Ct26 Turbo

[disco]

hi,

does any one know whats the maximum psi i can run on a standard ct26 with out affecting reilabilty to much ive only just fitted my new turbo.

cheers

dave

[Bibbs]

17psi is about the limit .. and you'll need all the other cooloing mods to go with it .. WI, IC, etc ..

[Jesus]

I'm running about 16psi. Like Bibbs said, you really need to sort the cooling to prevent detonation when upping the boost. Too many people get power hungry and turn up the boost for more power without investing in the cooling side.

For information... in outside temperature of approximately 23oC the temperature at the intake is about 25oC (all figures for when car is up to 'operating' temperature, using the stock intercooler, running ~16psi boost, on my car). Temperature of the charge after just going through the turbo with no boost gets to approximately 50-60oC just before going into the intercooler. When it comes out of the intercooler, the temperature is back down to approximately 28oC. This is efficient cooling... but only off boost.

When on full boost, the temperature of charge just as it's going into the intercooler gets up to 120oC. Almost unbelievable. It comes out of the intercooler at about 60oC+. Although it's cooling the charge to half, it is still above an ideal charge temperature of ~35-40oC. Even at 16psi boost, if you haven't implemented better cooling, such as bigger core intercooler, or better still chargecooler, you're running a bigger risk of detonation. You can use water injection, but really only as a last resort to getting core temperatures down in the chambers.

Toyota specced the cooling system to operate for stock boost. Whatever you do when tuning an engine, it has a knock-on effect somewhere down the line.

[Bibbs]

Jesus .. ever thought about testing WI ?

[Jesus]

Depends where you're throwing the water into the mix. Are you putting your water/methanol mix into the throttle body?

If so, I could my own up like yours (including lovely 3 litre bottle of moonshine in the boot!), measure the charge temperature straight out of the intercooler, and then again at the inlet manifold prior to being dumped into the chambers. Then make a comparison. I wouldn't mind knowing myself... as I'm sure others would. Leave it with me to think on. <_<

[Bibbs]

Mine is just after the IC .. you can add another before too .. if you are serious ..

and can't beat the old moonshine :)

[Jesus]

I'm getting a chargecooler fabricated at the minute, so will have some more results then... here's an idea... re-route the air-con system to a sealed air box around the stock intercooler! ;)

[mattmr2]

Weve had some very good results from our charge cooler kit, the prototype was fitted to a car with all kinds of temperature probes.... they guy was originally running a spearco intercooler and was seeing charge temperatures of around 76 deg on full boost, they are now down to around 40 deg which means you can boost to hell and back if you like!!!....If memory serves me correct the top of the range IC's for the 2 are about 76% efficient, our chargecooler works out around 84%, which is nice! A charge cooler is deffo the way to go if your looking to run serious power saftly - good choice Jesus, let me know how you get on with it....

Matt.

[EarL]

Weve had some very good results from our charge cooler kit, the prototype was fitted to a car with all kinds of temperature probes.... they guy was originally running a spearco intercooler and was seeing charge temperatures of around 76 deg on full boost, they are now down to around 40 deg which means you can boost to hell and back if you like!!!....If memory serves me correct the top of the range IC's for the 2 are about 76% efficient, our chargecooler works out around 84%, which is nice! A charge cooler is deffo the way to go if your looking to run serious power saftly - good choice Jesus, let me know how you get on with it....

Matt.

Matt,

What's the difference between an intercooler and a charge cooler? S'cuse my ignorance

[Jesus]

Don't mean to answer for Matt, but basically an intercooler 'cools' the charge temperature (inducted air) using air. A chargecooler 'cools' the charge temperature (inducted air) using water. After the inducted air goes through the turbo, the temperatures soar well above the optimum heat and therefore needs cooling... so before the air goes into the inlet manifold and chambers it goes through an intercooler, which is basically a radiator for air. A better way of cooling the air is with a chargecooler, which replaces the intercooler.

