Motorsports ? : Blower & Intercooler

[ChrisV]

Hi All,
A while back I asked the forum about posting some motorsports questions and I was given the thumbs up so here is the first of a few.

I road race an 87 Mustang with a blown 306 (worked lower and upper), it has an old SN89 Paxton on it and was wondering about plumbing in an intercooler. Paxton does not make a kit for this older blower, so this would be totally custom. Any thoughts? resources for the equipment?

Chris

[Mike W]

Hi Chris, you brought back memories. I had a Paxton on my 65 Mustang. I used to watch the vacuum guage go to zero and then the pressure guage would climb up to 5 psi. I finally sold the Paxton, still have the 65.

[BADSBRD]

You will need a bunch of tubing, and you can either get a new intercooler or try to find one off a semi. If you want new sheck out Spearco or ATI for an intercooler. If you are a good welder you can always grab a couple intercoolers from some imports and combine them together. There are some good sites I listed below. Most of the turbo guys made their own plumbing and can probably offer some more suggestions.

How much boost are you running? Do you think you will see much a difference in performance with the intercooler? There are plenty of 600-800 HP cars running around without an intercooler. I run a 302 in my Thunderbird with around 600 HP with a Vortech YS blower.

Some sites of interest:

http://www.toohighpsi.com
http://www.turbomustangs.com
http://www.hardcore50.com
http://autos.groups.yahoo.com/group/jyturbo/

[ChrisV]

Badsbrd,
Thanks for the info, I am only running 6psi (around 450HP) but with road racing the blower is getting really hot so I thought an intercooler would give me more power and durability for the blower life. I thought it would be a good project but if it will have no benefits then I will wait until I can get a new blower.

Chris

[joe_dejesus]

ChrisV,

you will benefit from an intercooler simply because it will lower the temp of the pressurized hotter air... and that by itself will make air cooler and more dense... keep in mind intercooler and tubing will add a few more pounds to the nose of the car and might affect your weight distribution..


go to the salvage yard and snag in intercooler of a turbo equipped car or truck (F250 power strokes) and take it somewhere and shorten the core to fit your application.. the plumbing will be easy to retro fit...

gotta love boost I know I do....

[BADSBRD]

You will probably see an increase in HP, and lower intake temps. But will it be enough to make up for the extra weight, and the lower boost? Hard to say, but it can't hurt to try. Intercoolers on drag cars can make a difference. Comparing a Drag radial car with a Renegade car is a good example. The Drag radial class is allowed to run intercoolers and go about .50 seconds quicker in the 1/4 mile....but they are also running 25 + PSI of boost. Their intake charges see a big drop in temps with that much boost and an intercooler.

[Blown S-10]

an intercooler will do nothing for blower life.

[dumbass]

You need to know more about the setup to give an accurate answer. Im mainly familiar with turbo charged systems but a blower is still forces induction (w/compressor but no turbine). Knowing that the increase in pressure causes a proportional temperature increase the amount of boost you are running will determine if you need an intercooler. If you are low boost the pressure lost from the cooling of the aircharge may negate the gains you would see from the lower air temperature. At low boost there is less compression of the intake air from the compressor so there is lest increase in temperature. Therefore there is less change in charge air from ambient air temp and the cooler is less effective. However at a higher boost level the intake air can be much higher than the ambient temp and the intercooler can work most effectively. Ive seen turboed engines at 7psi without intercoolers w/ no problems. Another option to consider is a cold box or dry ice on the manifold after the compressor to cool the charge air. This is good if you only "need" it for a race and you can put it under the hood right before you are going off. Good for the strip not really for the "street". Im not sure how orginized your "street" racing is nor do i want to hear about it but the dry ice on the intake is cheaper than the intercooler and more effective because you can potentially reduce the intake temps to below ambient temp in the summer and have a thermodynamic advantage over the other guy.

[ChrisV]

All,
Thanks for the info! I think I am leaning towards giving it a try. I will price out the parts and determine if the costs are worth it. If I go ahead with it I will do a before/after on the dyno and publish the results.

In the next few months I will be working on the racecar to get it back on the track, so I will have some more motorsport questions.

[JnJSpdShop]

Badsbrd,
Thanks for the info, I am only running 6psi (around 450HP) but with road racing the blower is getting really hot so I thought an intercooler would give me more power and durability for the blower life. I thought it would be a good project but if it will have no benefits then I will wait until I can get a new blower.

Chris

you mentioned blower life, is this paxton self contained or oiled off the engine. If it is self contained paxton used to sell an oil pump that replaced the stock dip stick/plug and it included a small oil cooler like a tranny oil cooler to keep the blower oil temp down. If the blower is oiled off the engine you can add a small like power steering cooler before the oil gets to the blower, and also add a HD engine oil cooler

[Teeps]

Bottom line is temps at your intake inlet.

