This was asked by a member and after a bit of thinking. I think its a great idea top place this in the section.

Also, i wanna thank Bunpin96Monte for all the hard work he did to get this together for all the Members here at MCF.

This originally came from this thread. https://montecarloforum.com/forum/sh...ad.php?t=10942



This is broken up separately into L36 and L67, since they are pretty vastly different, but the main starting point is what is your ultimate goal- and how much do you want to spend?

(more in reply posts since it won't let me start with a long one)

 

L36

Ok, so we'll start off with the naturally aspirated 3800. Before you really get into things, you need to decide how far you want to go. You basically have 5 options to choose from:

-stick NA; this limits you greatly into almost always running equal to or slower than most stock/basic bolt onL67s. Most cammed NA 3800 records are around 200 whp (what a stock L67 makes), with the absolute peak being 247 whp on a fully sponsored car (very heavily modded- good for high 13s in full street trim).The other bad thing about the hardcore setups- is they have very lopey cams with poor driveability and poor gas mileage. This is a great route to go if you plan to do a handful of minor bolt ons and quit, but if you want to go fast, this is not the route to go.

-nitrous; this is effective on any engine, and it works just fine on the 3800s. The upside is huge power for cheap- the downside is obvious: you need abottle to be fast. Therefore, 99% of the time, you'll be stock and slow, and that extra 1% you spray, you'll be fast. Its more of a personal choice than anything- some like it that way. The power limit is how much spray you want to run- no one has ever really tried an all out nitrous NA 3800.

-CSC; I don't believe anyone makes these anymore, so I'll be brief. Power gains tend to come close to that of a turbo, with very high potential due to high efficiency- however you still have parasitic draw through the belt drive system and spinning the blower, so you'll never quite reach turbo potential. People have done 400 whp on stock heads, with the overall record being 495 whp pretty heavily modded- so there is a lot of potential if you can find a kit for cheap. The kits were direct bolt ons.

-turbo; this is where the big power is at. If you are seeking an 11 second or quicker car with well over 400 whp, then this is your option. The kits are pricey up front, but they can make tons of power. All the big 1/4 mile recordshave now been set by turbo cars.There are a good # of cars running ~400 whp on stock heads and a stock cam! There are starting to be some people popping up with 500 whp with heads/cam on the bolt on turbo kits, and the peak now is somewhere around 630 whp. Even a base turbo kit should be able to run 13s/low 14s and beat stock L67s with ease.

-supercharger; there are no true bolt on kits for larger superchargers, although many custom and partial kits have been made for the Whipple 140AX/2300, Kenne Bell Blowzilla 2.3, Magnuson MP112 (similar to what is on the 03-04 Mustang Cobras), and so on. So what I will focus on here is called the L67 top swap. Basically, this includes removing everything from the heads on up on your engine, and swapping them with the stock L67 pieces, including the Eaton M90 supercharger. Here is a list of parts you need:

http://www.wbodystore.com/grandprix/...kit-p-157.html

People have pulled off this swap for under $750 sourcing their own parts off sites such as 3800pro and clubgp classifieds. The only expensive parts are the heads and blower- most of the rest of the parts sell for nearly nothing.

I will say that the top swap is not for everyone, but it is the best bang for the buck outside of nitrous (I prefer a top swap anyways). You start off jumping to over 240 crank horsepower (~200 whp) and 280ish torque- both a nice improvement- plus you unlock all the L67 mods. The current L67 records put many people in the 350-400 whp range (350 whp is doable with stock heads), with a the overall record being ~425whp. The top swap stock will put you in the mid 14s, with fully modded setups going well into the 11s (although a turbo starts to become a better bargain if you're going that far).


Now that you've seen your options on what direction to go, lets look at some generic mod plans:

 

For those wanting to do just basic bolt ons to their L36, this is generally a good start. Keep in mind the records for a stock cam NA L36 is only 177 to 187 whp (stock is about 160 whp), so even with all of these mods, you will still only be in the low 15s.

