excuse me if this has been asked before, but i did a search and couldnt really come up with a valid answer. soooo....

im thinking about buying a 86' Firebird with the 2.8L V6/auto trans combo. im thinking about throwing a few parts at the car and was wondering how they respond to some basic mods. to anyone who has done some modding to these cars id like to hear your results, dyno numbers and track times would be awesome

what do these things run in stock form?

what can i expect from bolton mods like full exhaust, gears, intake mods, tires, stall, and suspention?

finally, heads/cam/intake manifold mods? maybe even nitrous?

thanks in advance guys

 

go to the v6 section and look at the threads..one tells how to install a turbo..one has after market parts..

stock wise they run pretty good..mine is stock right now just a cold air intake on it

 

Dave has done extremely well with his 2.8/3.1 builds. I'm sure he'll chime in soon, so he'll comment on his old naturally aspirated setup, but I met him a few years back when he started fooling around with turbo chargers. Here are some clips, one of the new setup, and the second of the results. Mind you, he recently swapped one of our member's for a larger turbo, and dyno numbers will hopefully be here on March 14th, as well as new track times....;

http://www.youtube.com/watch?v=LuaInKgvqsA

http://www.youtube.com/watch?v=KALeK3Rlcys

 

Stock you'll get 16-17's. Not great, but still about as bad as a tbi 305. With exhaust, suspension tweaks and gears you'll see 15's, and you could probably manage 14's- maybe touch 13's with a built iron head motor & lightening. The sky's the limit with aluminum fwd heads & forced induction. Where you'll end up is really unexplored territory, these motors haven't really been exploited all that much. There's 13 sec n/a fwd cars running around with these motors, however longterm durability is still questionable with early blocks. Circletrack racers have split the lifter valley after many seasons, but fwd blocks and the 3.4 rwd block shouldn't have the same problem.

 

thanks for the responses

i wasnt really looking for info on turboed cars, as thats not the route i wanted to go. what id like to do is boltons, then spray, and finally heads/cam. seems like most members who delve into higher modifications usually go turbo tho... the N/A (+ n2o) approach kinda seems like uncharted territory

as for the lifter valley breaking... on circle track cars... i wouldnt think that would be an issue with a dragstrip car. circle track cars, id imagine, run at high rpms for an extended amount of time. a dragstrip car would only be abused for a few seconds during a run (well, somewhere between 12 and 17 seconds)

L03 cars turning 17 sec 1/4 mile times? at high altitude maybe. my bone stock 84' LG4 auto Z28 went 16.0 at 85mph. if i could get a stock 2.8L to do 16s, with 15 less hp and 90 less ftlbs, thatd be damn impressive

anyone else with info? id greatly appreciate it

 

Yep, 7000rpm 300 horses for hours on end. Gives the motor a good beating for quite a while but later blocks have additional reinforcing in the lifter valley. Depending on options (and how beat up the car is) L03 cars can run in the 17 sec zone.

 

A T5 behind a 2.8 is allot more fun

The wicked sick nearly useless under normal driving 1st gear gets the RPMs up fast.

You can either putt around in a 2.8 car or go all out.
If you try to half azz it, you won't get anywhere quick.
Gotta get them rpms up and keep it up there.

 

and...depending on options (and how beat up the car is) LB8 cars can run in the 20 sec zone. Lets compare apples to apples here. the only way to be fair is to judge the performance of both cars at their best. its not fair to put a clapped out V8 with a horrible driver against a well running V6 with Evan Smith behind the wheel and call it a good comparison. the L03 has 35hp and about 90+ ftlbs over the V6. all things being equal, the L03 will win, considerably. but enough of beating a dead horse... no more V8 hating ok?

Gumby, the car im possibly getting will have an auto behind the 2.8, but id eventually swap that out for a stick. i just like driving stick cars better, and im pretty good at rowing gears at the track as well (see car in sig... ive had practice)

heres a question: if i dont add any aftermarket parts, but tweak the car a bit in the form of removing the A/C and emissions equipment, do some weight reduction, some free mods, and add a set of sticky tires, would it still be considered stock?

