How bad is turbo without intercooler?

[jamesm]

my mazdaspeed mx-5 came with a comically small intercooler that would actually heat soak on the dyno and become an 'interheater'.

here's an example of an aftermarket kit for a high compression car (cayman/s) that has no intercooler. they're also only running 4psi.
http://www.tpcracing.com/tpcracing-987-stg1-turbo.html

everyone here is correct in that 'can i do it' and 'should i do it' are two very different answers. there are a lot better ways to save money when piecing together a kit. even an ebay core would be better than nothing. but, it can work if necessary at low boost.

[mid_life_crisis]

Originally Posted by nonicname

Toyota uses non intercooled turbo engines outside the US. I couldn't believe it when I saw it. I actually believe it was a diesel engine though so I'm not sure if that makes a big difference.

Diesel engine is essentially controlled pre-ignition, if that makes any sense at all to you, so it wouldn't surprise me in the least.

[Drift-Office]

Originally Posted by ft_sjo

It's bad. Like crossing the streams.

I got that reference!

While I was @ 86EXPO this last weekend, this was exhibited by fellow member @ 86ZN6 - presumably the WORKS non-intercooled turbo kit that's currently under development...

FYI...

[AVOturboworld]

4~5psi on a 9:1 motor vs. a 10:1 motor vs. a 12.5:1 motor is going to yield vastly different results, with many other modifiers such as the size of the stock oiling system, radiator size, engine size, and a host of other factors.

If you lived in a year-long cool climate, and had access to 93 octane gas or better, you may be able to get away without intercooling on this particular motor. But never go near a circuit, don't do extended driving at high rpms, and make sure you never run 91 octane gas.

Personally, the trade-off isn't worth it. In exchange for 4 hours of your life installing a FMIC along with the $1000~1500 for the parts, you can go from having to be always careful with it to just being able to drive without worrying if you'll have a $5~6k engine replacement bill in the near future.

And definitely go nowhere near Nevada without that intercooler - the combination of 91 octane and 110+ degree heat is going to be deadly unless you are very light footed. OTOH, we were giving test drives to 85 Expo members without issue in 115 degree heat at higher boost levels.

[mid_life_crisis]

Originally Posted by jamesm

my mazdaspeed mx-5 came with a comically small intercooler that would actually heat soak on the dyno and become an 'interheater'.

It didn't help matters that it was mounted inside the engine compartment.

everyone here is correct in that 'can i do it' and 'should i do it' are two very different answers. there are a lot better ways to save money when piecing together a kit. even an ebay core would be better than nothing. but, it can work if necessary at low boost.

I guess my real point here is: if your goals are modest and it isn't necessary, can you save the bucks for something else and not have to tear apart your front end? Less money, less trouble installing, if everything works and meets the goals reliably without it, why do it?
Star Trek fans will recognize this line: "the more they fancy up the plumbing, the easier it is to stop up the drain." Keep it simple. That article in the second post was an eye opener.

[ft_sjo]

Originally Posted by Drift-Office

this was exhibited by fellow member...

Hilarilous......

[Whitigir]

Originally Posted by mid_life_crisis

Diesel engine is essentially controlled pre-ignition, if that makes any sense at all to you, so it wouldn't surprise me in the least.

This is Correct

Diesel doesn't have Spark Ignitions. Diesel ignite itself on designed Compression, and heat created from compression.

The compressed Diesel + Air Mixture will be Exploded instead of Fired and burn like Gasoline engine. That is why Diesel engine are Heavier and have more Torques due to high Compression.

It is possible to engineer a Turbo Diesel without Inter cooling

[nonicname]

Originally Posted by AVOturboworld

4~5psi on a 9:1 motor vs. a 10:1 motor vs. a 12.5:1 motor is going to yield vastly different results, with many other modifiers such as the size of the stock oiling system, radiator size, engine size, and a host of other factors.

If you lived in a year-long cool climate, and had access to 93 octane gas or better, you may be able to get away without intercooling on this particular motor. But never go near a circuit, don't do extended driving at high rpms, and make sure you never run 91 octane gas.

Personally, the trade-off isn't worth it. In exchange for 4 hours of your life installing a FMIC along with the $1000~1500 for the parts, you can go from having to be always careful with it to just being able to drive without worrying if you'll have a $5~6k engine replacement bill in the near future.

And definitely go nowhere near Nevada without that intercooler - the combination of 91 octane and 110+ degree heat is going to be deadly unless you are very light footed. OTOH, we were giving test drives to 85 Expo members without issue in 115 degree heat at higher boost levels.

case closed! i believe this guy!

[qoncept]

Originally Posted by AVOturboworld

4~5psi on a 9:1 motor vs. a 10:1 motor vs. a 12.5:1 motor is going to yield vastly different results, with many other modifiers such as the size of the stock oiling system, radiator size, engine size, and a host of other factors.

If you lived in a year-long cool climate, and had access to 93 octane gas or better, you may be able to get away without intercooling on this particular motor. But never go near a circuit, don't do extended driving at high rpms, and make sure you never run 91 octane gas.

Personally, the trade-off isn't worth it. In exchange for 4 hours of your life installing a FMIC along with the $1000~1500 for the parts, you can go from having to be always careful with it to just being able to drive without worrying if you'll have a $5~6k engine replacement bill in the near future.