-CAI/FWI (hot air intakes- where the filter is exposed to hot engine bay air tend to hurt power), $50-300, power gains are fairly minimal.

-rockers (ER ratio rockers are preferred for NA engines), $225-450, and tend to be one of the best bang for the buck mods- especially if you get modded stock rockers. If you plan to go further and get a cam at any time- skip these.

-downpipe (2.5" is preferred for NA, 3" if you plan to go top swapped) $90 no cat/ $180 with cat ++. This takes care of the ubend delete as well. A pretty distant 2nd in bang for the buck compared to rockers. If you plan to get headers down the road, skip this.

-HV3 (intake insert from ZZP), claimed 9 whp peak gain, 30 whp gain at 6000 rpm. This mod does move your powerband up the rpm range, although it is not as noticeable as with the HV2- but it is something to keep in mind. $200+ gasket. Definitely noticeable up top- unfortunately you do lose a little down low.

-Ported Throttle Body, this is getting lower on the bang for buck as far as mods go. They run $180-300+ depending on the level of porting and claim 10 CRANK hp (~3 whp).

-Headers, not really a great bang for the buck unless you get used headers. The only ones reccomended for basic bolt on L36's are the S&S headers due to their smaller size- all the rest of the headers are designed for use with modded L67s, and you will lose bottom end with them. $300++

-PCM tuning, can be a decent gain depending on the company who does the tune- it can vary wildly. Basic 'canned' pcm's they send to you have the least gain (they have to set up on the safe end- but only run $100 and get rid of many annoyances with torque management and also get rid of the top speed limiter. A custom tune, or buying your own tuner (~$400+) is kindof out of the scope of someone doing basic bolt ons to an L36. It would give more power, but you have to consider the cost compared to other options.

-other mods, there are many other mods that gain miniscule power gains that you can consider such as underdrive pulleys, cat back exhaust work, 180* thermostat, and so on- but its up to you how much you want to keep spending for a basic bolt on car.


NOTE: One thing that becomes apparent very quickly is how good a value the L67 top swap becomes when you start adding the above figures. You figure an average of $1000 for it all said and done (and good mechanical ability)- and you are instantly over 200 whp; something the the NA L36 guys need a cam to hit. While some of the basic bolt ons can carry through with the swap- many can't or won't work as well, so its good to evaluate this option early.

NOTE 2: mods you don't need: stock platinum platinum plugs, stock wires, and stock coil packs are all perfectly fine for an L36- none have shown a dyno gain with any of these items. If you do change your mufflers/catback, don't do it for power- do it for what sounds best to you, you won't gain any appreciable amount of power anyways. Lastly, avoid gimmicky electronics such as the throttle position enhancer, trans interceptor, ebay IAT chips, and so on- they don't do any good.

 

If at this point, you chose to go turbo, CSC, or nitrous- you're on your own with where to go. I imagine if you're dropping $3k-4k on a single mod (turbo/csc), then you don't mind spending some time figuring out how to continue on.

If you chose to go with an L67 top swap- then scroll down to the L67 section, but keep in mind that you have higher compression ratio (9.4 vs 8.5)- so you will always be .2 to .3" larger on the supercharger pulley to stay knock free; but now all of your future mods are the same as the L67 guys.


If you chose to stick NA, I can't be of much more help- as NA 3800 builds are extremely rare anymore. These engineshave little displacement, poor flowing heads, and are designed for long term durability and down low torque- so you really need some sort of power adder to see big power. There is a 4.2L stroker kit available now- so you could run high compression on the stroker kit- but you'll still end up getting walked on by the modded boosted guys.

