TPIFormula

The name is Travis and Im new to the board, I was wondering if I would make a little more power or see a difference with a set of SLP Intake Runners for my LB9. I was also planning on installing a AFPR on at the same time

Thankyou, Travis

LT1FUN

I'm reading your signature and I'm not seeing anything in regards to your exhaust. Is that because your exhaust is stock?

If that's the case, I'd reccomend you first and foremost pick up a good 3" cat-back. They'll all provide you with roughly the same increase so go whith whatever system sounds best to you. (I'm running Dynomax and I love it)

From there, go with a good set of headers like hooker or MAC. Edelbrocks aren't too popular but they're also a really good header. (despite what others might tell you)

Either of these upgrades will increase your performance way more than a single runner swap, guarenteed.

Look into a freeier flowing catilic converter aswell.

From there I'd move onto the intake. I'd suggest loosing the throttlebody-mounted air filter. I know it looks cool and cleans up the engine compartment but the fact that it's sucking in all the HOT air from inside the engine compartment overshadows any gain you'd get from the fact that there's less restriction in the air path to the throttle body.

Once you've done that then you can start to think about upgradeing the runners.

By themselves, (especially with stock exhaust and/or intake base) you'll see virtualy no improvment at all. Either on the track or "seat of the pants" feeling.

However, once you have the exhaust, runners should be good for around 15HP. Try and save up for an aftermarket intake base aswell since the combination of the intake and runners will net you the biggest increase in performance. I'd say 25-30HP (even more with some tuning)

SLP makes the cheapest runners and they have a lot of material on them so you can hog them out a bit down the road if you want, with a dremel for more air flow.

Having said that, AS&M makes (by far) the best flowing aftermarket runners for our cars. They look stock too. (Whether or not that's a good thing is a matter of opinion).

BBK is also working on a a TPI set up for our car's but don't hold your breath 'cause I've been hearing that for YEARS!!!! (and seen nothing)

As far as the intake base, TPI specialists makes the best base. The downside to this is that both parts are much more expensive then the competition, but hey, you get what you pay for.

Hope this helps

This is the order I'd reccomend you upgrade first.

1. cat-back
2. high flow converter
3. headers

4. cold air induction
5. TPI base
6. TPI runners:

TPIFormula

The Exhaust is mainly stock except new 2.5" pipe from the Y to the tails, as a muffler I'm using a dynomax bullet where the cat used to be.

LT1FUN

Well, 2.5" is a bit on the restrictive side but since it's new, it's kind of hard to justify spending more money on a 3". I guess you can hold off on the cat-back for a while - (atleast untill you've gotton your money's worth out of the old one.

I still say go with header's next cause you'll see twice the performance gain with headers as you would with runners.

Like I said, MAC, edelbrock and Hooker are the best and you can find them for pretty decent price's if you shop around.

I really wouldn't reccomend just going with the runners as you'd be spending $300 or more and I guarentee you'd be dissapointed with the end results. You NEED headers first in order to get the best results from a runner swap.

When you do that, then you should go with the runners. Go with whatever your budget allows you to. Don't skimp out either as the intake is a VERY important factor on whether or not you meat your HP goals.

TPIFormula

Thanx I appreciate the info, I am definitly now considering the headers, Whats your opinion on underdrive pulleys? I might just do the AFPR and pulleys for now and wait a bit on the headers.

LT1FUN

You're welcom. Glad I can help

I don't have underdrive pullies on my 3rd gen so I can't comment on their performance from first hand experience.

Opinions seem to be mixed as far as whether or not they're worth the money.

I've seen many L98's pick up between 1 and 2 tenth's in the quarter with an under-drive pully kit. I've also seen dyno's showing between 10-12HP increase at the wheels.

See, the thing with underdrive pullies is that while they DO work (the upgrade seems paticulary effective on 3rd gen's for some reason) they also have a downside that many people just aren't willing to live with.

A lot of guy's who install underdrive pullies complain that after the instalation the headlights and interior lights tend to flicker or "fade" in and out.

The real purpose of underdrive pullies is to save your accessories from being over revved in applications where the car will constantly stay in the upper rpm range. However if you use an underdrive pulley and DONT stay in the upper rpm range your accessories might not receive enough power. - hence the flickering lights.

If you have a big sound system aswell, it makes matters worse as the alternator won't be able to provide you with enough power to opperate everything efficiently.

Some people have this problem, other's dont. It seems to be hit or miss. It's not a huge problem, but it is a bit annoying. If flickering headlights/interior lights is something you can live with (if it even does happen with you) go right ahead. It will free up some extra HP for sure.

As far as an adjustable regulator, that too seems to be a pretty popular mod with 3rd gen owners. Maybe the TPI motors get better results by adjusting to higher/lower fuel pressure. Maybe someone else who done the mod can chime in here and share their experience.

I had one (Aeromotive) on my LT1 and it was by far the worst thing I've ever done with that car. It NEVER ran properly no matter what I set the pressure to. Not only that but the diaphram broke 3 times and I had to replace the unit (still under warrenty) again and again and again. (Never buy Aeromotive )
I ended up buying a new AC Delco unit and the car ran perfectly.

Again like i said, that was my experience with my LT1. The TPI motors are obviously different so maybe they work better with them.

I'm sure someone else can shed some light on this for you.

MattODoom

iTrader: (1)

My underdrive set came with two pulleys, a smaller than stock crank pulley and a bigger than stock alt pulley. When I installed them both, the car would not stay charged to my content. So I put the stock smaller alt pulley back on (spins it faster) the charging system operates flawlessly, AC, PS and Waterpump are all still underdriven. It doesnt overheat either, constant 180-190 temps (180 Thermo & low temp fan switch installed) and PS & AC work great.

Never took it to the track after the upgrade though.

D's89IROCZ

I disagree SLP are a fair bit better

hookers are nice though ....

As far as the intake goes .... wait untill you get a cam . The intake on you lil 305 isn't that bad for now . I'd take the advice on doing the exhaust first though ....


It all depends how far you wanna go really ?

chickenhawk

If you do go with the SLPs, as was stated, there is plenty of material to trim down but not just on the runner side.

Not my plenum, but here is a pic of exactly what I have done with my plenum to match up with the SLPs. Dont forget to match the TB and intake side as well.

I also have and like the SLP headers. Just a word of caution if you decide to go with them and you have clearance issues with the steering shaft. DO NOT DENT THE HEADER TO PROVIDE CLEARANCE

After searching here, many have suggested pounding a nice dent in the side to make it fit but I couldnt bring myself to do this on a set of 600.00 coated headers. And yes I replaced the motor mounts. Ahhh but my search had ended with the wisdom from an individual that found that there is enough play in the steering shaft mount through the firewall to simply loosen the bolts and shift the assembly over. SLP tech support was no help and gave me the "Ive never heard of this" response, but they now should be passing this on to others as I informed them of this problem\solution for the next poor soul that finds themselves in the same puzzling predicament.

Best of luck with your project.

85rocker

The Firebirds respond very well to a decent cold air setup. Its low hanging fruit I'd do it before spending money on runners.

You can use a large K&N cone plus some parts from Home Depot to get you started.

The 305s respond very well to u-drive pullies. Every time I've done it there was a clearly noticable diff. I too am also only using the crank pulley but it definitely is worth the effort.

From my trials on a 305 the 'runner money' is better spent on hi-flow 3 inch exhaust, headers, cat, etc .

Put some 1.6 rockers in before you do runners.

The stock 305 TPI will work well to about 260-275hp then you have to think about opening it up some.