Any tips on how to get better acceleration out of an LG4?

Ive got an 83 berlinetta and when i punch the gas, the acceleration really sucks. Any tips on how to get better acceleration?

Put a new engine in the car? *cough*350*cough*

Im planning on putting a new 350 in sometime this year, but im still saving up.

Just don't punch the gas. and then you will not notice the lack of acceleration.

Im planning on putting a new 350 in sometime this year, but im still saving up.

Plan your buildup of the 350 carefully by only buying parts that will swap well from the 305. The exhaust is the first bottleneck to deal with on an LG4, so a pair of Hooker shorty headers and a full 3 inch exhaust will add a good 30 hp just like that :cool:

"a pair of Hooker shorty headers and a full 3 inch exhaust will add a good 30 hp just like that"

gains from headers and exhaust is more proportional to the amount of power the engine makes.
headers and catback on a 100hp 4cylinder import doesn't add 30hp...more like 10.
so with the weak output of the LG4 to begin with i HIGHLY doubt you'll ever see 30hp from the exhaust. 10-15 maybe.

but like you alluded to...it will be needed after the 350 so it's a good thing to do now.

other things to try would be a decent cold air induction, maybe using a snorkel style air filter...which should also work on the 350

bump the timing a few degrees and run good gas

Get 3.73 gears installed, drop an Edelbrock Carb and intake on the car, with a new distributor, open element air cleaner, or a dual inlet air cleaner.

Also, make sure that your TV cable is adjusted right if you have an Automatic.
I got my 86 Trans Am LG4 to run pretty decent with most of the parts I listed above.
http://www.transamws6.com/pics/transam/timeslip.jpg

"a pair of Hooker shorty headers and a full 3 inch exhaust will add a good 30 hp just like that"

gains from headers and exhaust is more proportional to the amount of power the engine makes.
headers and catback on a 100hp 4cylinder import doesn't add 30hp...more like 10.
so with the weak output of the LG4 to begin with i HIGHLY doubt you'll ever see 30hp from the exhaust. 10-15 maybe.

but like you alluded to...it will be needed after the 350 so it's a good thing to do now.

other things to try would be a decent cold air induction, maybe using a snorkel style air filter...which should also work on the 350

bump the timing a few degrees and run good gas

No, I meant what I said. On an LG4 you will get about 30 hp from headers and exhaust. People have done it time and again. It is not due to the 305 having so much potential as it is the HORRIBLE factory exhaust.

this same thing go for the L98. cause if so ill have a new exhaust by the end of next week.

Amen sitting bull, my lg4 has a pair of edlebrock headers and 2.5 inch exhaust all the way back. HUGE difference. (No cat either)

"a pair of Hooker shorty headers and a full 3 inch exhaust will add a good 30 hp just like that"

gains from headers and exhaust is more proportional to the amount of power the engine makes.
headers and catback on a 100hp 4cylinder import doesn't add 30hp...more like 10.
so with the weak output of the LG4 to begin with i HIGHLY doubt you'll ever see 30hp from the exhaust. 10-15 maybe.


Sitting Bull is 100% correct. I've done it, and it makes a HUGE difference. 30HP easily, if not more. Car Craft saw a 50HP increase on a 82 LG4 will just a good exhaust. The exhaust is horribly restrictive.

The LG4s output is low due to lack of airflow in and out of the engine. There's a 215Hp 305 lurking in there with just a good exhaust and intake setup.

Wow.. are you people freaking serious? 30+ h/p with JUST exhuast and intake? That is freaking crazy! *evil smirk* IN that case, I cant wait to get everything I'M planning DONE! lol.
BTW.. nice seeing you again, John!

Can you be more descriptive as far as "the acceleration really sucks"? That doesn't really tell us anything.

Does the car seem to bog down before actually going? Is the acceleration from a standstill or from a 30MPH roll?

I know my car is not fast (stock LG4), but it has enough power to throw my head back a little bit when I punch the gas from a stop. If your car is not even doing that, I think you need to either do a tuneup on the engine or tune the carb.

Yeah headers, 3 inch catback and an open elment really helped my lg4 out!

What kind of intake manifold would you guys recomend for an lg4? That should produce a nice increase in power too right?