And definitely go nowhere near Nevada without that intercooler - the combination of 91 octane and 110+ degree heat is going to be deadly unless you are very light footed. OTOH, we were giving test drives to 85 Expo members without issue in 115 degree heat at higher boost levels.

I wouldn't bother with the modest gains you'd see on a non-intercooled turbo on a 12.5:1 compression engine, but ...

What you're saying above just doesn't make any sense to me.

- The radiator has nothing to do with intake air temp. Same with water and oil temps and capacities. The only thing you could be thinking that makes any sense is the temperature under the hood increasing intake air temp, which is going to be practically zero compared to the increase due to compression. Yes, you'll want a bigger radiator or oil cooler because these engines already run hot and will get hotter with higher output, but that has nothing to do with an intercooler.

- Wherever you are, and whatever gas you use, you're going to tune your car. If you're in superhot Nevada you'll have appropriate levels of fuel and timing advance. Octane levels aren't some magical threshold, it's a scale and the levels tuned for (including from the factory) are what is available. You tune the car so it doesn't knock, period. Tune your car (well) for 91 and it will be fine on 91.

- How long you're able to stay in boost is ... well, it makes no sense at all to me. You're tuned to deal with the heat. If anything, how long you're on it matters LESS because you'll never have a heatsoaked intercooler.

[SkAsphalt]

Originally Posted by Whitigir

How bad ? Very Bad.

1/ Turbo Works by using the Wasted Exhaust Hot Air to spin the Wheel, which is connected to the Turbine by the Shaft, which then turn the Turbine wheel, which will suck air in for you.

2/ Compressed air, or anything compressed will be Heated up, together with the Hot Air from the other side which heat it up faster = Recipe for Pre-ignition or Knocks....

3/ Your engine goes BOOM! in time

Sorry but you're spreading fear more than information. Yes inter coolers are key but there are turbo applications without inter coolers installed. They just do not produce tuns of power.

You could pull the intercooler out of the first celica-supra turbos and route things differently and barely notice as long as you didn't track the thing. the intercooler was the size of a 1 litre coke bottle.

[mad_sb]

Originally Posted by Drift-Office

I got that reference!

While I was @ 86EXPO this last weekend, this was exhibited by fellow member @ 86ZN6 - presumably the WORKS non-intercooled turbo kit that's currently under development...

FYI...

1. EWWWWWW
2. They put the passive cooler on the intake side?

[s2d4]

Originally Posted by mad_sb

1. EWWWWWW
2. They put the passive cooler on the intake side?

Not sure if you can call that a cooler...

[qoncept]

Originally Posted by mad_sb

1. EWWWWWW
2. They put the passive cooler on the intake side?

Lol, I didn't notice that. So now, instead of your intake being ambient temp at the turbo, it's very slightly heatsoaked. And, of course, nothing cools it after that. Genius.

[AVOturboworld]

Originally Posted by qoncept

- The radiator has nothing to do with intake air temp. Same with water and oil temps and capacities. The only thing you could be thinking that makes any sense is the temperature under the hood increasing intake air temp, which is going to be practically zero compared to the increase due to compression. Yes, you'll want a bigger radiator or oil cooler because these engines already run hot and will get hotter with higher output, but that has nothing to do with an intercooler.

If the engine is already running hot in n/a form, especially at the track, then adding power is only going to increase that heat. The heat is, in the main, generated in the combustion chamber - and your oil and water cooling system is there to lower that temperature as much as possible. Running without an intercooler will raise those combustion chamber temperatures even higher. Knock and detonation will increase exponentially.

What I'm saying is that the situation is complex. If your engine was already at the limits of the standard cooling system, adding boost without cooling the charge temperature will tax it beyond the cooling capacity of the system. What's the point of adding a FI system if you could only run 1psi of boost?

- Wherever you are, and whatever gas you use, you're going to tune your car. If you're in superhot Nevada you'll have appropriate levels of fuel and timing advance. Octane levels aren't some magical threshold, it's a scale and the levels tuned for (including from the factory) are what is available. You tune the car so it doesn't knock, period. Tune your car (well) for 91 and it will be fine on 91.

Seriously? You make it sound like you could tune the car to run boost on 87 octane, and the stock motor isn't even barely capable of that. That's because you can only do so much ignition retard before your EGT's get too high and start melting other components. So, yes, octane levels *are* some magical threshold.

The other problem in that statement is that it ignores what happens when you drive cross-country.

- How long you're able to stay in boost is ... well, it makes no sense at all to me. You're tuned to deal with the heat. If anything, how long you're on it matters LESS because you'll never have a heatsoaked intercooler.

Motors overhead in racing because the longer you stay at extended rpm's, the more heat in the engine that the cooling system has to deal with. 95% of street (OEM) systems are designed for occasional high-rpm usage, and can (and usually do) start failing when used constantly at high rpm's.

Adding boost - hot, compressed air - is doing similar things as running at higher rpm's. All FI systems are equal in this regard. Intercoolers are there to help alleviate that fact. Given that the discussion is about non-intercooled FI, it's even more relevant on how long you remain in boost. Intercoolers are not the only component in the engine that become heat soaked.