As you crank up the boost, depending on backpressure in the system, and the efficiency of the blower your running (some are worse than others), you will start to see higher and higher temperatures at your intake inlet. This forces you to retard the timing, and causes the combustion mixture to expand, and lessens the potential force of each combustion process.
It limits how much further you can go with the bost, timing and A/F ratio.

Air to Air intercooler is very effective, but a Water to air is more consistant, (might be better for road racing, up to you).


I can tell you this, you can run boost levels higher, advanced the timing further, and lean out the A/F mixture further (assuming you have a stout short-block), much more safely with an intercooler. (Road race you don't want to go nearly as lean as a drag car).

Overkill on an intercooler will only cause a little pressure drop, which can be overcome with more boost (assuming your belt can still grip that small pulley).

Not only does an intercooler or aftercoooler buy you some safety margin, but it allows you to go further with the tune, and the boost, and this you will make more HP. Even with no settings changed, you will make more hp, more consistantly. With settings changed you will make alot more hp.

I'm far from an experienced tuner, but I know a couple, and I have seen some results first hand on a chassis dyno.

I saw a car with a maxed out eaton roots blower (fuel injected SOHC motor), (super hot discharge temps) add an intercooler and it gained over 80 hp at the rear wheels (chassis dyno). This setup had alot to gain, because of the poor efficiency of the blower, especially being over-revved.

It was a night and day difference on that car, it really woke up the combo.

They decided to take it a step further for the track, eventually they added fittings to the intercooler and ran the A/C through the heat exchanger, and they got 140 rwhp boost over the non-intercooled numbers.

They also were measuring the temp differences at the intake runner (after the cooler, and I don't remember the exact numbers but it was somewhare around an 80 degree difference without A/C on, and way cooler with the A/C).

Some guys use an Water cooler,and add ice to the tank when they go to the drag track, this drops the inlet temps to suprizingly very very cold levels, and helps make tons of power, (make sure you have plenty of fuel for that ultra dense air).

Again it depends on how efficient of a compressor your starting with, but I have never seen a compressor setup that couldn't benefit from a cooler (assuming your running higher with the boost levels). If your just running a very efficient compressor, at very low boost levels, then your not going to see the same types of efficiency problems.

[ChrisV]

JnSpdShop
You are correct there is an oil cooler for the older Paxton's, but I have had no luck finding it and I am almost certain Paxton does not sell it anymore.

Teeps,
Thats great info, Thankyou. It seems as though I may have to give it more thought based on the low psi I am running (only 6psi). Unfortunatley the older Paxtons (SN89) do not benfit from changing the pulley to get more boost, atleast this is what I have been told.

Now Im thinking of looking for a bigger head unit that will give me more boost therefore making the intercooler worth the effort. Either way it would still be a good project.

Hey Teeps, can you recommend any books that go over A/F mixture, timing, back pressure and all that? I would really like to read up on this get into the heart of it all as I plan on doing all this work myself.

[Teeps]

Yes there are a few good books out there,

Corky Bell has a few books on forced induction. (search amazon based on Author name, to get the exact titles) They will be a bit basic in nature but a great start, and Corky was the turbo man.

Also as far as tuning goes, these guys are the best.
www.superchipscustom.com (notice the "custom", although they are backed by superchips they are a complete seperate company, total custom tuning)

And this is their book.
http://www.modulardepot.com/product_...roducts_id=178

Great resource for tuning, however it there is also information helping a tuner to use their software, (won't help you if you don't have their software), The greatest tuners in the U.S. I have ever worked with, (I know most of them and these guys have always been the best (engineer used to work for Ford and Roush, worked on cars like the Cobra R, lightning, cobra, tuning ECU's for special projects, trans controls as well.) They have tuned more cars than anyone, and have developed a huge database of custom calibrations for et'all.

As far as boost,

An engine is a big air pump the more air the more power, the more compression before combustion, the more force and more power.

A blower just helps get more air in there, spinning a blower faster can help do it even better, but some blowers will get inefficient at higher speeds, causing the air to heat, and expand, and thus the less dense hot air will not make more power, and require retarded timing. So sometimes more boost does not mean more power, intercooler or a more efficient compressor help with this.

Good luck!

[Blown S-10]

if you don't have a "wideband o2" . get one and use it.

[Teeps]

if you don't have a "wideband o2" . get one and use it.

Yeah, I built my own,

He speaks the truth, you cannot tune a blower-car without ECU / sensor datalogging, and a wideband 02 meter to measure your a/f ratio.
Well you can try, but your going to be wasting alot of time, and with not very good results.

You don't have to build your own though, the same site that sells that book (and many others) sell the test equipment for very reasonable prices.
(used to be 1000-2000++ range for a good meter).

If your not confortable tuning, ask SCT to do it, they will send you a calibration and device after you get your hardware installed, then you can attend one of their dyno-tuning sessions to get your setup fine-tuned.