Since you chose to stick NA- the basic premise is the same for most engines- heads/cam is where the power is at- period. The stock NA, stock heads/cam setup record is 187 whp (slower than a stock L67 car at 200 whp)- and it would probably take every bolt on out there, and an aggressivecustom tune to even hit 200 whp. Even then, there are manyNA guys with stock heads and an aftermarket cam that couldn't hit 200 whp. So you really do have to do heads/cam to stand any chance of being competitive.

Here are the top4 NA whp setups so you can get an idea what kind of power you're talking:

-247whp- Intense Stage 3 heads and stage 3 NA cam (sponsored)
-233whp- ZZP GT1 cam and custom ported heads
-209whp- ZZP GT1 cam (unsure of other mods)
-205whp- ZZP GT2 cam, stock heads, PEM's, HV3

One other thing you have to keep in mind, is that on NA 3800s- if you do a cam and heads, you are pushing the powerband higher in the rpm. It is possible for you to do a wild head/cam combo, and run slower because of the lost down low power- thats why many of the bigger cams reccomend a higher stall converter.

Unfortunately, there aren't any good blueprints to make big NA power cheap on the 3800. Most of the guys building big NA setups realized that they were sinking thousands of dollars into setups the could barely keep up with basic bolt on gtp's, and switched over to boosted setups- so if you choose to go hardcore NA, you're going to be on your own to find out what works and what doesn't.

 

L67

(supercharged 3800)
If you have an L67 to start with, you are better off because basic bolt on L67's can easily run high 13s and make 300 crank horsepower with under $1500 in mods.

However, like the L36, you need to come up with a game plan first as far as how far you want to go. Some mods are not compatable, or delete each other (ie rockers + cam, plog/PEMS + headers, etc)- so good planning is the best start. Here are your basic options (obviously you could add a bottle to any of these, so we'll just focus on the power adders):

-sticking with the stock gen 3 m90, is the best way to go for bang for the buck. It is dirt cheap to get it into the 13s and is relatively simple to do. For the big spenders, you'll find that most run out of steam around 400whp, with the record being 425whp. As for 1/4 mile- they've come as low as 11.0 with nitrous, and 11.2 without. At that point, honestly- a turbo is the cheaper option- but its all personal opinion. One option you'll notice as you mod this route is that the L32 (newer version of the L67) comes with the newer gen 5 M90 which is a direct bolt on with the L32 LIM and a new TB- and is along the same lines as the best ported gen 3 M90s in terms of performance and price.

-csc, this is still an option- although now you'd have to get an L36/L26 intake manifold to use it (unless you tried to do a twincharge setup- which is kinda pointless with two s/cs). As far as I know, no one makes a csc kit anymore- so you'll have to get them used. For comparison purposes, the record power is 495whp and the record 1/4 mile is 10.9. It is important to note that there are few csc kits out there, so not many put the time and money into these setups- so there should be more potential given today's resources

-bigger supercharger, in short- there are no true "bolt on" bigger superchargers. The Kenne Bell Blowzilla 2.3L, Whipple 140AX/2300, and Magnuson MP112 (similar to the Eaton M112 on the 03/04 mustang cobra) have been installed- but none are true bolt ons, and all will require a lot of money and custom work if you do find a kit.

-turbo, if you want to go fast- this is your option, period. Turbo's blow away the stock M90 in every way, and have set all the current records for power and speed. If you're shooting for 11s or quicker or 400+ whp, there is no question this is the way to go. If you don't want to go that fast, you need to weigh your options and goals to see if a turbo is a cheaper option or not- generally the faster you want to go, the smarter move a turbo is. Current records for the bolt on kits are 500+whp and high 10 second 1/4 mile slips- so there is alot of potential here.

 

If you choose to go turbo or csc- you're on your own to research from there- I'm not as familiar with those builds. If you're planning to go bigger supercharger and have a kit- you better start doing some research; very few do this, and they are all very roughly sketched out paths- but you will probably have to do custom work.

