Installing Imagine Automotive Super Charger on my 1998 2.5 Boxster

[drbodzin]

Originally Posted by The Radium King

solder is not designed for situations where mechanical work is being done (ie, opportunity for wire to bend); better off with a crimp, as well as some support for the resistor leads (they will break if worked also).

bigger power puts out bigger heat - think about a 's' third radiator, 's' oil cooler and, possibly, an intercooler to manage the extra heat you will be making.

take a look at how the kit handles vacuum. it looks to me like a 'blow through' system (as opposed to suck through) where the sc is blowing through the throttle body. this means that the location where the aos normally takes vacuum from no longer works (will be pressurised by the sc). you can draw vacuum from the sc intake, but you probably don't want to be sending a lot of waste oil through the sc. what I've seen on the tpc sc kit is that the aos just dumps to a catch can. this is a viable solution except don't race on my track, as I don't want your car puking oil on the track from an overfull catch can. also, with the catch can method, you no longer have vacuum on your crankcase and what I've read indicates that the piston rings require the pressure differential to work properly.

otherwise, the resistor is a hack to avoid getting an expensive tune. I think the bettor solution is to let the maf do its job and pay the money for a proper tune. apparently the oem injectors are up to the task, and 2.5 headers are easily improved (provided there is room allowed by the sc; with the tpc kit the sc location only allowed the use of 2.5 headers even when installed on a 3.2 which really killed power for the larger engines to the point where folks were getting no hp gain after the install). so, i'm not saying don't do it (FI is cool) but understand the implications and trade-offs. iA was only in business for a year or two, so consider their product accordingly.

ps, if you wish to avoid the smog pump relocation issue, just get your indy to push a 'rest of work' (ROW) tune on your car - removes requirement for smog pump and secondary o2 sensors (and you can start your car without depressing the clutch); takes about 7 minutes. uncertain what your smog testing requirements are, but gonalaus on this forum successfully passed smog in Chicago with a row tune and smog pump deleted.

Thanks for thorough reply.

I will review my solders and determine if they should be redone with crimps. Thanks for that.

I already have the third radiator and larger oil cooler installed. Nothing I've read to this point says a SC needs an inter cooler. Only mentions the need for turbos. But I will keep that as an option should the temps demand it.

I already have headers and performance exhaust. Only thing I haven't done it replace the Cats. Was thinking of the Fabspeed 200 cell cats. But I can't find any reviews online as to whether they had any HP impact. Everything just says they make the "sound" of the exhaust better.

Regarding the vacuum, I will post more info on that later when I get to the tubing install. Maybe more advice can be given then.

I am in CA, so SMOG is more restrictive. Doubt smog would pass here without the air pump. Already got the unit moved and installed.

Should be doing more work on the next few days!

[Topless]

Originally Posted by drbodzin

Thanks for the thorough reply. I've confirmed that the pulley on my SC is 4 inches. Glad to know there's the option to send the ECU to GIAC to flashing. I was making the assumption I would have to bring the car to a tuner.

Anyone have thoughts on that?

From others past experience I recommend a live dyno tune to get A/F ratios and ign timing exactly right based on your chosen fuel and setup. FI on a Boxster has a very narrow tuning window between making more power safely and connecting rods sticking out of awkward places. Tuning is not where you want to save money with a off-the-shelf solution. IMHO

This car will definitely not be "street legal" and subject to impound in CA due to CARB anti-tampering laws requiring unmolested intake and exhaust, but it may actually pass a smog inspection if the tech is unaware of your changes and it runs clean with functional cats. Welcome to commiefornia.

[The Radium King]

compressing the air will heat it. the location of the sc (typically near the exhaust where there is room in the cramped boxster engine compartment) will cause heating/heat soak. increased intake air temperature (iat) is detrimental to performance; it's one of the primary inputs the ecu monitors to determine fuel delivery. aside from performance, anything you can do to remove heat from the system (air, oil, coolant) is good.

edit to add - uncertain where iA located their sc, but if near the exhaust, consider (a) wrap or ceramic coat the exhaust, and (b) blanket for the sc (I think a turbo blanket could be repurposed for your sc pretty easy).

initial boxster forced induction kits didn't have intercoolers because there was nowhere to put them without hacking the car up (ie, no longer a bolt-on procedure for the weekend warrior). when porsche added the third radiator in 2000 then the tuners started repurposing these for use in air/water intercooling systems. the same thinking applies to tuning; the bosch 7.x dmes took a while to break; until then the forced induction kits addressed the change in fueling requirements with hacks like 7th injectors and resistors in the maf wiring, etc. now that we can tune the oem ecu there is no real need (except cost) to mess around with sub-par solutions. note that piggyback computers have also become quite sophisticated in the past 15 years; a wideband 02 sensor tied to a piggyback might do the trick for you also - check with insite or jaay about their experience with these.

