M30 ITBS

[528lurker]

I know I will need an adapter plate and modify the thermostat housing, but do I need the ECU from the s38? Also does anybody know about the hp gains from the swap?

[Coldswede]

If your going to spend the time and effort doing this. You really should at least up grade to Motronic 1.3 for it's adaptability.

HP gains will be minimal on the top end but the ITB's will help your lower and mid-range response.

To really reap the benefits of the ITB's you need to add compression, a cam and some headers along with the mentioned better management. ITB's alone add sex appeal but not much Go.

I assume this for a NA engine.

[Frybrid 524td]

Extrudabody ITBs

[Kyle in NO]

Frybrid's suggestion looks pretty legit! A bit pricey, but hey...


http://www.extrudabody.com/servlet/the- ... 535/Detail

[Coldswede]

Frybrid's suggestion looks pretty legit! A bit pricey, but hey...


http://www.extrudabody.com/servlet/the- ... 535/Detail

As I said, "Sexy", but you will still get poor return on your money unless you add Compression, Cam, Headers and Management.

Not to say I don't love the look.

[turbodan]

If your going to spend the time and effort doing this. You really should at least up grade to Motronic 1.3 for it's adaptability.

HP gains will be minimal on the top end but the ITB's will help your lower and mid-range response.

To really reap the benefits of the ITB's you need to add compression, a cam and some headers along with the mentioned better management. ITB's alone add sex appeal but not much Go.

I assume this for a NA engine.

I would actually expect to lose bottom end and midrange with these. You may gain some top end due to the shorter runners but all in all the car will be slower.

[Mike W.]

If your going to spend the time and effort doing this. You really should at least up grade to Motronic 1.3 for it's adaptability.

HP gains will be minimal on the top end but the ITB's will help your lower and mid-range response.

To really reap the benefits of the ITB's you need to add compression, a cam and some headers along with the mentioned better management. ITB's alone add sex appeal but not much Go.

I assume this for a NA engine.

I would actually expect to lose bottom end and midrange with these. You may gain some top end due to the shorter runners but all in all the car will be slower.

Agreed, that would be my guess.

But as engine parts go, they sure are sexy.

[Coldswede]

If your going to spend the time and effort doing this. You really should at least up grade to Motronic 1.3 for it's adaptability.

HP gains will be minimal on the top end but the ITB's will help your lower and mid-range response.

To really reap the benefits of the ITB's you need to add compression, a cam and some headers along with the mentioned better management. ITB's alone add sex appeal but not much Go.

I assume this for a NA engine.

I would actually expect to lose bottom end and midrange with these. You may gain some top end due to the shorter runners but all in all the car will be slower.

Your correct about the top end gain in a modified engine Dan.
In a stock engine the top end is limited by the rest of the hardware so no gains would be likely. Lower down the RPM range where the cam and compression have some "space" left you would notice a small gain due to volumetric efficiency. The gains would be small and hardly worth the time, effort and expense.

[turbodan]

I figure the gains on the top end would be due to shorter intake paths. The stock manifold will restrict top end power due to the length of the runners, which is where ITB's offer gains. Likely even on a stock engine. The gains would be small compared to the power loss though, since they would be above the engines powerband anyway where the cam and head are increasingly less efficient at making power.

At lower RPM you should lose power since the shorter intake paths result in lower air velocity, which hurts cylinder filling. ITB's also don't utilize reflected pressure waves from intake valve closings. That kills midrange power.

[turbodan]

Thats what I've seen with short runner intakes on M20's. The M30 would probably respond similarly.

[Coldswede]

Hmm. OP do it! We need to know the results. Dyno numbers before and after are required.

[528lurker]

Im able to get the itb's for a really good deal, my overall plan was to switch to 1.3 and turbo. I believe if I had itbs, an air box, turbo and a good tune I could run less boost and still make over 300hp. yes this is all pricey but I think very cool and possible better.

[turbodan]

For low boost you're better off with the stock intake. More area under the curve, more torque and more usable power. Up to a certain point it works well. Once you start making more torque than you can put to the ground, then the short runner type intake starts to make sense. That way you can trade off some of the brutal midrange power for more usable top end power.

[mooseheadm5]

Im able to get the itb's for a really good deal,

Buy them and sell them to fund the other stuff.