Notion

Hi all,

Still falling in love with my '04 touring roadster I picked up last week.

As an ex-s2000 owner I'm all too aware of the obsessive need of the sportscar owner to throw dollar after dollar at overpriced bits of metal with designer names promising everything from hp gains to eternal life.

I'm a little longer in the tooth these days and have already decided that I don't want to throw out the balance of my ride chasing too much hp - I'm pretty sure FI isn't for me and I have no need to impress (read deafen and annoy) the ladies with the booming noise from my exhaust pipe

That being said, I would like to tune the car more personally to my needs and would like to try for a reasonable true 10% hp/torque gain and some moderately tighter handling.

I've been researching some engine and air mods with this goal in mind and understand that you can't just add the manufacturer-claimed gains together to get to your actual goal. I also want to plan a solid path so I can add each mod a little at a time - although I'm not even sure if that is the best way to go.

So far I've worked my path out as follows...

1. Unorthodox Racing Underdrive Crank Pulley Ultra S (Claimed +5-12)
2. MotorDyne 5/16" ISO THERMAL PLENUM SPACER (Claimed +11-13)
3. K&N Typhoon Air Intake System (Claimed +10)
4. Kinetix HiFlo Cats (Claimed +5-8)
5. ECU Reflash & Dyno Tune

How close/far do you think I will be from a +27-30whp gain from these mods? Some of these +HP claims seem rather lofty on these mods. Also any info on alternative mods, doing them all together etc etc.

All well informed info from experience gladly appreciated.

Notion

dTor

iTrader: (27)

Thank goodness... we have a well-informed noob who can use the search function!!

WELCOME!!!!

Seriously, glad to see somebody here who knows what they want and how to ask for advice.

As you probably know, a lot of manufacturers claims are based on the worst dyno of a stock/nearly stock setup vs. the best dyno from a well-modified setup that will actually get decent benefits from the particular mod they are testing.

With that being said, you can get an honest 10-15 rwhp just from a tune. If you have access to a wbo2, you'll see that your engine will stop at nothing to keep the afr at 14.7-15.2. Trust me on this - I've been staring at my datalogs and fighting, I mean "tuning", the stock ecu for a week now with a piggyback computer (emanage).

If you don't want to put yourself through the hell I'm going through, you can get an ECU reflash from places like AAM, Technosquare, or... damn, there's another one, too. Search for ecu flash or similar.

Intakes, you're looking at about 2-5 hp, but stay away from CAIs. The consensus is that they actually lose a bit of power due to the reduction in intake air velocity. Mostly, an intake is to get a "better" sound from under the hood.

The plenum spacer is a worthy mod, especially if coupled with the MREV2 from the same company. There is still a bit of debate on whether the combo will result in a lean condition on Revup engines (basically pre-'05 motors), but, as has been stated by the manufacturer, if you aren't already lean, then the combo won't suddenly make it lean. Also, the spacer will give your engine a bit more growl when you romp on the gas a bit. I don't know about the MREV2.

Crank pulley... I have no firsthand experience.

HFCs - I have the kinetix HFCs. I had headers before them, and installed a custom true-dual after them. I'd say they have their place, but I don't believe the cats are a serious choke-point until you've opened up everything else.

Headers - If you can install DIY, or can afford $200-$400 to pay somebody to install them, do it. Better power everywhere, amplifies the stock exhaust note slightly and nicely.

For the bad news - Even with all of the above mods, plus a full exhaust, you're probably only looking at roughly 250-280 rwhp, depending on the shape/baseline of your car now. These engines are tuned very well from the factory and it takes quite a bit of money and effort to squeeze just a few more ponies out of it, especially with bolt-ons. Right now, 300 rwhp n/a is a barrier broken by very few, and they, at a minimum, swapped cams and had headwork also (some have fully built engines).

If I had to rank your list in order of priority, I'd say

Plenum spacer
Intake
Tune
HFCs
pulley

I don't know how pricing is for S2Ks, but I'm sure parts for it are a bit lower comparatively than our parts are. If you're looking for a cool sound, you'll get it. If you're looking to bruise everything you line up with, buy a faster car.

Or you could just buy nitrous and call it a day.

Notion

Thanks for the in-depth reply.

I'd be very happy at achieving 280rwhp with bolt ons and tunes, especially as the stock 04 as I understand it sits around 237rwhp out of the factory.

