ok I dont have the installation manual for the paxton but can you put it after the paxton before the intake or does it have to go before the supercharger on its intake side? it looks like there is room to do it to the drivers side of the throttle body but can it take the pressure? it would solve a lot of hood clearance probs Im having with my harwood hood making the cowl system work.
thanks in advance

 

On my Paxton kit for an '87, the MAF is placed on the inlet side of the supercharger. I'm going to make a bold statement and assume it would be the same for an '89 (but not positive). As for putting the MAF on the discharge side, that's where ATI's kit locates it to. So the MAF can take the pressure.


------------------
Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
Former Paxton (6-psig): 12.57 @ 111 mph.
Former Paxton (6-psig) & former 50-hp nitrous: 12.04 @ 114 mph.
Current ATI D1SC (Initially 10-psig): Projecting high 11's.
Future ATI D1SC (15-psig): Gotta catch them pesky 26-psig boosted TTA's!!

http://willie.camaro-firebird.org/

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.

 

On the Vette paxton put it on the discharge tube. I am thinking of trying mine there, maybe?

 

I don't know anything about the Paxton kits but if you consider how the MAF sensor works then you might reach a conclusion.

1. The MAF sensor works by letting air pass across heated wires while measuring the voltage required to keep those wires at a constant temperature. The instrument is calibrated to standard atmospheric conditions. I seriously doubt that it's calibrated to operate with an air stream at 200+ degrees F. If the wires don't have to be cooled off, then the computer will think you need hardly any fuel and you'll run lean and have a piston melt down. So that answers half your question. Install it in front of the supercharger inlet.

2. You want the MAF sensor to be in a location where it measures the total air consumption but does not measure the volume of air circulated back from the blow off valve. You only want to meter the air once. The moral of the story is put it upstream of the blow off valve return. That's the other half of the answer.

Put it right behind your air cleaner . By the way, that's exactly where is was on my Vortech supercharged '94 Vette. And if Vortech and Paxton do things two different ways.... then Vortech is correct, period.


------------------
'89 Firebird
B&M Blown 468
Tremec TKO 5-speed
Strange 12-bolt
Kenny Brown competition suspension

[This message has been edited by QwkTrip (edited May 01, 2001).]

 

Ok I dont see how the paxton is going to put out air that is 200 degree's. If so then the manifold air temp sensor is going to go beserk and it will give the wrong info as well. The paxton shouldnt heat up that much or it would require a radiator itself just to keep it at operating temp and an intercooler for the air just as a turbo does. The pics that summit has of the paxton kits it appears that the MAF is after the paxton previous to the throttle body but I cant tell so thats why Im asking. If the outside air temp is 60-80 degrees or even higher as fast as its going through the paxton its not going to get hot enough, even through a 220 degree radiator, the air dosent get to 220 cause its flowing through it fast enough and the air in the paxton is going significantly higher.

------------------
'87 Monte Carlo SS,with '89 IROC 350,700 trans, blew up 3.73 posi stuck with crappy 2.73's neeed gears! hooker headers, flowmaster 2 1/2" exhaust true dualls, recently installed a set of alum vette heads 58cc, new cam for a paxton, recently installed paxton, OMG need a posi bad. So if anyone knows where a buick GN 8.5" rear is let me know.

[This message has been edited by monte-ss (edited May 01, 2001).]

 

Your theories are wrong. I'm a mechanical engineer and I can help you understand how and why it all works if you like. Then you can go tell your friends about all of it and blow them away . So sit back and learn all you need to know about superchargers.

You had mentioned that there is no way the air charge could get very hot through the supercharger becuase it's moving so fast that it doesn't have much time to heat. That's not how it works. Time has nothing to do with it.

The supercharger takes air at normal outside pressure (called atmospheric pressure) and increases the air pressure to the 'boost' level that you're used to hearing about. When the air gets pressurized through the supercharge it also increases in temperature and it happens almost instantly. The temperature increase doesn't come from heat transferred from the case of the supercharger, it is generated simply because the air increased in pressure. It's a property of physics. You just have to accept it.

