you moved at different times?

[James York]

Also, are these temps measured at full throttle or idle?

 

That was one of my thoughts also.  I didn't post in order to not to get into a pointless debate but the heat transfer coefficient across plastic is poor.  And and "race" conditions, I imagine the air is in the tube for no more than 1 second.  I could do the calculation, but I feel confident it is not possible for air to pick up 40F purely due to heating from flow across the tube from the AFM to the TB. 

 

The tube would have to be at temperatures significantly hotter than 40F higher to drive the heat transfer in that short of residence time.  If you touch your crossover tube, do you get burns, or does it just feel hot?  Note, i don't think a humans can stand to touch anything higher than 140F due to discomfort.

[Todd Green]

So 37 total votes on this informal poll. Not saying much for the 1.6 gang feeling this is a important issue.

How many active people do you think are on this forum? (Less than 300 have visited in the last month, under 150 have posted.) Add in that the poll is public, how many non 1.6'ers are going to vote against and risk the wrath of the rabid 1.6 gang? How many 1.6'ers don't vote so they don't appear to just be serving their own interests?  (How many 1.8'ers are fuming wondering why they don't get any love and don't at least have a poll to fix their rev limit issue?)  Then throw in the number of users who are new and/or don't feel qualified to vote as well as those who haven't raced for years but still hang around. Finally the poll doesn't represent some options and that has been expressed in the forums.

 

I guess I don't find the numbers to be surprising.  (Especially not if you consider only half the population votes in the US Presidential elections, which one might argue is a bit more important than BoP in Miatas. )

[davew]

If I may.....

 

We want to help the 1.6 without costing too much money and not making it an overdog.

 

Allow replacement of the rubber intake tube from the throttle body to the AFM. AFM must remain in the same basic location. Allow removal of the drivers side turn signal lense and headlamp (with mounting bucket). Allow air to be ducted from turn signal directly to AFM (RAM Air if you like). Barn doors must remain in place.

 

Allow all cars to upgrade to NB style suspension/control arms/steering.

 

Allow 0.5 compression ratio bump for 1.6. I would think we could get this from just a gasket.

 

Allow NA 1.6 chassis to update to NA 1.8 engines if desired.

 

Whatever is decided, this has to be the end of parity adjustments for a while. With the exception of slowing down the 1.6, should this be shown to be too much help.

 

I believe this meets the criteria of easy, cheap, won't make it an overdog, easily enforced, does not make the prep shops rich.

 

Todd/Ralph, consider this for the next SMAC meeting.

 

dave

[Bench Racer]

Anyone that posts real test data deserves to be excluded by those that don't post their test data, or don't ya have any test data.

 

Rob, if one checks air fuel ratio at WOT, why would one check temperatures any place less than on track at WOT in 4th gear.

 

James, I'll bow out to your engineering expertize. Get yourself a thermocouple setup and test your car on track at WOT. My 1.6 engine with my ambient air intake of 85* F is 92* F air filter, 85* ambient is 92* F exit AFM, 92 * F exit of AFM is 132* F at throttle body. 8* below your engineering discomfort number of 140* F. If you don't have factual backup data, why enter the post carp, to stir the pot.

 

Ralph/SMA/CRB, my 2 cents worth is many 1.6er's are tired of the site fodder and they keep their pie holes shut. Me on the other hand even tho I as a 73 year old driver can't get there would like to see light at the end of the tunnel. Example, how many left coasters (not far northwest corner guys) that have in the past made comments current or in the past two years have posted that the 1.6 gets pulled off corners or gets pulled do to an on rack situation or they have posted no data from their testing? One great 1.6er example from the left coast that commented on the 99 plus pulling the 1.6 off a corner was team Jordan. Another example of a 1.6 driver that  saw the forest through the tree received his new NB at the June Sprints won his first June Sprints that weekend. If there's 1 or 100 1.6 drivers requesting improved power and the SMAC/CRB is of the belief the 1.6 should have improved power, DO IT with the understanding if the 1.6 becomes an over dog it'll get a plate, or lighten the 99 plus cars.