If however, you chose to stick with the M90- continue below:

Before I begin anything with the L67, there is one thing that you must be very aware of. The L67 is modded around one principle- KR. Knock Retard is the computer's reaction to the engine knocking due to too much timing advance, and too much boost for the mods. Basically, it means the computer is pulling timing to stop the knock, and stop the engine from destroying itself. Many stock L67s have some KR bone stock.

The idea is, to run the car fastest- you want 0 KR all the time. If you are not at 0* KR, then work on your tune more, or do more supporting mods to increase airflow. If you are over 0* KR, then don't go to a smaller supercharger pulley (ie don't increase your boost). If you increase boost and you have KR already, then you will end up with even more KR. If you get too much KR, you will chip the pistons! So the idea with L67 modding is to always keep tabs on knock once you start messing with the supercharger pulley. Either buy a cheap scan tool, buy an aeroforce scan gauge (~$200)- or find a buddy who will let you borrow a scan tool when you swap pullies.

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.


Obviously you can continue adding mods onto that to make more power, but those tend to be the basic core of mods. If you've still got a little knock and want to be safe- a throttle body upgrade is next on the list if you just need 1 more mod.

 

If you plan to keep going with the L67

First off- read through the list above. Ditch the powerlog and downpipe- and go straight to headers. Next, consider ditching the rockers for a cam- depending how far you want to go. As for the pcm- go straight for the tuner or a tune.


The rest of the mods- this is kindof continuing off the above list, going on with what is generally done next- or what is done in replacement of those above. I tried to keep them in the general order that people usually do them. Keep in mind that you need to keep an eye on KR- and drop pulley sizes as you see fit. No one can tell you exactly what pulley size goes with what mods, every car is different- so scan and see for yourself- and generally you shouldn't be dropping more than 0.1" to 0.2" in pulley size with each mod (some people do numerous mods, and then take a bigger drop).

-Headers, these vary wildly and start in the $350- and go up to $1500. Here is a good article on headers:

http://www.wbodystore.com/grandprix/...or-me-a-7.html

Just keep in mind that no 3800 headers fit the 5th gen (95-99) monte carlo. They all take firewall pounding and cutting to fit.

-Throttle body- people have generallygo to the 75mm Northstar throttle body as kits go for $250-400. One thing to keep in mind is the stock supercharger inlet is smaller- and will cause some turbulence withouta ported blower.

-Ported supercharger (or gen 5 M90 swap)- they port the inlet to match your new, bigger throttle body- and the outlet is improved much from the stock casting. This is a pretty good bang for the buck mod starting at about $250-400. Keep in mind not all companies are equal, and outlet porting is a science- so do you research first.

-Intercooler- this is one of the best (albeit more expensive) mods for the L67. Power gains are similar to a cam, but with totally stock driveability. They range from $750-1500 depending which you go with, but you can usually drop a significant amount off your pulley size. The other downside is the complexity of install- you have a plate under the supercharger with hoses coming out- and an electric pump- and this must all be plumbed to a radiator at the front of your car. Generally, install is easier than a cam though.


At this point, you're starting to get really deep- and are probably getting into the grey area with the transmission. You really are on borrowed time from here out- as you are likely close to or in the 12s. Also, you really only have 2 major mods left without looking at all the minor stuff- heads and a cam. This is also the general point where your stock catback exhaust starts really becoming a restriction- so now is a good time to upgrade if you haven't yet. You should also go to the Autolite 103 copper plugs as well.

-fuel injectors- somewhere around the 3.0" pulley, you should start running out of fuel. The 42.5 lb hr injectors should be plenty for most M90 builds- or there are larger available.

-a cam is cheap ~$350, but the install is pretty difficult as you have to install it through the passenger side wheel well. If you plan to stick with stock heads, ZZP's XP cam is designed for that. If you plan to do heads also- then you're open to anything- assuming your lift is ok. Keep in mind that the more aggressive the cam, the worse the idle and driveability is, and generally the worse the gas mileage.