Neato.. I can't wait till my Camaro is finaly finished!
But, I would recommend the Performer, Performer RPM, or Holley Stealth intanke manifold for our LG4's. They are kick-ass manifolds!
I would assume that the power increase on an intake manny would be AMAZING, as long as other mods are done to accompany it :)

Edelbrock's Performer EGR manifold will work well. Older cars with iron manifolds (82-82 LG4s) will see more of a gain than the aluminum intake cars (85-87 LG4s and all L69s) will. Typically another 10HP or so for the iron intake, and 5 for the aluminum. GM rated the LG4 with 5 more HP with just an aluminum intake change. The Perfomer RPM would be an even bigger gain. Easily another 15HP or so over the standard Performer. Only problem is hood clearance sometimes becomes an issue and EGR is not an option on the RPM, making them not emissions legal.

An LG4 in decent shape, with good headers, a full 3" exhaust (hi flow cat included), with Performer intake, dual snorkel or open element air cleaner and a carb tuned for the mods should yield over 200HP no problem. Add the Performer RPM and you're near early L98 HP territory.

Gee, the little engine that could (LG4). I want to dump my 350 so I can get all these gains with some cheap bolt ons with this monster. :rolleyes:

87DJP2001 - I've done it. Several others have as well. You haven't. Go away. :mad:

Car Craft documented 240HP out of the above mentioned 82 LG4 with a 750 carb, Performer RPM intake, and full exhaust. Stock heads and cam. Do a search. IMO 225 shouldn't be unreasonable.

87DJP2001 - I've done it. Several others have as well. You haven't. Go away. :mad:

Car Craft documented 240HP out of the above mentioned 82 LG4 with a 750 carb, Performer RPM intake, and full exhaust. Stock heads and cam. Do a search. IMO 225 shouldn't be unreasonable.

Yes, I am going away laughing at all you and the engine that Could't. :bow: :bow:

So the Performer RPM has easily 15 hp over a regular Performer??? That doesn't sound right.

Yes, I am going away laughing at all you and the engine that Could't. :bow: :bow:

Hey no one is saying the lg4 is the high and mighty engine and everyone should get rid of what they have and change over. Were talking about ways to improve it. Is their something wrong with working with what you got and wanting more??? Not everyone can just get a 350. Maybe someones mad because they got beat by the little engine that could :rolleyes:

^ agree 100% (NOthing personal against 87DJP2001 :) )

^ agree 100% (NOthing personal against 87DJP2001 :) )

I agree 100% as well, despite 87DJP2001. The guy has a history here of being a prick, and rarely adds any valuable information without a harsh attitude or a "holier than thou" disposition.

so will this same thing work for an L98??

please tell me yes!!

87JP2001:
My 305 makes 262 RWHP, average as shown on the chassis dyno through the muffler. It traps at 101 MPH and gets 24 MPG on the highway.

Your 350 makes : DYNO RESULTS:
225 RWHP & 296 RWTQ

305's can run. Sitting Bull is right about the exhaust.

Hey ws6transam.. what mods have you done to your car? And how in the HELL have you gotten 26 mpg outta your LG4?

so will this same thing work for an L98??

please tell me yes!!

I wish I could tell you yes, but usually the L98s show less gain from exhaust. While still quite restrictive on the L98, it is MUCH better than the LG4 exhaust. I gained over .6 and 5MPH just from the exhaust. Most L98 guys see about half that.

Wow, that is some crazy bunch of numbers that would DEFFENINTLY help my LG4 out!

Hey ws6transam.. what mods have you done to your car? And how in the HELL have you gotten 26 mpg outta your LG4?

24 MPG. I converted my L69 (not LG4) to a manual T56 transmission. The 0.5:1 overdrive means that at 70 MPH I'm doing approximately 1700 RPM with 3.73:1 rear axle ratio.

Mods? Well, there's a lot of mods, starting at the top:
Home made cold-air induction pulls ALL air from the factory hood scoop:
http://www.ws6transam.org/car/cai.jpg

Then there's the original computer-controlled Quadrajet that has had the tang filed down to flow more air through the secondaries. The metering rods have been changed to a modified set of AU rods that I purchased from JET.