A charge cooler is a lot more efficient at cooling the air as it uses a cold water supply. The water supply in itself must also be cooled to increase efficiency. The chargecooler is most simply described as an intercooler with the 'fins' boxed in and supplied with water running over and through them instead of air. A chargecooler does not rely on a cold air stream like the intercooler, and can therefore be mounted where practical. As we all know, we don't have the benefit of a large cold air supply coming straight into the front of the engine bay on an MR2... it has to come in through the air ducts on the side, which in themselves are not very efficient when it comes to volume of air per minute. Subsequently, the lower you can keep your charge temperatures, the higher boost you can run and more power you can put out without the risk of detonation... put simply. :)

[daktari]

Has anyone tried nitrous cooling the intercooler. I`ve seen pics of it working but dont know how effective it is or how costly to run. I`ve heard excellent reports of the aquamist system as well. Any comments? :D

[Jesus]

My understanding is that the Aquamist systems essentially put water spray into the airflow to cool the charge temps down as opposed to cooling the intercooler down. Similar to Bibbs' water/methanol setup.

Nitrous is good for cooling, as is CO2 (Carbon Dioxide) when sprayed onto the intercooler. This, however, can work out very costly and to be efficient needs to be mapped into the parameters of the ECU. Normally triggered off a combination of boost, charge temp, throttle position and driving style. You can't really have it on permanently, it needs management. CO2 also needs to stay well away from the induction system as you don't want it putting out your internal fires!!!

The 'all toys' scooby's and evo's come with intercooler water spray (IC Water Spray) which is essentially what I've said above, but using water instead... a lot cheaper, but not quite as 'chilling'.

The way to go is chargecooler... and if running extremely high boost in a highly modified engine... run a little water injection too to stay on the safe side of detonation.

[EarL]

Don't mean to answer for Matt, but basically an intercooler 'cools' the charge temperature (inducted air) using air. A chargecooler 'cools' the charge temperature (inducted air) using water. After the inducted air goes through the turbo, the temperatures soar well above the optimum heat and therefore needs cooling... so before the air goes into the inlet manifold and chambers it goes through an intercooler, which is basically a radiator for air. A better way of cooling the air is with a chargecooler, which replaces the intercooler.

A charge cooler is a lot more efficient at cooling the air as it uses a cold water supply. The water supply in itself must also be cooled to increase efficiency. The chargecooler is most simply described as an intercooler with the 'fins' boxed in and supplied with water running over and through them instead of air. A chargecooler does not rely on a cold air stream like the intercooler, and can therefore be mounted where practical. As we all know, we don't have the benefit of a large cold air supply coming straight into the front of the engine bay on an MR2... it has to come in through the air ducts on the side, which in themselves are not very efficient when it comes to volume of air per minute. Subsequently, the lower you can keep your charge temperatures, the higher boost you can run and more power you can put out without the risk of detonation... put simply. :)

Thanks Jesus.

[Spartan]

Surprised it isn't more common for the MR2's. Probably because chargecoolers don't get a look-in with other turbo applications.

A nice simple explanation of chargecoolers is that they are pretty much the same as your engine coolant system except they cool air from the turbo.

They have a header tank, water pump and a radiator (pre-rad) to cool the warm air after it has gone through the chargecooler.

[Bibbs]

The charge cooler off a GT4 will work .. a CC is just an IC in cold water.

The problem is cost .. an IC is cheap in manufacture compared to a CC.

The only reason the GT4 got a CC is cause it needed one to be able to use them on the rally cars ..

[mattmr2]

Matt,

What's the difference between an intercooler and a charge cooler? S'cuse my ignorance

Basically an intercooler 'cools' the charge temperature (inducted air) using air. A chargecooler 'cools' the charge temperature (inducted air) using water. After the inducted air goes through the turbo, the temperatures soar well above the optimum heat and therefore needs cooling... so before the air goes into the inlet manifold and chambers it goes through an intercooler, which is basically a radiator for air. A better way of cooling the air is with a chargecooler, which replaces the intercooler.

Wow thats the quickest I ever typed!!!

Matt :D