Hi,

I am looking to add an IPD plenum to my 2001. I am also looking to add it to the Demon Speed on line store. But, only if it is worth it.

It has no modifications at this point, so this would be the first.

I need to get at the top of the motor anyway to change out those boost valves. The engine is overboosting (and underboosting).

So, I am looking for feedback on anyone who has done this already to see if it really gives the advertised 30 - 35 Hp prior to spending the cash on the part. (or carrying it in the store for that mater.

Thanks
Ed

 

i have it in the 68mm. it provides a noticeable improvement in mid range grunt/tq. i cant say it adds hp per se, and i would be very doubtful it met their white paper claims of +35hp? but it adds something and by no means is it money wasted.

that said, it is NOT the first mod to do on an appropriately staged upgrade list of complementary bolt on parts.

there is a reason a good exhaust and tune are generally considered to be the best "first" mods and then you'd add from there.

i like my ipd plenum though, i have to say.

 

Well, here is where I am at on this car.

I have had the car for about 8 years now. I have put a GT2 front nose on it and I have added wider 19" Victor Racing wheels. I have also added the H&R lowering springs. I think it looks fantastic like this. (I can post a picture if anyone would like)

However, I have never done anything to the motor.

I have not added any different muffler. I like that it is fairly silent with the stock exhaust. I am deathly afraid of spending $2k on an exhaust system that drones on the freeway. I have had plenty of Porsches that I have added exhausts to (79 930, 85 Carrera, too many 944's to count). I know that they can brighten up the performance of the car, but I do not want to pay the price in the way of sound that I do not want. If I knew what the tone would be and I could test drive the end result before I bought the system, then that would be a consideration.

Although it is tight and great looking, it has 90k miles on it. So, I am not thrilled about doing a 1 bar flash on the ecu or other mods like bigger turbos that might put more stress on the engine all the way around.

This is why this would be my first engine mod. I figure that the improvement would be from efficiency, not stress.

I am, however, open to suggestions.

Along the same vein, I have had DemonSpeed Motorsports for about 3 years now. I just bought out my partner which is allowing me to change directions of the company a bit. Up to this point we have focused our market on GT3 Cup race cars. I would like to diverge from this and include more products for the watercooled track and performance street group. (996, 997, Boxster, and Cayman)

I am looking to use my 996TT as a bit of a test bed for some of the items. We are also going to be embarking on a Boxster build as well to gain more experience with those performance parts as well.

So, any suggestions would be great as far as that goes too (as far as parts that would be good to carry in the store). I am going to be publishing a survey (which we would give a discount code for completing) in about a week which I will be asking this stuff too.

We are site sponsors here at Rennlist, so I will not get in trouble for the last bit.

Thanks

Ed

 

ed, think of this way. this car is DE-tuned as it comes from the factory. so adding another 100 with "bolt on's" is NOT gonna effect long term reliability. this platform is SOLID vis a vis power mods up to ( approx ) 550/600 crank. after that? depending upon tune/torque you are near rodbenderville.

also most "x pipe" designed exhausts will not "drone" the best bang for buck is the kline. see sambott here for the best deal in the CONUS. just don't tell him i sent you lol. it will NOT drone, i promise.

at this stage? my advice to you is that the ipd is a waste of time money to say nothing of the effort involved with wrangling that part in as its a VERY tight fit at the plenum lol. i needed a hammer.

 

the ipd is prone to leaking at the check valve on top. for a bone stock car this isnt a good mod to start with. if you want more power do a cobb tune with a different exhaust. look for a better clutch shortly thereafter and increase the size of your intercoolers. this will cost you in the ballpark of 7000$ and net you approx an additional 100 hp at the wheels. if your wallet isnt burning after that you can look into increasing t/b size plenums fueling etc. theres no one mod that doesnt have an effect on the entire car

 

You will eventually have to make a choice.. Legit power adders, like a tune and/or an exhaust.

Any intake mod or maxi-turbo-flo-master-blaster-intake filter will NOT give you any power with a STOCK ECU or 1bar tune. Why>>because you have limiters built in the mapping. If you slapped a belt driven supercharger on your engine you would NOT make over the rated power output of this engine. You would make more torque due the forced induction.

