Series II (Supercharged) Engine Modifications

This thread is for collecting info on mods that have been shown to produce real results on Series II SC Rivieras. It can be used as a reference for those looking to mod their engines.

New members: before attempting these mods, please read Modding 101.

Contributers: If you've done something to your Series II SC engine, whether it be home-made or aftermarket, please post the name of your mod, an image, how much it costs, the perceived benefit, and a link to more info if possible. One post per mod, please, keep it short, and only report mods that others haven't already posted.

If you want to post a mod that's similar to one already posted (ex: same item, different brand), please explain why it is different or special compared to the previous. If you have extra info about a mod that's already been posted, please post the info; it will be merged into the appropriate post.

Remember, members who look at this may or may not understand the dangers of adding increased boost. Please include a warning if your mod could endanger someone's pistons!

I'll start it off...

INTENSE MPS (Modular Pulley System) for Supercharger



Price: $99.99

Noticed significantly increased power, mainly lots of low-end torque, with the 3.4" pulley size. Also have 3.3", 3.2", and 3.1" sizes, each step down resulting in more boost and a few extra HP. Pulleys swap in 5 mins. Pulleys sized in .1" increments, stock 3.8" size available.

WARNING: Undersized blower pulleys create extra boost. Please research before doing this upgrade. Scanning and supporting mods recommended.

More info:

http://intense-racing.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=IR&Product_Code=IMH-090&Category_Code=BE

FAQ:

https://rivperformance.editboard.com/series-ii-engine-transmission-f4/what-are-the-pros-cons-of-dropping-sc-pulley-size-t32.htm#36

wow..nice AA

ZZP 3" shorty down pipe

Price:$90+S&H

Used to reduce some of the pressure built up in our stock double walled restrictive down pipe. lowers KR.

ZZP's product has excellent welds, interlock flex, and quality steel.

This mod will not result in loss of low end torque, but it will help your engine run safer if you decide to add more boost.

Estimated HP: 3-10 depending on other mods.
the power added is felt at higher RPM (4k+) and when gaining speed after 60mph.

this item will need to be welded to make it work on a Riviera! also note: the 96's use a slightly different upper gasket at the collector, so use of the stock gasket may result in a small exhaust leak. use dough nut style for replacement.

I have had it for almost a year and i have not had any problems with it, nor have I heard of someone regretting buying it.(unless they decide to move on to headers)

Removing the catalytic converter is illegal in ALL states! many states do emission testing so please check your local laws before tampering with the exhaust. That said, the DP sits too far back to weld directly up to the stock cat. it is 10x easier to weld in a 3" straight pipe in place of the cat than it is to cut out the cat, cut off a piece of it, and re-weld it in. Removing the cat will only yield minimal gains in HP.

LINK

Sorry, this is the only pic i have of it installed:



Comment by TonySmooth89: To solve the flange problem , i had them weld the pipe onto the flange section and cut the pipe to fit up to the converter. I'd say it was noticeable up above 3500rpm... keeps the engine from leveling out so much as it climps in rpms... cost me 90 for the pipe and 60 for the labor. for 7-10hp its worth it IMO. And i'll see how the plog helps too.

Stage 2 extreme gutted airbox!!!

Ok so thats a bit of an overstatement, but what i did was i took the baffling out like everyone else in the airbox , and then i noticed while looking at it that parts of it that hold the baffling blocks the hole in the fenderwell , so i took out the bottom of the box and i cut it out to match the hole in the fenderwell. It seemed to breathe a bit better IMO, but even if it adds 1 hp over a standard gutting its still worth it as its free and takes about 5 minutes. I know others have taken this a step further and expanded the hole in the fenderwell and the box even more, but for those who want to keep a factory look or dont want to cut up their fender/ cant afford a custom intake , this is a pretty good mod.

I will try to take pictures tommorow.

A step further - Fender Well Intake



You can rarely go wrong with a fender well cold air intake. It's one of very few power modifications that gives you practically no undesired side effects at all. More top end power, no loss in fuel economy, beautiful blower whine sound (unless you don't like that), generally no added weight, can be done for dirt cheap

In my opinion, this should be number 1 for performance modifications.

Gen V M90 swap

Requires many other supporting mods, ie headers, FWI, TB adapter, TB, Maf, programming, cam/rockers, springs, alternator shaving etc. Trans build up prior to install is recommended. This is not a mod for someone starting out and taking mods slow.

Aluminum frame lower intake gaskets

Good for all S2 3800 applications. Removes the problmatic plastic framed LIM's that tend to distort and possibly leak coolant into the oil or cylinders.



Found only at GM dealers or Intense/ZZP/WBS. Approximate cost $50

Comment by Jason: write-up link in billboost's LIM gasket post
http://www.clubgp.com/newforum/tm.asp?m=3764153

Comment by 1998 Riv: GM list is $62.02, unless you can get a discount. I usually get 25% off, but today the dealer faxed me a quote at full retail. Looks like I'll have to mention gmpartsdirect again, at 40% off...

LIM air temp sensor

Early 90's GM TBI motors aka 5.7's had an air temp and water temp sensor used in the lower intake. Approximately ~$14 from any parts store, this sensor can be wired to an Aeroforce or other temp gauge similar to the IAT sensor for an after charger air temp.



Comment by dreww: i had heard about this but never seen a picture of where to put the sensor. Very cool. I was thinking about doing it when I do my intake gasket, but I got enough gauges already. Would be nice to see before and after intake temps with a ported SC though.

High-Ratio (1.8:1 or 1.9:1) Roller Rocker Arms



Price: $299.99-399.99

Noticed a significant power increase in the upper RPMs with INTENSE 1.9:1 roller rockers. This ratio lifts the intake/exhaust valves about 20% more for increased air flow through the engine. Installation not too difficult for amateur mechanics.

NOTE: 1.9:1 ratio should use upgraded valve springs for high-RPM operation. Oil-restricted push rods recommended. 1.8:1 ratio safe to use with OEM springs, offering a lesser amount of valve lift. Installing valve springs increases the difficulty level of install.

More info:

http://intense-racing.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=IR&Product_Code=3800-YTRR-yyy&Category_Code=HCV

http://www.zzperformance.com/grand_prix/products1.php?id=426&catid=104

Write-up:

https://rivperformance.editboard.com/series-ii-engine-transmission-f4/write-up-installing-rockers-valve-springs-push-rods-t9.htm