 

David Dewhurst

[Bench Racer]

 With all the smarts on this site and the engine builders, what is a/your theoretical  power increase percent per each temperature increment of temperature decrease.

 

Those folks that desire a cool air intake, please write a letter requesting wrapping the 1.6 plastic tube be legal.

 

Six hours have passed and no one is manning up to the power increase percent per each temperature increment of temperature decrease.

[Steve Scheifler]

Bench, Google SAE horsepower correction calculations and see if you can find the formula used by dynos.

[dmq]

I race a budget 1.6.

Any inexpensive changes I would make right away, like ducting air from turn signal.  but the more expensive changes would have to wait until next year but would also be welcomed.  People have talked about headers. Any thoughts on cleaning up existing welds on stock headers? Cost nothing.  

 

dave q

[Bench Racer]

Steve, there are so many people in the know on this site yet they seem to get lock jaw rather than be part of a foster situation.

[Jim Drago]

Steve, there are so many people in the know on this site yet they seem to get lock jaw rather than be part of a foster situation.

If referring to me.. I do not have this info or I would offer it. It would be nothing more a guess on my part.. My "guess' is 3-4 hp.. But I don't want to get yelled at about posting non factual tested data

[Caveman-kwebb99]

I own a 99 have raced all models but the 1.6...

I believe it needs nothing. If you want to give it something let them pull the turn signal but then require them to unbend all their headlight covers!

The car is fast but falls off to much late in the race. Question really is... Heat soak? Or it was tuned on a dyno with fans blowing on engine rather then tuned to track conditions? I have no idea.

I see very few 1.6 cars with the SD radiator which runs cooler by 15degree...

If the 15 degree for $600 isn't enough bang for the buck nobody but those that want to have the coty are going to go for it after any big changes are made...

[jdmrrs]

'90 & '99

 

Goal: Make the 1.6's more competitive, but not "the car to have".

 

Solution: Header & turn signal = 3-4 HP & ft-lb & more stable performance (plus offsets loss of heat shield)

 

Jim Morris

[Bench Racer]

If referring to me.. I do not have this info or I would offer it. It would be nothing more a guess on my part.. My "guess' is 3-4 hp.. But I don't want to get yelled at about posting non factual tested data

Not aimed at anyone that doesn't know. I've found 1% (to 1.8% per one source)  power increase per each 10* F increment of temperature decrease. Saul's numbers were similar IIRC. Need to search for his posts on air intake. 

[MPR22]

Anyone that posts real test data deserves to be excluded by those that don't post their test data, or don't ya have any test data.
 
Rob, if one checks air fuel ratio at WOT, why would one check temperatures any place less than on track at WOT in 4th gear.
 
James, I'll bow out to your engineering expertize. Get yourself a thermocouple setup and test your car on track at WOT. My 1.6 engine with my ambient air intake of 85* F is 92* F air filter, 85* ambient is 92* F exit AFM, 92 * F exit of AFM is 132* F at throttle body. 8* below your engineering discomfort number of 140* F. If you don't have factual backup data, why enter the post carp, to stir the pot.
 
Ralph/SMA/CRB, my 2 cents worth is many 1.6er's are tired of the site fodder and they keep their pie holes shut. Me on the other hand even tho I as a 73 year old driver can't get there would like to see light at the end of the tunnel. Example, how many left coasters (not far northwest corner guys) that have in the past made comments current or in the past two years have posted that the 1.6 gets pulled off corners or gets pulled do to an on rack situation or they have posted no data from their testing? One great 1.6er example from the left coast that commented on the 99 plus pulling the 1.6 off a corner was team Jordan. Another example of a 1.6 driver that  saw the forest through the tree received his new NB at the June Sprints won his first June Sprints that weekend. If there's 1 or 100 1.6 drivers requesting improved power and the SMAC/CRB is of the belief the 1.6 should have improved power, DO IT with the understanding if the 1.6 becomes an over dog it'll get a plate, or lighten the 99 plus cars.
 