[JAAY]

Make sure that you put a wide band 02 sensor gauge in ASAP. You will want to know what is going on. I used a apexi afc to tune in my afr's. This will basically take the place of that resistor. FYI, my motor melted a piston or a valve with the kit, not to scare you. I was tuned to 11:2 afrs. which I feel was safe.

[BYprodriver]

The "S" engines have forged pistons, other engines have cast pistons.

It would be good to have the injecters cleaned & tested to enhance fuel flow & remove a likely variable to inevitable problem solving. Test fuel pressure at the fuel rail too.

[JAAY]

Originally Posted by BYprodriver

The "S" engines have forged pistons, other engines have cast pistons.

It would be good to have the injecters cleaned & tested to enhance fuel flow & remove a likely variable to inevitable problem solving. Test fuel pressure at the fuel rail too.

Really? That I did not know. You always surprise me with your knowledge.

[JAAY]

BTW This is what I used for my O2 bung. I love the fact I didn't have to weld and it works perfect with my fabspeed midpipes. I also am using the aem uego gauge type for monitoring.

AEM No-Weld O2 Sensor Mount 1.75-2 inch exhaust

[drbodzin]

Originally Posted by The Radium King

compressing the air will heat it. the location of the sc (typically near the exhaust where there is room in the cramped boxster engine compartment) will cause heating/heat soak. increased intake air temperature (iat) is detrimental to performance; it's one of the primary inputs the ecu monitors to determine fuel delivery. aside from performance, anything you can do to remove heat from the system (air, oil, coolant) is good.

edit to add - uncertain where iA located their sc, but if near the exhaust, consider (a) wrap or ceramic coat the exhaust, and (b) blanket for the sc (I think a turbo blanket could be repurposed for your sc pretty easy).

initial boxster forced induction kits didn't have intercoolers because there was nowhere to put them without hacking the car up (ie, no longer a bolt-on procedure for the weekend warrior). when porsche added the third radiator in 2000 then the tuners started repurposing these for use in air/water intercooling systems. the same thinking applies to tuning; the bosch 7.x dmes took a while to break; until then the forced induction kits addressed the change in fueling requirements with hacks like 7th injectors and resistors in the maf wiring, etc. now that we can tune the oem ecu there is no real need (except cost) to mess around with sub-par solutions. note that piggyback computers have also become quite sophisticated in the past 15 years; a wideband 02 sensor tied to a piggyback might do the trick for you also - check with insite or jaay about their experience with these.

Thanks for the suggestions on controlling heat. I will wrap my header for sure.

[drbodzin]

Originally Posted by JAAY

Make sure that you put a wide band 02 sensor gauge in ASAP. You will want to know what is going on. I used a apexi afc to tune in my afr's. This will basically take the place of that resistor. FYI, my motor melted a piston or a valve with the kit, not to scare you. I was tuned to 11:2 afrs. which I feel was safe.

When you say "wide band 02 Sensor Gauge", is this what you mean?

Apexi SAFC Air Flow Converter from AlamoMotorsports

Also, if you use this "wide band 02 Sensor Gauge", do you still need to get the ECU reprogrammed? Tuning is fairly new for me.

When you day you melted... with the kit, do you mean the SC kit or Apexi?

So from what I am hearing here, the resistor is s hack and the wide band sensor gauge is a better solution. Am I correct in that?

