Supercharging the 2.7 - Opinions

[aussieboxy]

I know there have been many that have supercharged theri 2.5 with favourable results, but what about the 2.7

I understand that the 2.7 has a higher compression ratio. If using the same 2.5 kit what would be the implications of putting it on a 2.7?

Your comments would be appreciated.

Thanks

[rick3000]

I don't think you could put a 2.5L kit on a 2.7L, they make a seperate supercharger kit for the 2.7L engine.

[der Geist]

I talked to the guys at TPC once and one of them told me that the 2.5 kit used a couple of different tubes. They said they could fabricate a 2.7 kit but it would take quite a bit of time. Apparently the 2.7 kit is something they made in a very limited production run. Maybe if there was enough interest they would do another run. I think at the time that they were making kits for the Boxster the majority of people interested owned cars with 2.5 liter motors. Other than the 3 (I think) tubes that were different I think the kit is identical. I am pretty sure that someone who knows their way around superchargers could make it work. The 2.5's compression ratio is 11.0:1 vs the 2.7's 11.3:1 according to the many sources on the internet.

[blinkwatt]

Originally Posted by der Geist

The 2.5's compression ratio is 11.0:1 vs the 2.7's 11.3:1 according to the many sources on the internet.

Let me make sure I'm getting this right. For every 11 units of space in the combustion chamber there is 1 unit left at it's full compression the moment it combustion(relating back to your 2.5L 11.0:1 ratio above)?

[der Geist]

The ratio is calculated by the following formula:

, where

b = cylinder bore (diameter)

s = piston stroke length

V_c = volume of the combustion chamber (including head gasket). This is the minimum volume of the space into which the fuel and air is compressed, prior to ignition. Because of the complex shape of this space, it usually is measured directly rather than calculated.

Ahh...I just couldn't resist that.

Yes, Blinkwatt-you are correct. Higher compression-more HP. Here is the Wikipedia link for anyone who is just dying to know all about compression ratios....

http://en.wikipedia.org/wiki/Compression_ratio

[aussieboxy]

Thanks DR,

I wasn't sure if they were the same kits or not.

[Gary in BR]

From my understanding Imagine Auto modifies the 2.5 kit for the 2.7, I believe the car has to go to their shop and they custom tune the kit.

Ask for Jeremy and tell him Gary sent you.

Gary

[rule1]

Actually it is the 3.2 kit and they said it take a couple of weeks to tune it.

[porsche986spyder]

Any one know the cost? What about the turboworks turbo? Would that be better power wise?

[Adam]

I don't believe turbowerx makes a kit for the 2.7L yet. But after seeing Gary's dyno results I would never supercharge the boxster engine. The gains pale in comparison to the twin turbo setup.

[der Geist]

Originally Posted by Adam

I don't believe turbowerx makes a kit for the 2.7L yet. But after seeing Gary's dyno results I would never supercharge the boxster engine. The gains pale in comparison to the twin turbo setup.

Adam- What were the differences? I didn't see the dyno. Doesn't Gary have the twin turbo? According to Turbowerks they went from a twin to a single turbo setup for the 2.7 liter. He told me they are doing their initial installs on the 2.7 this month. I spoke to him via email and was going to have it done but the logistics of getting it to Austin along with a vacation conflict were a little too much. I had second thoughts as well as I was told this kit would be out "next month" on more than one occasion last year. Also, he told me that the ECU would need extensive reprogramming and I am kind of iffy about that. I am sure the kit is fine but I don't think I want to be the first one to put a turbo on a 11.3:1 compression engine. I would feel a lot safer if the compression was lowered. Maybe that's why the dyno is the way it is. I don't think you can load a lot of boost with that much compression. $ for $ I think a 3.4 swap would have been better. I know turbo technology has moved forward wuite a bit but Turbowerks claim that of the single turbo performing as good or better than the twin didn't make a whole lot of sense to me.

[Adam]

I'm not sure why they have a 2.5L and 3.2L kit already out, but not one for the 2.7L. They said they are going to go single turbo instead of twin? I find that strange since the 3.2L and 2.5L kits use twins. I have never corresponded with the guys at turbowerx so I don't know what all they have to change to make this kit compatible. Turbowerx uses an intercooler and the superchargers do not, so they can boost in a couple more PSI into the engine due to the cooler charge. We are only talking about 6 PSI so even on the high compression engine, it should be fairly reliable I would think. Here's Gary's dyno sheet with base, supercharged, and turbocharges results. He had the S/C on there, but then went to the TT setup. It's easy to see which one gives the best results. Take a look at the torque curve on the turbo!

[blinkwatt]

Damn the powerband on the Twin Turbo is SWEET! It kind of makes the Supercharger set up mild.

[efahl]

Don't forget that the SC numbers were run with the rag in the intake... (I'm assuming that's so until Gary says otherwise).

Eric

[Gary in BR]

I solved the rag in the intake issue. Its actually a funny story...

It was not in the intake during any of these dynos.

What happened after a little investigation...when the car was apart a clean shop towel was placed in the throttle body to keep it clean. All of the people working on the car where not aware the rag was there, and when it came time to put it all back together the towel was found and assumptions began that it was there the whole time.

After a few weeks we where talking about it and the culprit admitted he put it there to keep everything clean. It was an innocent assumption that it had been there the entire time.

As far as the sc kit...
The guys at imagine have always been friendly and professionals. I went to visit the shop for a car show and had them check my install. they went over the car with a fine tooth comb and did far more adjusments then I was charged for. All of the dynoes where done after they made the adjustments.

The dyno results posted are accurate and repeated on two different dynoes.

The reason Imagine said that my result did not match the dynoes they did on the mule Boxster (when I was at their shop I asked for a dyno but because of everyones schedules we could not do the dyno) was that the supercharger needed more air than I was giving it. They said that the there needed to be a fan blowing into the intake, a fan in the front of the car and a fan blowing into the open engine compartment. As you can see from the dyno videos
( www.youtube.com/gwhand ) i only have 1 or 2 fans depending on which dyno session. (the turbo dynoes I did have all been on the same machines as the supercharger dynoes and the same fan setups)

Personally I hate the fact that the supercharger did not dyno on my car as I hoped it would, with the money I have spent I could have done a 3.4 transplant. I would love to see someone else who has the supercharger on their 2.5 and hope my results are just a fluke.

My suggestion is that if you are interested in a power bump on a 2.5 and on a budget find a used supercharger (jaay has one for sale) if you have a middle range budget get the turbo. If your budget is even higher go with the 3.4 upgrade.

I hope this clears up something and probably will start a debate on a few others.

Everyone make it a great weekend, I know I will I got my Zymol and a 6 pack ready.

Gary

Originally Posted by efahl

Don't forget that the SC numbers were run with the rag in the intake... (I'm assuming that's so until Gary says otherwise).

Eric

[der Geist]

That is a pretty impressive increase with the turbo setup. You are right Adam-the tourque curve looks really nice. It looks like it builds power really quickly. I m really surprised about the supercharger though. It must be something with the Imagine's setup. I drove in ohioboxster's and that sure felt like a 300 HP car, I think Randall will back me up on that. He had the TPC kit and it wasn't intercooled but I remember him saying it was putting out about 6 lbs of boost too. Whatever the case I am glad to see such performance increases.

[Gary in BR]

From my understanding the TPC has more power than the other Supercharger Kits on the market.

But TPC dose not market the kit any more, I heard the supplier stopped making that particular supercharger, this was not told to me by TPC its simply what i was told when I was shopping for a sc last year.