I was wondering about the combination of the MRev2 with the plenum iso spacer as it seemed like it may be a significant enough breathing option to make a difference that could benefit from a good intake/filter and then a throaty exit path in the shape of the headers. Of course without a reflash I'm sure it will be close to pointless - I have heard that the ECU will pretty much compensate for all of your fta mods rendering them virtually useless.

I wonder how many people are rolling around out there with 5 grand in mods and a stock ECU convinced that they are making solid gains?

It sounds like I should budget to get the whole air section done in one go and then get the ECU flashed and tuned on that setup. Other mods that don't mess with the fta ratio can come in steps (like the pulley).

Sounds like it's time to save for this list as one item...

5/16 Plenum Iso
Wrev2
Popper Intake
Headers (any suggestions welcome)
Hi Flo Cats
ECU flash and dyno tune.

Hrmmmmm, time to start digging in the back of the couch

AParshall04

iTrader: (6)

I would definately recommend the following:

-5/16 plenum iso
-Mrev2
-JWT Popcharger (only like $100, sounds good, proven gains)
-I'd x-out the headers personally, i think it's a waste of money
-I'd add either JWT flywheel and clutch if you want or a 3.9 Final Drive
-I've heard of problems with every hiflo cat company except crawford
-reflash

Personally if money is an issue in all of this, i would take the first 3+JWT clutch/flywheel alone. Of all the mods i had i felt the flywheel the most and rev-matching around turns becomes even more fun.

As far as handling, wheels+tires are key! Some wheels that arent too heavy with somethiing like a 18 or 19 by 8.5 in front and 9.5 out back. And adding a stickier tire like a toyo T1R will make a huge difference as well. The stock wheels and tires suck besides track model.

Just realized you're in SD, if you are looking to buy a popcharger i could bring mine back with me from Sacramento when i go home for thanksgiving.

Acree

iTrader: (29)

As a person who personally installed their own headers, I would tell you to do headers before any other mods of the car. Not even kidding. I absolutely love the power band with my Strup headers and I wouldn't think of going back to stock.

-Acree

Notion

Hi there,

Sounds great yes I am looking to buy one, I assume you have the heat shield with it too??

dTor

iTrader: (27)

+1

A lot of people think that adding an intake and exhaust is the way to start. It really isn't, unless you're just looking for a louder sound, which you said you're not. Once you get most of the other breathing mods do, then you should consider getting a new exhaust. I can't tell you how many threads I've read about people disappointed with the power made, or rather not made, by adding an exhaust on an otherwise stock vehicle.

However, when I added my exhaust, I already had intake, 5/16 spacer, headers, & HFCs. The exhaust really woke all of that up. I did have solid gains with the other mods beforehand, and the exhasut basically uncorked it all.

And no, you will definetely realize a gain without getting a tune. Not as much of a gain, but any of the above you do will be somewhat beneficial. One of the big things a reflash does is change the target afr from 14.7 to, I'd imagine, about 13ish. Therefore, it will benefit your power regardless of the number of mods already done. However, the more mods already installed before the reflash, the better they can fine tune it to your vehicle.

Notion

Great information so far (although some of it is conflicting, but that's the beauty of forums ).

I think the note from the Z already sounds very nice and I'd rather rely on my good looks, great personality and huge ***** to impress the ladies rather than the boom from my exhaust lol

It certainly sounds like the plenum needs to be my first focus closely followed by air in and out.

Notion

Alberto

iTrader: (14)

You will not gain close to 30whp with those mods. NA I ran a Pop-charger, Crawford Plenum, test-pipes, Injen exhaust, UR crank pulley and Techno flash. This netted me 262whp/252ft/lbs on a Dynojet SAE corrected, 23whp over what I did stock on same dyno. Did it make a difference? For me it did, I went from running 13.7 @ 101 to 13.13 @ 107mph with those mods. Hows that for proof...your not listing a cat back, and your wasting time/$$ IMO with hf cats.

myladyz33

iTrader: (2)

If you do decide to get headers don't get any other than Crawford there the best hands down made for our cars

Notion

I'm still learning my mods as I go here so this is all a great help.

I have still have to read up more on flywheel, headers and test pipes to get a feel for what to expect from those. Living in CA I have some pretty tight emissions standards to stick to so I have to stay aware of that also.

Seems that the hiflo cats don't have many fans.

Sounds like I should have some staggered goals to acheive per dollar spent.
If I could get above 260rwhp on my none revup for my first $2k that sounds like a nice bang/buck ratio.

Notion