[The Radium King]

did some research on the iA sc kit; the resistor is there to scale down the maf output (otherwise it would be outputting a meaningless max signal most of the time given the increased airflow from the sc). it is designed to work with a custom giac tune and larger injectors. link here:

Imagine Auto 2.5L Supercharger is Live! - Rennlist Discussion Forums

without the tune, and with the resistor in place, your engine will think it is getting less air than it really is and operate in a lean condition. not good, as the engine needs the fuel to keep things cool. get the tune, or get a wide band and piggy back - cost is about the same once you factor in tuning.

[The Radium King]

fyi, your computer (ecu, dme) does two jobs - trigger the spark plugs (timing) and trigger the fuel injectors (fueling). internal combustion works best with a ratio of air to fuel (afr) of 14:1 (stoichiometric). the computer uses the mass airflow sensor (maf, a hot wire that changes resistance with airflow) to determine how much air is entering the engine (which is controlled by the throttle body - a butterfly valve connected to your gas pedal) and then calculates how much fuel to provide based on programmed tables called maps. under low load your computer tries to maintain an afr of 14:1 for best efficiency. the oxygen (o2) sensors on your exhaust can determine if you are at 14:1 or not; it is a narrow band o2 sensor that puts out a large signal when the exhaust gasses indicate a 14:1 mixture, and a very small signal if the mixture is lower than this (rich - more gas than needed) or higher than this (lean - less gas than needed). if the o2 sensor thinks things are off then the computer modifies the maps (‘trims’ them) to bring things back to 14:1. at higher load/rpm, the engine should run a little rich (ie, as per jaay, 11.2:1). this is because the additional gas helps cool the pistons and valves in high output situations. a rich situation is much better than a lean situation where everything burns much hotter with the excess of o2 and holes get burnt in pistons, etc. when your car gets in a high load situation and wants to run a rich afr, however, the o2 sensors are of no help as they are narrow band and out of their operating range. in this case the computer just uses the maf signal and the programmed maps to set fuel levels (this is called open loop operation).

with forced induction (fi - turbo, supercharger) you can push the maf out of its operating range, or push the ecu into an operating area for which it has no maps. further, the additional power developed by fi requires richer operation to provide additional cooling. to address this you can reprogram the ecu as per iA, add a 7th injector as per tpc (a seventh fuel injector mounted in the intake manifold tied to an rpm switch that triggers additional fuel when a certain rpm is exceeded) or go wide-band.

a wide band o2 sensor has a much larger operating range than a narrow band o2 sensor and can return a proportional signal through all potential afrs. with one of these connected to a piggyback computer you can do real time (closed loop) fuel management all the time and not just at low load stoichiometric. a piggyback computer is a device that intercepts the maf signal (and rpm signal, and other inputs such as intake air temperature depending on the model) and sends the main computer a modified signal designed to maintain whatever afr you program into it ... which means you have to program it ...

so, your call. get a $1000 tune from giac or softronic, or buy $750 worth of sensors and computers and a whole bunch of dyno time to diy.

[Nine8Six]

From a Super Cool & Charged thread powered by Top Quality Knowledge Sharing in no time. What a blast this place, forum.

Happy thanks giving to you guy down there!!!

TRD, happy everything up there

PS: I still dream of doing this mod. As much computers or sensors it needs lol. It's just so damn hard to find a complete package..... I've never really been able to put a proper kit together myself and kept-kept-kept hearing conflicting info

definitely subscribed

[JAAY]

Afc is to add or remove fuel. It works by tricking the mass air into thinking it's getting less or more air. This is helpful to keep your air:fuel ratios safe. You need the wide band 02 sensor and gauge to monitor ratio. Best to have it tuned by someone who is good with this stuff. Afc stands for air fuel controller. My motor went because I wasn't monitoring it at the time. I put in my afc and gauge when I did my 3.4 swap. I used to use these simple piggy back systems back when I had turbo cars.