Next is the Edelbrock Performer intake manifold:
http://www.ws6transam.org/car/manifold5.jpg

Underneath that intake are two 1986 305 centerbolt heads with broached pushrod guides. The heads have had 1.94 intake valves installed which have been undercut, and treated to a 3-angle valve job with a Serdi valve cutting machine. The ports have been fully ported (by me) and the combustion chambers have been recontoured around the intake valve to enhance low-lift flow and reduce shrouding. Comp Cams 981-16 valve springs have been installed with steel retainers and 7 degree valve locks, along with 1.52:1 Comp Magnum roller-tipped rocker arms:
http://www.ws6transam.org/car/manifold1.jpg
http://www.ws6transam.org/car/cylinderhead06.jpg
http://www.ws6transam.org/car/exhaust_polished.jpg
http://www.ws6transam.org/car/chambershot.jpg
http://www.ws6transam.org/car/headintk.jpg

Those valves are actuated by a Comp Xtreme Energy cam, P/N 12-242-2, the XE268H. With a 224/230 duration on a 110 LSA, I have it dialed in on a 104 degree intake centerline. It's a rompin' cam in the 305, and the carb has a hard time idling until the oxygen sensor warms up. After that, it goes closed loop and idles just fine at about 900 RPM, and no trouble codes are ever set.
http://www.ws6transam.org/car/305ho_cam.jpg
http://www.ws6transam.org/tasound1.wav

The big intake valve required me to flycut each piston in order to get the proper valve to piston clearance: This involved the meticulous taping off the whole engine so that I could carefully recontour the piston face with a 1/8 inch collet die grinder and a 1/8 inch tapered aluminum carbide cutter. I'd put the piston to top dead center, make the change, then clean up everything and move onto the next piston & start over. It seemed faster than disassembling the whole engine, which due to budgetary reasons I DID NOT WANT TO DO. I used a .015" steel head gasket and obrain a .048" piston to head clearance and a 9.6:1 compression ratio.

At the bottom of the shortblock is a Melling high-volume oil pump with about 90,000 miles of use. It still holds pressure just fine, even at idle, and since the engine had no measureable wear on any cylinder walls, I decided to leave it alone.

The engine uses a modified set of Edelbrock TES headers, P/N 6872. They are designed for the late model TPI application. Since I removed the air pump assembly, I plugged the ports with brass compression fittings so that I can drop a 1/8 inch exposed junction thermocouple into any port I wish to obtain individual cylinder temperature readings. I also cleaned up all welding slag on the inside of each exhaust port so that it matched the cylinder head ports exactly. These headers have been coated with $12 worth of VHT 1600 degree paint, and after four years, they still look almost brand new. In addition, the radiator support was modified to accept a big Griffen aluminum radiator to keep everything cool.

http://www.ws6transam.org/car/headercoat.jpg
http://www.ws6transam.org/car/transcooler05.jpg

On the ignition side, it's Bosch Platinum plugs, Taylor Spiral-Pro wires, Accel Supercoil, Accel ignition module, and a Crane Hi-6 ignition.

The engine is tied to a Fidanza aluminum flywheel for OEM T56 retrofits on a 2-piece rear main seal application, which also has a SPEC stage 2 clutch on it. The transmission is from a 1994 Pontiac Formula. I had to do a LOT of rewiring to get an operational speedometer, but now I have one that reads to 140 MPH.

http://www.ws6transam.org/flywheel.jpg
http://www.ws6transam.org/clutch.jpg
http://www.ws6transam.org/shifter.jpg

Farther down the drive line, there is the ORIGINAL steel driveshaft that has been trued and balanced by K&L Unlimited in Lansing. However, it's vibrating again so it's time to retire it.

http://www.ws6transam.org/car/ds_balanced.jpg

The driveshaft twists a set of 3.73:1 Richmond gears that are bolted to a 1999 Firehawk heavy-duty Gleason/Torsen differential, and a set of Moser 28 spline heavy-duty axles. The brakes have all been upgraded to 1991 F-body 1LE components on all four corners, and it all rides on stock WS6 springs and KONI shocks & struts. It also has some rare ROH ZS 17 x 9.5 inch wheels with polished outers and painted graphite centers. I had to wait six months for these wheels! Then there's the Kenny Brown subframe connectors, the PST suspension bushings, and the Spohn adjustable suspension with T56 retrofit crossmember, & torque arm.