David Dewhurst

I'll bite.

I assume that since you are posting the temperature at the throttle body you have done some testing. It seems some testing of other cars would give us more data points. 99 intake tubes are not that different from 1.6, so I assume they would they experience the same level of temp increase from the intake tube to the throttle body. There is no reason the under hood temperatures should vary significantly between models. If they do then you are definitely on to something.

[Bench Racer]

Yes, did some thermocouple testing air temperature at air filter, exit AFM and entry to throttle body. Posted numbers in this thread and or the other current 1.6 thread.

 

I presume the intake tube of other engines will heat the air behind the radiator similar to the 1.6 air intake tube. BUT if allowing the 1.6 and all other engines to wrap the air intake to were made legal, no advantage for the 1.6 which needs a bone.

 

It's my guess that a letter or so have been written requesting the parking light removal for ambient air intake. Because of the air temperature increase through the tube between the AFM and throttle body I've written a letter requesting the 1.6 be allowed to wrap the tube. My ambient air intake pictures are posted under Tom Hampton's name. See post #73 by Todd Green for ambient air intake picture address.

 

[Steve Scheifler]

Someone told me the 1.6 tube is lower and gets more air through the radiator across it than NBs. I have not confirmed that. I do agree that +40 seems like too much from just the tube. How many CFM is moving through there at 5500-7200 rpm? I would think the intake air velocity is high enough that it is in the tube a fraction of a second.

[James York]

 

 

James, I'll bow out to your engineering expertize. Get yourself a thermocouple setup and test your car on track at WOT. My 1.6 engine with my ambient air intake of 85* F is 92* F air filter, 85* ambient is 92* F exit AFM, 92 * F exit of AFM is 132* F at throttle body. 8* below your engineering discomfort number of 140* F. If you don't have factual backup data, why enter the post carp, to stir the pot.

 

 

David Dewhurst

 

Ok.  Perhaps I wasn't clear or you misunderstood the 140 comfort temp.  In order for heat to transfer from the tube to the air, it must be much hotter than the air you "measured".  For example, the tube might need to be 180 F to permit the required heat to transfer in the short of time the air is in actually contact with the tube.  Perhaps your thermocouple is not just measuring air temp, but it is touching metal, which is much better heat transfer material?

 

Just take this example.  I used 170 CFM air (I think this is close to the rated flow of the AFM for a 1.6), at 80F inlet.  Using an assumption of 5 foot long tube (longer will give more heat transfer area), 5 inch ID (larger will give more heat time due to slower flow), and a heat transfer coefficient of about 6 (W/m2 K; typical of forced air over convective air), 300F in the engine bay will raise the temperature 8F.  To raise the temperature 40F, the engine air side would need to be over 1000F (I quit checking at that point)

 

Note, at a flow rate of 170 CFM, the air takes roughly .25 seconds to go down the tube.

 

Ignore or not.  It doesn't matter to me.

[Bench Racer]

Like wise ignore that my thermocouple was not touching metal and the thermocouple read a 40* F temperature increase. Two other received pm's indicated they measured the similar 40* temperature increase between AFM and throttle body. My racing season is over, my letter with request to wrap tube is sent and the results of the letter will be the results. 

[cam]

Bench:

 

Are you running an aftermarket radiator?  Is the upper radiator hose in contact with the air tube?  Some of the aftermarket radiators have the upper hose connection in such a way that the hose either physically touches the air tube or is at least very close to the air tube.  Is there a way to check if that is the primary contributor to the extra heat you found in at the throttle body? 

 

On my 1.6, I always made an effort to keep the air tube as far away from the upper radiator hose as I could. But it was always a very close fit.

 

I have to agree with James that the heat transfer does not make sense.  I'm not refuting your empirical evidence, hence my question about the radiator hose, looking for an alternative source of heat.  Would be interesting to hear if you have any other theories.