[The Radium King]

yeah, the resistor is the first step in this. resistors in the maf are used in two ways; in a fi application they are a scaler that pulls the maf output away from the upper limit of its operating range and into the middle. of course, the computer has to be told this via programming. the other way tuners use the resistor is to lean the mixture - the resistor reduces the voltage signal sent to the computer, computer thinks there is less air than there actually is and delivers less fuel. at low load operation this is noted by the o2 sensors which trim the maps to bring things back to 14:1. at high load operation there are no checks, so the engine will run leaner than designed. if the resistor is sized properly then you see high load operation at 14:1, get more power, use less fuel. all good, except that your engine is now running hotter, the computer starts to pull timing to try and fix it and, if it can't compensate adequately enough, things break.

when you buy a standard 'off the shelf' tune this is all that is done as well; the tuner just modifies the maps to run closer to stoichiometric during high load operation. more power, less fuel. in this case the tuner also has the ability to fiddle with timing to try and bootstrap the issues created by running lean during high load. the other thing a tuner can do is increase the rpm limit. if power increases with rpm then increasing the rpm limit gets more power. porsche set the rpm limits to protect engine internals, however, and increasing these limits has the opportunity to break things in new and innovative ways.

going back to the resistor, the best way to do it is to use a variable resistor (potentiometer) and set the resistance value based on feedback from a wide band o2 sensor so that you are getting the afr you want. the problem is, a good resistance for one situation may not be the best for another, so you should be constantly varying the resistance to achieve optimal results. this is what a piggyback computer does - you program the afrs you want into it, and it varies resistance accordingly.

a final point on high and low load. I've been associating high load with high rpm, but you can get into a high load situation at low rpm. the computer also monitors throttle position (TPS) so if you are in a situation with the throttle wide open (WOT) but rpms remain low (i.e., going up a hill, pulling a trailer) you are also in a high load situation. often you will see WOT used instead of high load to talk about the various maps and tuning. note that if you put a resistor on your maf so that the computer thinks less air is getting in than really is, the computer will look at the tps, see that it is WOT but think that there is not much air moving, and default to open loop operation sooner that it would have otherwise.

anyway, a bit of a hijack, but wanted to get you the whole picture on tuning so that this sc install is a success.

[drbodzin]

JAAY and Radium King, thank you so much for your input. Both help a lot.

So it sounds like I can either:

1. Install the Wide-Band O2 sensor and use a Apexi AFC and have an experienced tuner set the programming.

OR

2. Have a DME reprogrammed. Do I still need to use the Wide Band O2 sensor with this option?

Is the resistor used in both 1 & 2?

For the wide-band O2 sensor, are you replacing the stock ones, or adding it as a 5th sensor?

[JAAY]

For me I had a boost gauge. If I were you I would have a boost gauge and the afr gauge with the 5th sensor. I like to know what is going on at all times. I'm a control freak.

[The Radium King]

giac should have the tune 'off the shelf' for you given their work for iA. from what I can find out the resistor is required for the giac tune. if you go piggyback then the resistor is replaced by the piggyback unit. either way, as per jaay, you should want to keep an eye on things and monitor boost and afr. boost can vary due to failing sc, belt slippage, wrong sized pulley, etc., and if you are not getting the boost you have tuned for you might have problems.

for the two gauges, pedro sells a duel gauge plate for your dash, and autometer sell a dual pod for your steering wheel. egauges.com is a good place to shop for gauges, and plx sell digital ones that can display a lot of additional data.

[drbodzin]

Thank you both for the clarification. That helps a lot.

Today I got under the car to start the install of the bracket that mounts on the can cover. Easily removed the header to make room to work.

On inspection of the cover, there are two areas (orange arrows) blocking the bracket. In the image from iA, the cover does not have these.

Seems the only way to get the bracket to fit would be to cut these off the cam cover.

1. What are these used for?
2. Any problem with cutting them off?



Photo from iA:

[The Radium King]

can't help you with those. I though they might be for mounting the mufflers on a 996 (i.e., common cam cover used for both engines) but, from the images shown here they are not:

Pelican Technical Article: Boxster Engine Conversion Project - 986 Boxster (1997-04) - 987 Boxster (2005-08)

i did note that the bracket appears to use the cam cover bolts to fasten itself. the Porsche procedure for tightening these requires that they get done in a certain order, so you might want to check that out.

[drbodzin]

Originally Posted by drbodzin

Thank you both for the clarification. That helps a lot.

Today I got under the car to start the install of the bracket that mounts on the can cover. Easily removed the header to make room to work.

On inspection of the cover, there are two areas (orange arrows) blocking the bracket. In the image from iA, the cover does not have these.

Seems the only way to get the bracket to fit would be to cut these off the cam cover.

Turns out I was able to grind off some metal from the bracket and it fit perfect.