The air will likely be in excess of 200 degrees F. One way to demonstrate this to you without doing the math is to think about the way an intercooler works. A typical intercooler will drop air temperature 40 degrees, right? If the engine coolant is pumped through the intercooler to cool the supercharged air and the coolant is at 200 degrees F, then the air has to be a whole lot warmer then that. This is normal.

Now the entire purpose for the intercooler is to reduce the air temperature. But why do you want to do that? It's so you can get more air particles into the engine. I'll explain. Remember how when the air is pressurized by the supercharger it heats up? Well, another thing that happens when air is heated is that it expands. A jar full of air at 70 degrees F has a certain amount of air particles in it. If you filled that same glass with air at 200 degrees F there would be a lot fewer air particles actually inside the glass. Air expands when heated. Once again, that a property of physics and you have to trust me on that one. Now let's apply that idea to the engine. The cylinders are now the glass. You can fill the cylinders with hot air and burn a little bit of gas or you can cool off the air with an intercooler and fill the cylinders with cooler air and get more air particles in there allowing you to burn more gas. Burning more gas will allow your motor to make more power. That's why you use an intercooler.

When I told you where to mount the MAF sensor I also tried to explain why so you would see the benefit to doing it that way. Just because Paxton does it a certain way doesn't mean it's the best way. If you just have to know then try both. Also, how much boost are you using? There are several things that need to be done at certain boost levels that the Paxton kit doesn't provide you with. You could really end up hammering your motor if it's not done right.

 

QwkTrip Your obviously a Paxton basher, hey that's OK, to each his own. Now explain why the BEST Supercharger Builder ATI (not Vortech) puts the MAF in the discharge tube, and you can leave Paxton out of it.

 

That too is an oppinion. It's hard to read body language over the internet so I don't mean to be rough on you but my first response would be - if you know the reason then spit it out. I provided help along with explanations in my posts and not open ended comments. I ask you to do the same. If you're simply asking an innocent question, I'm going to stick with the same answer as before.

I'm pleading ignorance about the ATI kit but my first question would be which kit? How much boost are they putting out? Is there a blow-off valve? What do they do with their serious setups? Is the MAF sensor a stock unit or is it supplied in the kit? I'm curious and I don't know. My concern is that the factory MAF sensor placed on the downstream side of the supercharger will cause the motor to run lean because it's not calibrated for those temperature ranges.

Just because they give you a kit built a particular way doesn't mean it can't be seriously improved on. For instance, an FMU is often supplied with supercharger kits but it's a TERRIBLE way to supply fuel. It's a temporary bandaid at best. A local guy here bought himself a brand spanking new Saleen 351 supercharged 'Stang. It's a Saleen... what could be wrong? Well, they used an FMU with a T-Rex booster pump and it overran the capabilities of the stock in-tank pump. This created a vacuum in the fuel line and the car sputtered, spit, and ran lean under power. Removing the T-Rex and factory pump and replacing it with a different in-tank pump solved the problem. That wasn't part of the kit and Vortech wouldn't have told you to do it that way.

 

I've owned a Paxton and currently own a D1SC from ATI so I feel qualified to answer all your questions.

Both P1 and D1 kits are available for third gens. The P1 puts out up to 12-psig on a stock 350, while the D1 can take it beyond your wildest dreams.

Both kits incorporate a by-pass valve. ATI does not refer to it as a "blowoff valve". It is a 1-1/2" tube that connects the discharge and intake of the blower through a butterfly valve that closes under boost conditions.

The MAF used is the stock piece. It is mounted on the pressure side (between the intercooler and throttle body. On my AutoXray scans, I see no difference in airflow values on this setup in comparison to readings I've recorded with my Paxton where the MAF is positioned before the blower.

Maybe ATI locates the MAF on the pressure side because of the effectiveness of the intercooler?? I've seen an appreciable difference in intake temperatures between the ATI and Paxton -- to the tune of 50 degrees or more.

Agreed. I was able to buy my D1SC kit without the FMU through Tenacious Performance (and the best price too). No other distributor I asked would allow this because the kit is considered a "package" deal. Ha!!

I use Carroll's Superfueler system to supply the additional fuel. This is accomplished without increasing fuel pressure, but by adding three supplemental fuel injectors that are electronically controlled.

