Intake Manifold Options?

[SilentShout]

Greetings All.

Ive been looking around at some options for the Inlet manifold for the z18xe as the factory one seems incredibly restrictive.

Im leaning towards an NA build on the SRI currently as its different to the turbo palava im used to.

What are the various options and setups anyone has come across on both the C and the astras with the same engines?

Before we proceed Ill point out the obvious elephant in the room being the $1000 euro Flowtec manifold (hate to see what price + postage converted to AU would be)

Theres always ITB's but im guessing with the fly by wire system it would be a massive hassle, not to mention most likely illegal and requiring a standalone ecu for minimal gains over a well designed Inlet manifold.

lastly ive read around the interwebs of a Flowtec copy for a fraction of the price, but seeing as all the threads are old and theres no trace of said manifold on ebay or anywhere, these are not being made anymore.

what have you guys seen around?

Warning: This is an Old Thread This discussion is older than 120 days. information contained in it may no longer be current . Please think of the children before resurrecting this ancient thread!

[chris_r]

The Flowtec copies aren't being made any more. The guy that used to make them also makes the knock-off Mantzel Powerbox style intakes which are used on the Corsa B GSi C16/X16 engines.

Also, from various sources on the interwebz, the dBilas manifold is a massive waste of money, particularly on a standard engine. If you're turbocharging the Z18, then the manifold starts to become worth it.

[DRMAT]

Haven't found anything useful at all in extensive searching of Europe, UK, South America and South Africa... beyond the stupidly over-priced items you already mentioned. ITB's, while hella cool, get very expensive very quickly even before you consider how you're going to control them. The conclusion i've come to after looking at extractors, inlet manifolds, cams, intakes, ECU remaps etc is that the Z18XE is about the worst engine you could ever pick to modify... in Australia anyway. There just isn't anything cost effective out there.

[SilentShout]

Haha wonder how feesable a v6 conversion is, the 2.2 and the z20let are bs expensive.

Prehaps a different engine? Sr20 anyone?

[SilentShout]

haha after some googling aparrently a few people have put v6's in these cars but it looks messy, not to mention most likely illegal on the roads of queensland.
@chris_r what makes it a waste of money for an NA engine??

Blood and soul of my first unborn child... oh sorry i meant price aside, do they not make a difference?

iirc the basic principle of mods for na is not nessesarily "adding" power, just freeing up power thats restricted by the engine and its bits from the factory.


I laugh when people say things like "my 4-2-1 headders added so much power"

Nah mate they made the engine breathe easier freeing up power

[chris_r]

I say that because I have heard and read cases a while back saying the gains weren't what dBilas claim and there's been the odd case where power has been lost. Not something you want to hear when you're spending a fortune on a fancy chunk of metal.

Sure, if you're doing a full NA build like @andrew, the chances of seeing noticeable gains are greater, but just don't go chucking one of these manifolds on a stock engine and thinking it'll be a huge improvement over the stock manifold. On the Z18, I believe the stock manifold isn't as bad as you think it is.

In terms of being different in regards to engine swaps, here's one: Saab B204 or B234. Bolts up to a F23 box too apparently.

[andrew]

a good NA build is not cheap so far I have spent $6k on the top part of the motor so far, the biggest gain you get from the dbilas manifold is that they rise the rev redline from 6500rpm to 7200rpm, the manifold is just prep for work later on or maybe a turbo,
with my manifold the cost was $1800 to my door with cams as well, also I have done a lot of head work too and made a custom fuel rail with bigger injectors on it too
now I am getting rid of my one big coil pack and going to 4 msd coil packs with custom leads made up also looking into doing a fuel surge tank too, its never ending I just keep wanting to more and more,

[SilentShout]

Ive seen a few other people going down the 4 coil with leads route, I assume thats where you enter standalone management territory ??

and in your opinion is the factory inlet manifold as restrictive as everyone says it is?

[Raisin]

I have been playing around with the idea of an NA build on my Corsa too lately as I think it would be a lot of fun on the track. But at the same time, the more and more I look into it the more I'm wondering if I'm just better off going the Honda Civic route for the track car, especially when I don't need to drive it all the time. I mean, I don't want to make big power, but I would like if I could get an extra 30-50kw out of the engine for track use. However, with a Civic, swapping in a K24 puts you square in that power range and if you have an EG the suspension setup offers a lot more in terms of track car setups. I'm not a Honda guy though so I don't know quite how expensive a K24 swap would end up on a Civic.

I think if you have the money to play around with, doing a Z18XE isn't a bad option if only because there's no shortage of them around thanks to all the Astras with them. So if you plan to throw money at an engine and pop a few along the way a Z18XE is probably one of the easier engines to replace for what it is.

[andrew]

yes standalone is what I am doing, I have a haltech ps1000 at the moment still brand new in the box but soon I am upgrading to the haltech elite ecu
which changes everything, for stock or small build motors the factory inlet is fine you wont be losing anything with it,