TurboTim

http://www.speedforceracing.com/dyno...oolerdyno1.jpg


Here is a before and after dyno chart with one of our intercoolers.As you can see there were big gains on a car that wasnt even making 300 horsepower at the wheels.We will be dynoing one of our test cars that makes about 390 at the wheels with our intercooler very soon.Hopefully this will be enough to convince everyone out there that an intercooler upgrade is a worthwhile investment.

Another point of interest.We have a seen as much as a 4 psi pressure drop through the stock intercooler! This means that you guys that are seeing 20 psi on your boost gauge are actually running close to 24psi out of your turbo! This could lead to decreased performance if you are out of the efficiency range of your turbo.

RobNL

I'm a little now. I thought that the boost pressure was measured between the turbo and the IC, so it should measure the pressure created by the turbo. How does the IC affects these measurements?

Furthermore on the dynochart, the difference is quite large between 4000 and 4600 rpm, but at 5000 rpm the difference is almost negligible. Does this means that there are other parts being more restrictive than the IC, such as the head or intake manifold, or is it just the turbo that can't keep up anymore?

I do believe that high HP cars needs an improved IC, but when does the IC becomes the weakest link in the chain. Should other parts, such as the head be upgraded first, to utilize the full potential of an improved IC.

TurboTim

Boost pressure is measured inside the intake manifold. To find out the pressure drop:

pressure before intercooler-pressure after intercooler=pressure drop

This dyno data that I provided is by no means enough to end the great debate of whether a person should upgrade their intercooler before doing other mods. It is just some evidence to support the fact that even a car that makes under 300 horsepower at the wheels is a good candidate for an intercooler upgrade.

My personal opinion is that the intercooler should be one of last mods done to the car because of the bang for the buck factor. Once you have done all the basic bolt-ons, then it is time for an intercooler upgrade.

Bengt Sweden

If you have an IC that is efficient in cooling you should see this in pressure drop!
When measuring gases you must always consider both temperature and pressure. Some of the pressure drop is from flow restrictions and some from temperature drop. The lower pressure you get from the temperature drop helps to drive flow which is what you want.

Bengt

Bengt Sweden

BTW I have done some dyno testing on water injection at the university. The objective was to replace the over rich WOT condition to reduce emissions, not to improve performance but anyhow, hp decreased. This is due to slower combustion which partly can be compensated by advanced timing.
To use water injection for cooling the charge, to increase air density, do not work. If you want efficient cooling you need to get phase transition (evaporation), but the water vapour takes up much more space than you contract the air so in total you get less air into the engine. If you need water for knock control it should be injected in liquid phase into the combustion chamber.

Water spraying on the IC on the other hand sounds very interesting. This type of heat exchange system is widely used in industry applications and should have high efficiency. I have an old fire extinguisher with CO2 laying around so I might do a dyno run with that one as well to test the difference.

Bengt

fast951

Bengt,

Wouldn't mixing alcohol or methanol with the water help?
Water by itself may not be as effective.

I plan on doing some testing on the 951.. Will share the findings when complete.

Bengt Sweden

Fast 951
Sorry but any liquid evapourating will steal space from the air. The same goes for fuel. You want the fuel emulsified not evapourated or you get the same problem. That is one of ther reasons to have the injectors close to the inlet valves.

The alcohol can of course help as an octane booster.

B

TurboTim

I agree with you 100%. The more the air cools, the more of a pressure drop you will see. I also think that the 944 turbo intercooler does a pretty good job of cooling the charge air. However, I have been able to do some back to back testing with our intercooler on a few occasions and I can say that you pick up one to two psi of boost just by installing it. It also cools the charge air even better then the stock unit, especially after repeated full boost runs on the dyno or at the track. Now...... I am not getting all scientific with my testing;^) I am using a simple boost gauge and taking readings off of the MAT sensor in my datalog files. I have seen enough to convince me, though. Take care.

