Thread: Help With Mod Plans

I don't think you would pick up a full second with just a plog/ downpipe and a 3.4 pulley, maybe I'm wrong though. I ran a 14.48 at 1500 ft with a 3.4 with stock manifolds, 3" downpipe, CAI, stock tune on race fuel and every trick I know (icing the SC,no headlight, everything out of the car, running heater on high you name it I done it). Are you scanning for KR? What are your long term goals and how much $ are you willing to invest.

I would at least consider headers in place of the plog & downpipe. I didn't see much difference with them on mine. and I wish I would have just invested in the headers right off, now I'm waiting until next year to pick up a set of ZZPs. Most members on here are happy with the speed daddys and you can't argue with the price, but I'm not going to clearance my firewall to install them.

Also I would be considering either 1.9 rockers if not a cam.

Originally Posted by blueguy

For $500 or less you won't get any better gains than nitrous with a re-tune.

Can't argue with the HP per $ of nitrous for sure. I was curious about long term goals, even nitrous should do better with headers I would think.

I'm more interested in making power I can use legally every day, as opposed to an artificial, temporary boost reserved for the track, which I would have pay to refill after a few dozen uses. I may not reach the goals I want, but I do know what I consider practical. I'm not really interested in NOS, and headers seem like more of a pain than a PLOG, not to mention the additional cost of having it installed (I do not own any sort of welder, nor am I willing to learn on my daily driver). I am leaning toward a PLOG because 1) it is easy enough for me to install, which saves time and money, 2) I've heard of no fitment issues or modifications needed on the current model ZZP sells, and 3) I imagine they don't make the car much louder, and it's important to me that the car be pretty quiet. As a side note, I've also not seen definitive data to suggest any large power difference between a PLOG and headers in a simple 3.5/3.4 setup like I plan to do. I appreciate the input, but I am more interested in advice from people who have gone the route I want to go. 😆

Originally Posted by 0069GTP

Can't argue with the HP per $ of nitrous for sure. I was curious about long term goals, even nitrous should do better with headers I would think.

My long term goals are simply what I plan to do in the next few months. I haven't had good luck modding my car, and I don't really want a very fast GTP. If I decide I want to go faster than say 14.5 in the quarter, I'll start looking at getting a car that was built to go that fast. Reliability is very important for this car; I take it on 300+ mile road trips a couple times a year for example, and can't afford for it to break down.

What type of mods do you have now? I think if you want those goals, 500 bucks probably is not going to do it, unless you spray. I have had my GTP for 11 years and just after hitting 88k started to mod. I to need a reliable car as my GTP is my commuter car I drive approx 140 miles round trip around 3 days a week for my job now, I used to take a train. I started to mod due to rust in my Sways and in the Factory downpipe by the u-bend. My advice, since we are in the same place, is to first make a list over everything that needs to be done to get it right, (meaning running well as Stock) ,then get a scan tool. An monitor for KR, then mod in stages. This way you see the progression and how each mod effects the engine. I personally started with Suspension and brakes, because if you try to go faster you need to stop and handle. Then as I needed to replace parts, ie Exhaust, I went with ones that increased performance, Like the Downpipe, then a cat back, then Plog. I highly recommend you not drop a pulley until you have a good baseline and a car than is running correctly dropping a pulley on a car that ain't right just makes it worse and you want reliable. Get a Scan Tool, and read the post on here Safely Modding your 3800 follow that.

Here I will make it easy from 3800 Forum

"This section is for those looking to go as far as they can for minimal money and to get the best 'bang for the buck':

There is a very simple and straight forward list to obtain approximately 300 crank horsepower (~240whp) and to be able to run high 13 second 1/4 mile times (with minor track prep- in full street trim).

-CAI/FWI, (the most common used is the 4" inlet, 9" long K&N, but many will work), you want as little restriction and as little temperature as possible for the s/c to provide the coolest output. Do not do a 'hot air intake' with the filter in the open engine bay at this mod level. This runs $50-300+ and power gains are minimal, but you will now hear the supercharger scream when you floor it!

-Downpipe, do a 3"- this eliminates the neck down right inside the first bend of the DP, and eliminates the ubend. These things are cheap if you don't need a cat, but even with a cat, they are worth it $80-200

-Plugs (while plugs are useless for an L36, the stock platinum plugs do not work well with modded L67s). For this step either go with Autolite copper 605s (1 step colder than stock) or Autolite copper 104's (2 steps colder than stock). If you don't plan on going further than this list- go with the 605s. Less than $10

-180* thermostat- just another mod that seems to help w/ KR reduction $15

-ZZP Powerlog- basically a front header only- eliminates the neck down point just before the crossover pipe, and is a very quick and easy install ~$100.

-1.9:1 modded stock rockers- open the valves more, letting more air in and out. These are the most difficult part to install of these basic bolt ons, you pull both valve covers to change them- but you can leave the stock springs, and driveability and gas mileage stays about the same. These are the second most noticeable power gain next to the pulley drop. Prices range from $200 used up to about $275 new.

-pcm tuning- you essentially have 2 options here- a canned tune that they send you a new pcm, or driving to someone and having them custom tune it. A canned pcm is far cheaper at $100, but its gains are typically nowhere near a one off tune. Honestly, if you plan to spend the $250+ on a custom tune, you should consider buying your own tuner (they start at $400 for the 3800s)- but be prepared to learn... A LOT.

-supercharger pulley drop (if you will stop modding at this point- go with a press on pulley- if you plan to go on, then buy a modular setup so its easier to change again later)- you do need to scan for knock first- after all those other mods are done. If you still have knock, then you probably have a problem. If not, you're good to drop pulley sizes. With those mods above, you should be good to go for a 3.4" pulley, however, if you had a very hard time getting rid of factory KR, and you barely did- a 3.5" pulley would be a better choice. This is likely the most significant power change for the basic bolt ons, as long as you end up with little to no KR. Press ons go from $20-60, modular setups go from $80-150."

Originally Posted by blueguy

Do not do a hot air intake.

lolololol, k.

Glad that all these other forums hopped on my GP Bible bandwagon after I typed it like six years ago.

http://www.grandprixforums.net/threa...00-Powered-Car!!

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you could go with the water methanol injection kit its safer then nos