 

I was just using that turbo 3.1 car as inspiration. Your already familiar with these cars, so your well aware that asking the average LG4, LB9 and LO3 to pull around 3300+ pounds of weight is a little much, let alone for a 2.8. I would honestly start my build from the rear, forward. You'll definitely want to install a posi, and since your going manual, 4.10's for a T56, or 3.73's for a T5 (use an adapter plate, if necessary). Take advantage of that aluminum driveshaft from a fourth gen, too. These little V6's love to rev, so it's the same principle with any engine build and camshaft selection, symmetry, depending on where you want that power be. Aside from the cam, personally, I would look into an entirely diffent upper end, 3400 cylinder heads, 3500 intake setup....

 

if u want to stay n/a do cam + gears, then headers, catback.

on a stock 2.8 with iron heads cam and gears will net u the biggest gains besdied porting the heads

stall converter works pretty nice as well u have 2 options converter out of an s10 pipckup but they are weak,or a tci ssf unit which ships with a 3k stall which is over kill for a pretty much stock motor

 

while i am familiar with the V8 versions of these cars, im not sure exactly what to expect out of the 2.8 variant. the car WILL be drag tested (and maybe even dynoed) and i was looking for a baseline to get a feel for where i should be at

are these cams flat tappet or roller?

ive had lots of good luck with Comp stuff in the past, so id probably go with them over another brand. i did some light searching and it doesnt look like they offer much... looks like the biggest grind is 212/212 with lift in the mid .400s with a 110lsa... seems like old tech to me though. too bad they dont offer cams for these motors with better lobe technology, something like the current XFI line would be awesome. i was kinda hoping someone offered a split duration cam with lift in the lower .500 range, perhaps id have to expand my search outside of Comp Cams

for now the car will remain auto, but a stick will definately be swapped in later on down the line. ive dealt with the S10 stall before, and agree its weak. i also agree a 3000 stall on even a mildly cammed V6 is probably overkill... not to mention expensive (probably as much as the cost to swap a manual trans in)

one more question... how is the 3400/3500 top end stuff to swap in? are we talking direct bolt in replacement for the 2.8 hardware (besides the obvious PROM tune)? am i limited to a certain valve size due to the 2.8s smaller pistons than the 3.4/3.5 (kinda like how 305s can't utilize 2.02/1.60 valve cylinder heads due to its 3.75" bore)?

thanks for all the input guys, good stuff

 

The heads and intake are in fact bolt in, but I believe you will need to clearance and/or modify the intake a tad to allow for the distributor to seat properly. Yes, much like the anemic 305's non usage of the 2.02 heads, the 3500 cylinder heads will not clear the 2.8/3.1's tiny bore. Stock prom's (w/MAF's) are good for up to 9 pounds of boost, so the additional air from your NA setup won't be a problem....

 

In all stock form if you get the temps to stay under 200f and get both the intake and exhaust flowing free you won't be disapointed.

 

When I first had mine it was all stock, it was fun to drive until it warmed up.

By time Id get half way home from work the temp would be normal for stock but its got sluggish and unresponsive.

Only cooling mods I did was an aluminum air dam, made a true ram air cold air system. And removed the AC rad. Now I don't even need a fan, it never comes on unless I sit still for a bit.

But that was enough to make it run crisp and responsive all that time.

With the ram air system came a super low restriction air filter, no cat and a free flowing exhaust; it will rev fast and hard to and beyond redline. [Still pulling hard after red. ]

Now after some time I changed to a side pipe exhaust and the simple tunr out and the end of the side pipe was to much, I lost allot of power up to.
Just didn't rev out as fast. Knocked a hole in the end of that bend and back to normal.
[You don't even want the loop that goes over the rear axle.]


For allot of folks their experience in a V6 3rd gen sucked and it will in all stock form, once it get up to stock temp 220-240 it turns into a slug.

 

delta cams does a very nice 260 grind cam its avery good all around ca, cam will run u 50 bucks and 50 bucks for lifters. for a 100 bucks they will grind u any spec cam u want pretty much.iron heads its pointless to go over .520 lift

head swap will also require a piston swap and a swap to dis 3500 heads will not fit the 2.8/3.1 bore so u will be limited to the 3400 stuff if staying n/a head swap is def the way to go

the v6 s10 converter will stall about 2500 and works nice on an n/a motor but once u start to make some decent power u will break it

the tci unit runs about 4-500 bucks very nice unit if u want to go that way and they may even be able to tighten it up a bit before they ship it out to u

 

.... your making it sound more than it really is though lol. Why couldn't he swap to a set of 3.4 heads and intake out of an F-Body, and trigger the DIS with the stock ECM, don't they share the same exact signal?