------------------
Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
Former Paxton (6-psig): 12.57 @ 111 mph.
Former Paxton (6-psig) & former 50-hp nitrous: 12.04 @ 114 mph.
Current ATI D1SC (Initially 10-psig): Projecting high 11's.
Future ATI D1SC (15-psig): Gotta catch them pesky 26-psig boosted TTA's!!

http://willie.camaro-firebird.org/

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.

[This message has been edited by Willie (edited May 02, 2001).]

 

That's really interesting. Apparently GM built a lot of flexibility into their MAF sensor. That's exactly what we needed to know, Willie. Thanks .

 

Well first of all I must say excuse me for my ignorance I have been spending more time lately on iterrated integration second differentiation and differential equations. I was not thinking of all the gas laws such as boyles law and others I cant recall the names to at the moment.

Yes you are correct about the temp changes however as I stated before I dont see it getting that hot cause I didnt see them hit those kind of temps with my scanner for what the MAT sensor read.

------------------
'87 Monte Carlo SS,with '89 IROC 350,700 trans, blew up 3.73 posi stuck with crappy 2.73's neeed gears! hooker headers, flowmaster 2 1/2" exhaust true dualls, recently installed a set of alum vette heads 58cc, new cam for a paxton, recently installed paxton, OMG need a posi bad. So if anyone knows where a buick GN 8.5" rear is let me know.

 

Come on guys.... we've got a good topic here with good information. Don't take anything anyone writes as a personal attack. Just stick to tech stuff... We're all in this together to try and help one other out, remember? We're not here to accuse and call each other names -- that's a total waste of energy.

Willie

 

Sorry if I insulted you. That was not my intention at all. I read your reply and it seemed as though you were very confused about the relationship between temperature rise and pressure. I tried to present some information for your own benefit at a level at which I assumed you were at. I appoligize if it came off as a put down. Believe it or not it took a lot of effort to explain those things without getting into technical details. I'm sure you can empathize with that . In fact, some of it probably doesn't even make sense because of all the info I had to leave out! LOL! What are you studying in school? Sounds like you're heading towards engineering.

 

Qwick, not going for an engineering degree, rather a computer programming degree but by the time I get there I wont be far off of an engineering degree or mathmatics degree. Dont mean to sound "pissy" but its almost finals week for a calc 3, diff eq and physics,(and this is the shortest semester ai have taken!) and I grad this semster to move on to finish up for the bachelors I do apreciate the tips and understand exactly what you are talking about I have gone into some of the Gas relationships in my physics and chemistry classes. Just trying to get too many things done with not much time. I do honestly appreciate all the help. Hard to imagine a computer expert and car fanatic! maybe Ill also get into burning my own chips later on.

thanks again guys for all the tips or for giving someone else the opportunity to ask some related questions.

------------------
'87 Monte Carlo SS,with '89 IROC 350,700 trans, blew up 3.73 posi stuck with crappy 2.73's neeed gears! hooker headers, flowmaster 2 1/2" exhaust true dualls, recently installed a set of alum vette heads 58cc, new cam for a paxton, recently installed paxton, OMG need a posi bad. So if anyone knows where a buick GN 8.5" rear is let me know.

 

Hey, you'll have a brighter future in computer science then I will in mechanical engineering. Good choice. I'll tell you what.... Maybe sometime you could help me figure out how to operate my fuel injection system. I'm not exactly the brightest bulb in the pack when it comes to computers

 

Hey Quick Im still learning as well, when I put this car together I got real lucky and got the GM service manual on the 89 camaro's this thing is huge! and its written so any "idiot" can work off of it, makes you wonder why a goodwrench mech makes so much money other than the fact they are workin for the dealership. but I can try to help as you have me.

------------------
'87 Monte Carlo SS,with '89 IROC 350,700 trans, blew up 3.73 posi stuck with crappy 2.73's neeed gears! hooker headers, flowmaster 2 1/2" exhaust true dualls, recently installed a set of alum vette heads 58cc, new cam for a paxton, recently installed paxton, OMG need a posi bad. So if anyone knows where a buick GN 8.5" rear is let me know.