How To Lower Intake Temps Without Alky

B

Boost231

What's An Intercooler
Staff member
Joined
May 26, 2001
So since Jerryl likes to make me think of things lets talk about, How to lower intake charge temps.


How can we lower our intake charge temps without alky?

Does changing to a bigger turbo lower charge temps?

How much does ambient temps effect our charge temps?

How does boost pressure effect temps?

Does alum head vs irons help?

Does the size of the throttle body effect temps since the setup is a draw through?

Basically how do we lower our intake temps?

Would
 
I see a can of worms about to open up Brent. All the HA intakes (C/T or SFI) are restricted quite a bit to help the torque curve. By doing this the surface area of the intake is increased so you've got more contact of the air to the metal of the intake. This creates heat through friction of air movement as well as surface contact. You also develope heat when the air's compressed by the turbo. Going with a turbo that flows more is one way to decrease heating by volume at a lower pressure and if you can decrease the internal area of the intake passeges on an SFI intake, or increasing the internal volume of a C/T intake then you'll get a better air charge.;)
 
how about modifying the factory exhaust heat riser to seal if from the exhaust ports so that cold c02 could be sprayed thru it?
 
Can of worms. Sweet, cant wait to see some input on this topic
 
Ok Boost231 . . .You know you LOVE talking about this and do not need provoking . . . :p

Ok . . . lets talk in general layman terms so I can understand it . . . . We are mainly talking about temps . . . You will see why below.
Oh . . . . this is “off the cuff” . . . . so bear with me . . .

We know mass flow creates HP. Mass flow is rated in “lb/hr” so “mass of air over time”

Let’s brainstorm the variables affecting mass;
Total mass of the air is a function of specific gravity, temp & volume.
Cooler temps, lower elevation = higher mass.
Let’s leave humidity out . . . . .

Time is a function of RPM.
We also have CID, VE, and RPM. You can control these variables to a large extend. Well there are limitations, but you know what I mean;
You decide the operating RPM
You decide the CID You decide/improve VE
You can control most of the variables, except temps, the most difficult variable.
Cooler temp before the turbo is your friend.

Heat / Energy!
Hotter temps at the end of the combustion (to an extend) are your friend. The speed at which the temps rise create pressure . . . multiply thay by piston area and stroke and you have torque . . . add RPM, you hve HP.

A cold air kit gets you to ambient. Since we are not talking about alky, that is the best you can do, unless you design some kind of venturi, but that limits flow to be of any practical benefit.

So how do we favor cooler temps between turbo and intake?
-Efficiency
-Conduction
-Heat of vaporization

Efficiency . . . On the intake side . . . . .
A turbo that is matched to the most efficient operating parameters (read: operates at high efficiency) will result in a cooler air charge.
We know that compression of the air creates heat, 11Deg F / lb boost.

Every restriction in the inlet of 1 inHg increases charge temps 8 deg. (Calculated)
Every 11 Deg. F is worth about 1%. Meaning . . . you change the temps 11 deg you get -1% or +1% HP increase.

Conduction –
The intake (read heat sink) will reduce charge temps for a little bit depending on the heat energy available.
After some point, the heat transfer diminishes . . . . happens quite rapidly.

Heat of vaporization –
E-85 is a perfect option! Since you spray 30% more, the temp drops quite a bit.

Air Friction
Friction increases temp, but I think these are to some extend negated by heat transfer.
This is just a theory. Since it is a small part of the intake charge heat, I like to focus on the bigger parts.

Again . . . "off the cuff" . . . not a lot of thought put into this . . . . typing what comes to mind . . :eek:
 
So . . . . since alky injection is off the table you can tap into the shraeder, add a small M5 nozzle, and spray to cool the temps at XX PSI. LOL!

You can also add water . . . but you need a really small nozzle . . . Water expands about 3500 times it’s volume when the state changes to steam. . . . so personally, I would not go more than an M1. I have no grounds for this other than gut feel.

One idea of mine is . . . encapsulate the intake (weld a skin over it) and flow CO2 through it. It must be baffled to create surface area, and for balanced CO2 flow . . . There are many other things you can do . . . . just have to keep thinking . . . :cool:
 
AL heads increase VE over steel heads, and reduce detonation tendencies by carrying heat away.
But . . . if the heads are not the flow limit on the set-up, you will not get the VE benefit.
 
So how does one find out what turbo is best for their given application to keep temps down?
 
Lets keep this topic to lowering the charge temp without spraying water, meth, N02 etc. Straight HOTAIR.

We can talk pre turbo alky, water, nos etc in a different thread for now lets talk about getting the coolest charge possible without these items. Once we figure out how to do this then lets talk about thing like water alky nos to lower the charge temp even further
 
Boost231 said:
So how does one find out what turbo is best for their given application to keep temps down?
Click to expand...

Let's review turbo efficiency . . . . . In general terms;
Say you run a HA at 5500 rpm, PR 2 (15 PSI boost), the car should run about 110 mph converter locked.
That equates to about 12.0x in a 3500 lb car, 358 WHP.
It requires around 40 lb/min of air.

Now that we have PR=2, 40 lb/min, we can look at a map.
You want to be in the center island for the highest efficiency.
In this example, the atatched map indicates the turbo is in it’s highest efficiency range.
I would guess about 74% efficiency.

Easy part is the calculation. Finindg a map that will work in the full rpm range is tasking.
You just have to look at all the maps and make a determination.

If you study tis map, you will notice that the rpm is real low for the mass flow.
What this means is that it builds boost sooner. Now you can use a larger turbine to lower BP, and a tighter converter for coupling.

This is the wheel in the HA core and while it is in the smaller housing which inhibits full potential, it is perfect for the goal.
Only testing will tell the story, but it is a calculated guess which reduces frustrations. :rolleyes:


FI62map.jpg
 
Aj's next door and on the border but maybe we could get him to defect to Texas from NM.:D

Can anyone tell Jerryl's an engineer yet.:p One of the biggest issuesthat any HA has id the design of the intake. Aj's already proven the fact on a C/T set up by using an after market 4 barrel intake. Gutting an SFI intake gives way to much volume so you end up with some other issues, one of them being turbo lag. On an SFI intake you'd be better off with one of the FWD intakes adapted to the HA design which will reduce the air temps due to the fact that the IC cars use one like it which keeps the intake top isolated from the base and lets it run cooler. On the C/T cars it means going with an after market intake for a 4 barrel like Aj's done or gutting the 82-83 intake which increases volume but reduces internal area.

On the turbo what's needed is a higher volume at a lower boost level which, as Jerryl said, increases total power with out adding as much heat as the stock unit. The TA33 does offer almost twice the volume of the stock turbo but with the intake like it is on the SFI units it's only good for so much because of the internal restrictions. Now if you went with 1 of the FWD SFI intakes with a TA33 then you should notice quite a bit more power since the restirctions would be mostly removed. On the other hand the C/T intakes need more area to reduce restriction and increase flow, which they're lacking.;)
 
^ edit that before i smack you. :) so send me the map i need via email
 
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