http://www.ws6transam.org/10bolt.jpg
http://www.ws6transam.org/car/rightassy.jpg
http://www.ws6transam.org/car/rohta1.jpg

Since the car now has stick and quick, I soon discovered that it was downright impossible to stay in the seat, ESPECIALLY when using road race tires. Therefore, I had to install a 5-point racing harness, and a roll bar:

http://www.ws6transam.org/car/5ptharness.jpg
http://www.ws6transam.org/DSC00677s.jpg
http://www.ws6transam.org/tigupsidedown.jpg
http://www.ws6transam.org/rb3s.jpg
http://www.ws6transam.org/rollbar_installed.jpg

So, that about wraps it up. I did all the work myself, including the powdercoating. The car has run a best of 14.04 at 101 MPH, but this was the last year for the 305. I'm retiring it. Although it still burns NO oil, and has no knocks, it's getting sidelined for this new motor, which is the project for winter of 2004:

http://www.ws6transam.org/miniram385.jpg

It's all-forged, internally balanced, and loaded for 480 HP naturally aspirated, and nitrous oxide for an additional 250 HP when needed! I'll be using Hooker long-tube headers, and plan on fabricating a lighter weight crossmember that gives me clearance for the exhaust tubes. I'll also convert to either a Global West track link, or a BMR track pack which will move the torque arm pivot point back a foot or two for further exhaust clearance. I also plan on removing the steel rod ends in the suspension and convert back to polyurethane to help reduce some of my rattles.

Sheesh, I probably overdid it on content for this message, and probably hijacked the thread. Sorry about that!
--Dan

Hey ws6transam.. what mods have you done to your car? And how in the HELL have you gotten 26 mpg outta your LG4?

The biggest factor in fuel effeciency is his .5:1 6th gear :)

26mpg isn't that hard to achieve. I'm getting 24-25mpg highway consistently, with only half that around town - but poor city mileage is more due to driver input than engine setup ;)

You however will never see that kind of MPG. Why? You rid yourself of the computer controlled QJet :(

Dan, you didn't hijack the thread.. you simply gave me the answer I asked for :) Thanx, Dan!
Marc_85Z28.. teh Edelbrock I am using is tuned to run lean, so if anything, I will have better mpg than the Q-Jet ;)

Haha, I definitely think JDP875765849030875658596090 got pwned by a 305 at one point in time.

Stock, they are nothing to brag about, but as I mentioned earlier, my 305 with a new carb, edlebrock intake, and edlebrock tes headers and no cat with a recent fresh tuneup let me run almost kneck and kneck with some real nice new BMW, that my buddy that was with me said was fast as hell. They guy nodded at me and my window was down and I just said "yeah right, I only got a 305." So he just kinda laughed and I looked at him again and said "Ah, what the hell". and smiled. Light turned green, I layed on it, the quadrajet didnt bog, the 305 put me in my seat and i gave a pretty damn respectable run to a 2004 BMW coupe. With a cam and lifter seat, I can almost GAURENTEE everyone here that I would take that same BMW, easy. So the "little engine that couldn't" has just became the little engine that "could".

You preach it, John! I back that Guarantee up 100%!

Marc_85Z28.. teh Edelbrock I am using is tuned to run lean, so if anything, I will have better mpg than the Q-Jet ;)

Lean or not, it will NEVER be capable of providing better gas mileage than a CC QJet. You were astonished to see 26mpg on a 305, so common sense would tell me you're nowhere near that mark. 20+ mpg is commonplace among the CC QJets, and many see above 25 mpg. Holley, Demon, Edelbrock, etc just cannot offer the same fuel effeciency, tuned lean or not.

Well, I still have the stock QJ on it right now. BUT.. the car, in all it's 197k, has NEVER been tuned up, the carb was loose, the intake man. was loose, exh. man was loose, the plugs were loose, the O2 sensor is shot henceforth causing the carb to go full-rich, and the Dist. cap was totally mangled. So.. I dunno if THAT was a factor... but I went thru 1/4 tank going maybe.. 6 miles at MOST.