Danno

"If you have an IC that is efficient in cooling you should see this in pressure drop! "

Pressure would drop for the same CFM flow due to the cooler air and higher density exiting the intercooler. But if you have a sophisticated boost-control system, it would compensate to generate the same outlet pressure by spinning the turbo more to cram more air through the inlet. So 15psi with stock intercooler yields a certain xyz CFM flowing into the engine. With a better intercooler and appropriate boost-controller, that same 15psi ends up flowing maybe xyz+10% CFM.

"To use water injection for cooling the charge, to increase air density, do not work. "

It depends upon how it's implemented. The benefit of water-injection is to drop the air-temperatures an additional 50-60 degreesF. General rule-of-thumb is every 10-F yields a 1% increase in power. This increase in power is not from additional air-density as much as knock-reduction allowing you to advance the timing and running more boost.

"Sorry but any liquid evapourating will steal space from the air. The same goes for fuel. You want the fuel emulsified not evapourated or you get the same problem. That is one of ther reasons to have the injectors close to the inlet valves. "

What do you mean emulsified? As small droplets? Since water and fuel are much of higher molecular weight than air, they occupy a much smaller volume as a gas than an equivalent mass of air. So in a stoich 14.7:1 of air-fuel mixture, the fuel actually occupies much less than 1/14.7th of the volume. Plus it fuel doesn't displace air as its injected, it's not like air is being pushed out backwards from the engine when fuel is injected, but the overall pressure of the mixture may be increased slightly with the exact same amount of air flowing into the engine with or without fuel injected. Studies have found significant power increases to be had by moving the injectors farther away from the intake valves to have more air-volume between them to evaporate the fuel better. Also high-pressure fuel-systems of 100psi+ with specialized injectors to instantly mist the fuel on injection provides significant power gains as well.

Chris Prack

I can say that a guy that I work with installed a water injection kit on a 930 with a K27. It made a small gain in hp. The big deal was the torque gain that it made, in the neighborhood of 30 ft/lbs. with just distilled water.

Bengt Sweden

Danno

I did not say that the pressure drop was something negative. Actually without a pressure difference you will have no flow at all!
The increased pressure difference due to cooling will drive flow. A boost controller will, as you say, increase flow even further until set pressure is reached. This can be problem as well as a benefit. On a cool day you will charge much more (air mass) and perhaps reach levels where you get knocking. So I guess what we really want is a boost controller that controls mass flow as well.

I did say that you could use water for knock control, but it will not increase power by itself and advancing ignition will not bring back all that you loose from slower combustion. Increased boost, when possible, will of course add hp.

The slower combustion is not due to temperature difference but chemically from the water interfering in the combustion process. This will give lower top pressure and less risk of knocking.

Yes the negative effect of evapourating the fuel is much less than evapourating the water but the principle still applies. If you add a gas in the manifold, it's partial pressure will be added to the total pressure and steal space which could be used for air in stead. Of course it wont flow backwards, it will just prevent this air from entering the manifold.

I have not seen any reports showing benefits from moving the injectors away from the inlet valve and I have not seen any modern car that do not inject as close to the inlet valve as possible. Please tell me where you have seen this.

High pressure injection is as you say to get a mist (small droplets), not a vapour.

cheers Bengt

hrk

I installed simple on/off water injection to my -86 Turbo.
It fires at 11 psi of boost while my max boost is 14 psi. I am using water methanol mixture.

On street when you are on boost very short amounts of time it works fine.

On track where water is sprayed pretty much all the time I had problems with soaked TPS. My worn throttle body leaks air which is ok but water is harmful to electronics on track when 80-90% time car is on max boost.

I am looking into rebuilding mine or making barrel type throttle body with radial seals which could be bolted on stock manifold.


I haven't dynoed mine with or without water injection, but the difference with water on and off is not dramatic by any means, on Road Atlanta backstraight maybe couple of mph, which can also be better launch from earlier corner. I am using the smaller of nozzles provided with kit and will test more once TPS problem is overcome.

It would make much bigger difference if the boost were maximized with water.

I was looking for extra safety when using higher than stock boost.

hrk

crazyracer

Here is a dyno chart for a Saab 900 turbo with and without water injection installed. No gain at all.

http://www.lehigh.edu/~erp4/Dyno.html