BOOSTED guys help me out.

[zukitek]

I have been doing some poking around and really have not come out with anything definitive on the subject of intake air temp limits on boosted motors . I am a little nervous about the IATs I am seeing on my 240.

Cruising out of boost with an engine compartment temp of around 190* my IATs are between 140-160* but if I do a good hard pull starting in 2nd gear to teh shift light at 5500 RPMs and do this through 4th gear my IATs climb to 250* and spark retard begins progressively at 180*(pulling 1* of timing ) then at 200* it pulls 2* then at 220* it pulls 4* and pulls 2 more degrees for every 20 degree increase after that. This is bothering me because I really dont wanna melt something and I really dont have a clue as to how high the IATs would climb on a 15 minute track day session but I am guessing they would go through the roof but I am not ballsy enough to take it to the limit to see where the IATs level off .

Is there some sort of rule of thumb when it comes to boost and IATs and at what point does one say that is far enough. My only avenue to do anything to lower the IATs is water/methanol injection or reconfigure the intire intake and supercharger system to incorporate an intercooler. Suggestions are welcome .

[TouringBubble]

My IAT sensor is in the MAF, so I don't have records of temps at the intake. What kind of AFRs are you running?

[zukitek]

My IAT sensor is in the MAF, so I don't have records of temps at the intake. What kind of AFRs are you running?

Under boost the AFRs are from 11-12.5. I can only assum this is going to skyrocket the EGTs as well. It does not take much of an increase in EGTs to overheat that wideband sensor . At TGPR the wideband set a sensor overheat code just before the engine let go but at that time I was not monitoring IATs at the intake after the charger as I am now .

Ignorance is bliss. Before the rebuild I was only monitoring IATs ahead of the throttle body and had no idea the IATs after the charger were that high but as I said ...I really dont know how high is too high but I for darn sure dont think 225-250 is good because the IAT guage on tuner studio turns red ...that cant be good !!!!!

[fwman1]

I've had my supercharger on for a couple of years, but have not tried to max out the boost. I've looked into it, and have tried to learn about different methods to deal with increasing IATs. I'm guessing that you would want to go water/meth injection. I don't know if your setup works like a miata, but the addition of any decent size intercooler causes idle droop issues like crazy unless you use a dual throttle body setup. I'd like to look at your setup at the Sunday TnT if you'll be there.

[EWaugh]

I had a conversation about this with Jim at Motorvations about this and Ian's car. The way he put it you'll hear the motor start making noise long before you do any damage. As long as you back it off and let it cool you won't hurt anything. Is he right? I don't really care to find out.

[zukitek]

I had a conversation about this with Jim at Motorvations about this and Ian's car. The way he put it you'll hear the motor start making noise long before you do any damage. As long as you back it off and let it cool you won't hurt anything. Is he right? I don't really care to find out.

Evan, I dont know in what context Jim was speaking when he said you would hear the noise long before damage but ...I can tell you from experience ...this is not the case with a motor that has cast pistons like mine did . You might hear the detonation and you may not but if detonation occurs ...there is very little time for backing off before damage occurs .The ring lands will fail and you just see the smoke and smell the oil as the ring lands fail and the boost begins to huff all of the oil from inside the engine to the outside of the engine through whatever orifice it can find ...usually the valve cover breather into the intake tube.

It happens that fast ..REALLY!

[zukitek]

I'd like to look at your setup at the Sunday TnT if you'll be there.

Matt , my son, is starting UAB in the fall and is going into mechanical engineering so Sunday there is an open house that my wife and I are attending so if I make it I can only stay till 10 or 11 AM

[fwman1]

Ricky, you may want to look at a TurboXS Knocklite.

http://www.jdmpartswholesale.com/product/turboxs-universal-knocklite-knock-detection-shift-light

[TouringBubble]

On E85 at WOT, aim for an AFR (gasoline scaled) of no leaner than 12.2:1 ... maybe even drop to 11.8:1 at redline. This will mainly help your EGTs and not your IATs, but will also promote fuel stability in the cylinder. So, less chance of knock overall, no matter the IATs.

You said you were running NGK 7 range plugs, right? Non protruded? Just going over things you CAN control.

With your setup, the only think I can think is to build a dedicated feed for the intake and perhaps a box to shield out the hot engine bay air. Not much you can do to cool the charger or the charge air with that setup. Maybe feed air to the intake and around the charger?