On a side note: If you are overboosting, you need to trace the control lines from the N75 frequency valve to each turbocharger actuator. You will also need to pressurize the actuators and watch the wastegate linkage "movement"

 

Like Kevin said, sort out your over/under boosting issue before you do any mods.

 

Great info.

Yes, I had intended that it was going to be my N75 valves. I will do a pressure check at the same time, but based on the way it is acting, I am making an assumption that the N75's are bad.

That is what started me down this path because I figured I would need to do a partial drop on the motor to get at the N75's, so figured I would add the IPD at the same time, but that said, I will not after your advice.

Thanks
Ed

 

Ed, you do not need to drop the engine for a N75 replacement.

It is more important to pressure test your wastegate actuator>> jacking the car up will be required for this test (as you know)...

 

I have the 74MM IPD with the 997 TB.

As others stated without other supporting mods I doubt you will see any improvement other than a lighter wallet.

I did mine because I had a leaking #16 valve and my stock plenum cracked upon replacement so I figured why spend $400-$500 on another stock plastic one that will be prone to crack versus $900-$1000 for the IPD and 997TB.

Sam @ ByDesign tuned my car with the 74MMTB and other supporting mods and versus the stock TB it seems like the car has more power off boost and that boost build sooner.

This is a very hotly contested upgrade because of the "+35 HP" number. If you look at the dyno chart all it does is move the graph to the right so that you are getting more power sooner but overall peak vs peak is mostly the same.


Also, this is a PITA to install. Took me 8-9 hours including doing all check valves and pressure testing.

 

The actuator itself ? I was going to test for a crack in the lines to make sure they are holding pressure.

I will, however, I am thinking they are good. I should start from the beginning. I had posted something about this in the fall.

When I started having trouble it was because my car was boost limiting at .4 bar. I actually thought it had something to do with my stuck fuel gauge. Every once in a while my fuel gage would get stuck on empty if I ran the tank down too far. Then, I would also see this .4 bar limiting. But, no issue with the gauge and still .4 bar.

Talking to a tech, he recommended that I disconnect the battery for a few hours, then reconnect and turn the car on without starting for 5 minutes, then drive and see what happens.

Well, no more .4 bar limit, but now it is just as likely to go up to 1.1bar.

So, because I had the car limiting at .4 bar forever I am thinking that the actuators are doing there job. Just not getting the right information from the N75 valves.

Thanks

Ed

 

Boosting .4 bar means the car is in a failsafe mode as something is not right. The n75 itself could be bad. It's very easy to replace. No need to drop anything.


Regarding the fuel gauge issue, if you let the car run down low and only fill it up a little the gauge won't register and it will not move. This is stated in the manual.

 

as others have said, you can r&r the n75 in a few minutes. you'll see it staring you in the face well before the couple of hours spent getting at the plenum ( easy ) and replacing it with an ipd ( not so easy lol )

but hopefully *we* have all dissuaded you from messing with any plenum ( for now anyway..) unless like nbressete mentions he found, you have a cracked piece of plenum/plastic. then of course why not IPD. it's seemingly well made and not plastic and worth the 800 +/-.

also, as other have noted.. if you are boosting NOW to 1.1 on a stock k16? then as kevin notes you probably have simple wastegate adjustment issues. this is very common and often the source of overboosting. even moreso ( in my limited experience..) than the n75 going bad. although that little part is cheap and also known to fail. but i'd go with a wg adjustment well before i began throwing parts. even a simple n75 valve. it's not out of the realm of possibilities either that you have some serious boost leaks as well.

limp mode of .4 though is not ( or never seen/heard?) a wg adjustment so the n75 can't be ruled out but you're "close" i can feel it lol. good luck w it.

oh yeah, one other point... forget about the gas gauge and its purely coincidental "acting up" during these quirks of boost. a coincidence as the gauge is electronic for half its measuring capabilities and therefore is "guessing/estimating" lol. it doesn't "like" to be under a 1/2 tank.

 

I wouldn't do the IPD without the 74mm TB. I went this route and am very happy with it. However, the best advice is to take all the brass fittings out and Teflon tape them back in.

 

Don't be scared about another 100 hp on this motor... regardless of the miles.