performance upgrades for my '04 SRX V8

[tjm183]

Hello Everyone

I’m new to the forum and would like all the input and feedback I can get on recommended performance upgrades for my ’04 SRX V8 AWD. I’m interested in a cold air intake and would like any feedback from anyone who has purchased one, i.e. did it make any difference in fuel savings (MPG), did it increase power (HP), and did you install it yourself. I’m also open to other performance modification suggestions. I would like to get the most for my dollar. Has anyone installed a power programmer or this performance chip advertised on ebay for about $25? Here is the link for chip http://cgi.ebay.com/ebaymotors/1-PER...5fTruckQ5fPart
Regards,
Tom

[TTopJohn]

First off, don't buy any $25 eBay "power programmer" or "chip". These are bunk, at best they are wiring harnesses that trick the engine computer into thinking the intake air temperature is colder than it really is with the idea that the computer will then run more aggressive air/fuel/timing maps. As you may have deduced, this is a riskly proposition.

We've got pretty limited aftermarket support. There are a few cold air intake/cone filter intake kits, the Corsa rear section exhaust, and a couple of folks who do custom engine computer tuning (though different year ranges use different PCMs, and this affects whether a certain type of programming software works or not). "Wait4me" is an occasional poster here that does PCM programming as a business, and a forum member has had his Northstar DTS tuned by http://www.blackbearperformance.com/ though that doesn't necessarily mean they can tune the PCM in your SRX. Beyond that, you are in uncharted territory - not that further mods aren't possible, but you and your chosen high performance shop will be inventing things as you go along.

Personally, I'm going to do something to the air intake, then maybe some PCM tuning if one of the well reviewed local GM oriented shops can take a crack at a performance dyno tune. The stock airbox though it does suck air from a nice cold location, seems way too small and restrictive given the size and horsepower rating of the Northstar. Exhaust I'm not going to touch given the wagon bodystyle that can lead to resonance and the fact that it's my wife's car.

Note that the SRX uses a different Northstar than the front wheel drive Cadillacs. Our Northstar is shared with the XLR and the recent rwd STS. So don't assume that just because a part is for a Northstar, that it will work on your SRX - the older Northstar that has been around since 1993 has a few more parts available for it - mostly from folks that swap them into Fieros, dune buggies, street rods etc...

[tjm183]

Hello TopJohn

I’m extremely grateful for the reply. I definitely agree with you on those “performance chips” they probably do more harm then good.

I’m leaning towards the Volant Cold Air Intake and I thought the exhaust went hand-in-hand. I thought more air in requires more air out. I could not find any other cold air intakes, any other companies? I’m open to all suggestions. Would you mind if I sent you a PM? I would like to ask a few questions.

Regards,

TJM

[J. Williams]

Hi All, I own a '04 V-8 SRX too. 50k miles. I'd like to do the Volant CAI too along with the Corsair exhaust. Too bad no one seems to make a supercharger for our SRXs. Or am I just missing that? Not really interested in better brakes, unless I was tracking the SRX, lol. Has anyone tried the Eibach lowering springs or aftermarket shocks? My other car is an '09 Nissan GT-R. Thanks, John

[robhersch]

Originally Posted by J. Williams

Hi All, I own a '04 V-8 SRX too. 50k miles. I'd like to do the Volant CAI too along with the Corsair exhaust. Too bad no one seems to make a supercharger for our SRXs...... Thanks, John

Suggest that you really check the engine capability before attempting to install a supercharger. We believe that Cad has a supercharger for the N*V8, BUT NOT THE SRX 4.6 L!! We have heard that Cad reduced the displacement of the XLR N*V8 to 4.4 L in order to increase the cylinder wall thickness ??/ head gasket area ?? / and ???? to accommodate the increased compression due to the XLR supercharger. Maybe you could do a swap for an XLR engine (probably need the whole system w/ computers, etc). Also recommend that you carefully examine an XLR closely to analyze what all is involved.
Good luck !!

[V-Eight]

Originally Posted by robhersch

Suggest that you really check the engine capability before attempting to install a supercharger. We believe that Cad has a supercharger for the N*V8, BUT NOT THE SRX 4.6 L!! We have heard that Cad reduced the displacement of the XLR N*V8 to 4.4 L in order to increase the cylinder wall thickness ??/ head gasket area ?? / and ???? to accommodate the increased compression due to the XLR supercharger.!!

Correct, the same thing was done with the STS and its V variant

[b4z]

It sucks that there is hardly any aftermarket support for either the SRX or it's 2 engine variants.
And the 3.6L came out in June 2003 and there is still almost nothing for it.

[conedoctor]

Originally Posted by J. Williams

Hi All, I own a '04 V-8 SRX too. 50k miles. I'd like to do the Volant CAI too along with the Corsair exhaust. Too bad no one seems to make a supercharger for our SRXs. Or am I just missing that? Not really interested in better brakes, unless I was tracking the SRX, lol. Has anyone tried the Eibach lowering springs or aftermarket shocks? My other car is an '09 Nissan GT-R. Thanks, John

I would just leave it NA stick to bolt ons and keep it sort of relieable, and at least you can launch the SRX

[TTopJohn]

Originally Posted by tjm183

I’m leaning towards the Volant Cold Air Intake and I thought the exhaust went hand-in-hand. I thought more air in requires more air out. I could not find any other cold air intakes, any other companies? I’m open to all suggestions. Would you mind if I sent you a PM? I would like to ask a few questions.

Regards,

TJM

You are correct that the general rule is more air in requires more air out. However, this varies from vehicle to vehicle. For instance, some cars in factory stock form, have more restrictions on the intake side than they do on the exhaust side. On vehicles such as this, reducing the intake restrictions can work quite nicely even if the exhaust is not touched. For another example, say a car has a restritive air intake, a very free flowing exhaust from the cat back, and so so flowing exaust from the manifolds to the cats. In that case, you might see big gains from an air intake mod, small gains from a cat back exhaust, and the biggest gains from combining those two mods with a set of long tube headers.

Hard to say exactly how the SRX responds to mods without some trial and error, but you can see by looking that the exhaust system is already a fairly nice setup from the factory. And you can see that we've got a very small air filter compared to other Cadillacs with similar Northstars and compared aftermarket cone filters. That combined with my self imposed noise constraints for this car means I am unlikely to touch the exhaust, despite possible power gains.

I don't have a link handy but I saw another brand of air intake kit (other than Volant) for the SRX on eBay perhaps it was AFE? Wait4me (that's his username, and maybe also the name of his performance part/tuning company) was posting here a few months ago offering to build a small run of an air intake of his own design that looked pretty good. Then there's always the homebrew option - PVC pipe from Home Depot or DIY intake piping from Auto Zone combined with the filter of your choice.