Also, are you actually getting knock, or is MS just pulling timing based on the AIT reading? As stated, I don't have a way to monitor my temps post-TB, but the 200º+ temps do sound high to me ... thats oil temp range. If you aren't actually getting knock, however, you could modify the IAT protection values in MS and get rid of the timing pull. But, you'd definitely want to monitor for knock in that case.

[zukitek]

On E85 at WOT, aim for an AFR (gasoline scaled) of no leaner than 12.2:1 ... maybe even drop to 11.8:1 at redline. This will mainly help your EGTs and not your IATs, but will also promote fuel stability in the cylinder. So, less chance of knock overall, no matter the IATs.

You said you were running NGK 7 range plugs, right? Non protruded? Just going over things you CAN control.

With your setup, the only think I can think is to build a dedicated feed for the intake and perhaps a box to shield out the hot engine bay air. Not much you can do to cool the charger or the charge air with that setup. Maybe feed air to the intake and around the charger?

Also, are you actually getting knock, or is MS just pulling timing based on the AIT reading? As stated, I don't have a way to monitor my temps post-TB, but the 200º+ temps do sound high to me ... thats oil temp range. If you aren't actually getting knock, however, you could modify the IAT protection values in MS and get rid of the timing pull. But, you'd definitely want to monitor for knock in that case.

IATs are the only reason its pulling timing at this time . I do have a turbo XS knocklite hooked up and functioning and i do get a moderate knock indication sometimes on the up shift when initially jabbing the throttle but on a WOT pull in 4th or any other gear I dont get it so I am thinking that is the initial lean out on acceleration enrichment . I have tried to tune that momentary lean spike but I have not had a ton of luck without making it real rich once it recovers from the initial throttle opening . I am still gathering the components to condition the knocklite signal to be seen by the MS. The duration of the signal is too fast so I have to build a circuit in the proto area to slow that down .

As you can see from the pics I posted in my rebuild thread, the air intake can be better and will be insulated from the engine bay better to try and get the beginning IATs lower but as you said , not much outside of introducing some fuel ahead of the charger or water/meth injection will do much for post charger IATs.

[Cholewa]

The volvo goes cold IAT (read at the manifold) before boost at around 110-120, and jumps up to 150 off throttle after WOT in full boost. My intercooler doesn't really cool well and needs to be cleaned out (god knows how much oil is lodged in there). This was back when I had the failing 42/48 at 15.5 psi. I'm assuming those temps are in F not C but that's just what my MAT sensor reads out in megalogviewer.

By the end of the dyno time, It was staying hot longer, but that was really the only issue I ran into, coolant temps were fine, oil was fine, power was fine, I just heatsoaked the hell out of the intercooler.

AFR's at full boost settling in were mid to high 11's on 93 at around 75% duty cycle.

My biggest concern isn't the initial lean when I blip the throttle, but the lean out immediately AFTER WOT, where the throttle plate closes and it jumps to 18 and then settles back down.. I would feel much better if it stayed in the 12's or 13's after WOT assuming that it was still injecting some fuel to help cool the cylinders a bit.

[Cholewa]

Oh, and as far as suggestions: get an intercooler.

[jledford]

That seems really high for IAT's just cruising around, do you have a front mount IC?

On my old Laser and Evo (both had AEM EMS) I would barely be above ambient IAT's at the throttle body (post IC) when cruising. I could do a 1/4 mi drag pull and have a 20-30 deg temp change over the entire run and my high EGT on a 80 deg ambient day might be 110 deg at the end of the 1/4 mile. This was with the NICE Greddy 4" IC core that all of the DSM crowd likes.

[Cholewa]

That seems really high for IAT's just cruising around, do you have a front mount IC?

On my old Laser and Evo (both had AEM EMS) I would barely be above ambient IAT's at the throttle body (post IC) when cruising. I could do a 1/4 mi drag pull and have a 20-30 deg temp change over the entire run and my high EGT on a 80 deg ambient day might be 110 deg at the end of the 1/4 mile. This was with the NICE Greddy 4" IC core that all of the DSM crowd likes.

He's running a supercharger.

[zukitek]

He's running a supercharger.

there in lies the problem . I have weighed the options and for the effort it would take to intercool this thing I might as well turbo it .