-heads run $800-2200+ (the top end is for ZZP's latest aluminum heads). Install is pretty difficult, but necessary at this point.


I start to get pretty vague towards the end- because that starts to become the point where people realize that they could be going faster with a turbo. Even if you're staying s/c at that point, chances are you've got so much money in the car that you should be pretty knowledgable at that point anyways (or able to do research on your own).

There are many other mods that add tidbits of power here and there, such as an electric water pump, underdrive accessory pullies, and so on- but that is about it for the major engine mods.

 

Common mistakes when modding the 3800:

-Dropping to a smaller supercharger pulley without scanning. Lots of people have done it, and lots of people popped pistons. If you have KR now, it will only be worse with a smaller pulley.

-"Upgrading" the plug wires and coilpacks. The stock wires and coilpacks have been tested fine over 600+ whp, so they are fine for just about anyone. The only reason people do wires is to get more durable ones for frequent plug changes. Few people have found the limit of the stock coils- and its not in power- its rpm. They tend to produce misfires at crazy high rpm (7250+ I think), but practically no one revs that high.

-Thinking the stock bottom end is weak. The stock bottom end is used in the 8.6 second 600+ whp drag car, and many other of our major drag cars, and no one breaks bottom ends with good parts and a good tune. People chip pistons from running KR, but most other failures are flukes. The stock bottom end is plenty for most everyone.


Some links (these are not all, just some of the main ones I can think of). They are in order to some extent with how involved they are with the 3800 community, and how many parts they offer. They are not necessarily in order of best-worst or anything like that.

Please feel free to add more, because I know I'm missing some.


www.zzperformance.com
www.intense-racing.com
www.wbodystore.com
www.pfyc.com
www.3800performance.com
www.thrashercharged.com
www.prjperformance.com
www.hptuners.com
www.digitalhorsepowerinc.com


top 10 1/4 mile:
http://www.3800pro.com/forum/fwdquarter.php

Top cam:
www.clubgp.com/forum search for 'top cam chart' in general, all words, all dates- if this link doesn't work:

http://www.clubgp.com/newforum/tm.as...p;smode=&s=

 

About me: ( Bunpin96Monte )

Just a quicky about me, so you guys understand some of my background- so you all don't think I'm some schmuck who is new to 3800s.

My first car was a 96 monte carlo LS (3100)- I did some very minor mods and was unhappy with the performance, so I started saving for an L67 swap. In the meantime I picked up a 00 Impala LS (3800 NA, L36) as a daily driver/hauler, and shortly after a 99 Grand Prix GTP (3800 SC, L67). Roughly in that time I purchased a totalled 98 GTP for parts for the monte, and began to really get into the 3800 scene- attending some of the events.

I started modding the gtp with basic bolt ons, and I now have almost the exactly basic list as above- and the car feels amazing. Around town, its very tame- just like stock, with equal gas mileage- but once you hit the gas, it'll spin the tires from almost anywhere in 1st, and the thing hauls- it runs 13.9xx. Its a great cruiser.

In the meantime, I fully built the L67 in my apartment- rebuilt bottom end, with forged 9.5:1 pistons. It has zzp S4 heads, an IS3 blower cam w/ 1.7:1 roller rockers, and it had a ported gen 3 m90- and tons of other mods. I swapped the engine in, just like that.

Since then, I picked up a 2.3L/rev Whipple twin screw supercharger, and I'm the process of getting a new intercooler/lower adaptor. We're also working on a new inlet for a 90mm LSx TB. The only other thing I'd still like to do to the engine is a direct port nitrous setup from under the LIM (since I deleted the balance shaft), but we'll see if it ever gets that far. Without that, I'm still shooting for trying to break the highest 3800 supercharged record which is ~530 whp (we're really hoping for about 600 whp with a new cam).

In my spare time, I worked on many various other wbodys and 3800s locally, and at small local meets.

Thats just a little background on me for those who were wondering...