Limited to 3400 stuff lol? Why couldn't he run the 3500 UIM w/the 3400 LIM....?

 

dis requires an external crank trigger on 2.8/3.1 blocks, im pretty sure the 3400 uim was better then the 3500 one stock.
dont thing the maf ecm will trigger dis as well,would have to do a ecm/harness swap and do some repining on the harness

or go standalone system fast/acell dfi / megasquirt

 

Hold on now, I was never beating up on v8's. I'm not biased twoards v6's or v8's, both have merits that get overlooked. But in all honesty I've driven and smoked a few L03 cars with my 'lil v6. My buddy has a ragtop that's an absolute turkey with irritating highway gears. Stomp on it and all you think is 'This is a v8? MOVE damn it!'

You can't use 3500 heads on a 2.8/3.1 block because the combustion chamber will overlap the cylinder- or so I've heard. Firstfirebird did some trial fitting and said it was no-go.

A maf ecm can run dis using a 3100/3400 coil pack. Generates the same signal as the distributor and has the same 10* base timing as the distributor versions do, just need a crank sensor and proper rewiring. Someone on here is putting together a bolt on crank sensor kit for the 2.8/3.1's, otherwise you need a 3.4 block which had dis provisions from the factory. And a 3x00/ distributor setup isn't very likely unless you're willing to screw around with the manifold alot. The #5 (or #6?) runner overlaps the distributor hole by an inch or so.

Crane cams offers a good selection of cams including a few solid profiles for these motors- but you might want to hurry if you want to get your hands on one. Pretty soon they won't exist at all. Shame really.

 

Buy your crane stuff quick. they were sold to china.
Parts will be full of lead soon

 

i know all about heat soak and how it impacts engine performance. after drag racing numerous L98s, LT1s, LG4s, LB9s, etc over the last decade or so, i NEVER run my cars at the dragstrip hot. when i go to Cecil, i go all out: icing the intake, decreasing the rear tire pressure, pumping up the front tires for less rolling resistance, cooling the engine, stalling the converter... and so on. i plan on extracting the MAX out of each car i run, and this V6 3rdgen will be no exception

first things im going to do to it is reduce some weight, delete the unnecessary options on the car (A/C, AIR, EGR, etc), try different timing settings, skinnies up front with DRs out back, and any other "free" mods i can do to get an accurate baseline of where the 2.8 stands (any help on the "free" mods you guys can give will be appreciated). i plan on having some dyno time as well, as theres a very reputable shop right up the street from me (RPM motorsports in Claymont, DE... home of the first C6Z06 in the 8s). i plan on taking a scientific approach to modding this thing, and will document everything, as it seems theres not much hard info about these engines. im kinda getting excited

sounds like the 3.4/3.5 swap isnt feasable right now, as this car will be my daily driver, and i wont really have too much down time to perform a engine swap. maybe one day if something else replaces this as my DD. for now it seems as though a cam/valvetrain replacement, and some head/intake porting is going to be the limit as far as mods go (maybe some nitrous if im feeling up to it). if i can pull ahead of B2L 3rdgens with the stock displacement motor id be more than happy (without spray)

so... lets here some "free" mods that i could do to tweak the stock motor so i can get a good baseline before i start throwing parts at it

 

Plug the throttle coolant lines off, cut out a hole under the air filter canister to draw cool air, remove as much weight as you can (heat shields, spare/jack, a/c, crash bumpers if you're brave) run a can of seafoam through it (these motors are notorious for carbon buildup), put some F1ZE injectors in (there's a thread called 'Ditch your stock injectors!' about it), replace/remove/destroy crappy stock v6 firebird intake pipe with something better (v6 camaros have the tpi-style air box), There's more 'free/cheap' stuff I can't think of right now. Once you break the motor open get in contact with project89- he's messed with the iron heads alot and can give you some good porting tips. You'll also want to switch to a better ecm for tuning, ether a '730 (stock on '90-'92 v6's) or a '165 ecm (look here) are the best choices. I'm glad to see more interest in acutally racing these engines, I think we're all curious as to how much can be squeezed out of a 'stock' motor.