Went to the dyno with my local car club last weekend and was very disappointed with my results. I took my '86 Trans Am 305 TPI 700R4. My only mods are an LT1 cam and headers. My numbers were 153hp and 200lb-ft at the wheels. Seems like it should be making more power. Any ideas what I should look at first to improve these numbers?

Here is the graph:

 

Well, it is a small cam/small head motor with headers. Dont know what they put out stock. Was it tuned at all?

If this helps to ease the pain-

Many yrs and a couple motors ago I took my 67 to be dyno tuned, ran etc. Thought that 350 something with an Isky 280 cam, camel humps, Z28 intake headers big holley etc. LOL


180rwhp 280rwtq

I about cried..

Lots of torque converter slippage
Ran on an old water dyno

Thing is the car ran strong thats all that mattered. Kinda
Worst part is Id called most my then friends and announced what I was going to do, then the calls came that night, this end of the phone was a lil quiet.

 

You

 

You dont hear about many people being happy about their dyno numbers..

 

Have you done a custom tune, or are you on the stock tune. I think even a stock 305TPI should be 190hp.

 

Recheck you timing. Make sure you unplug the single est wire first.

 

No tuning to speak of. I am running an '89 .bin 'cause the long block is out of my buddy's '91 T/A (he went LSx) and with the later intake I needed a .bin that doesn't need the 9th injector for cold starts. This engine in my buddy's car with the only difference being a Stealth Ram made WAY more power (I'll see if I can find the numbers). I wouldn't mind if I was at least at stock power levels. Figuring 20% loss through the automatic, I'm at about 194hp and 257lb-ft at the crank. Stock is 205hp and 285lb-ft.

 

190@4000 285@2800

stock numbers...what you got is about what you shouldve expected especially with zero mods to speak of really.

these cars dont gain hp/tq with age

 

GM rated their numbers at the crank tho.. So 190hp would be alot less whp.

 

Figuring 20% loss through the automatic, I'm at about 194hp and 257lb-ft at the crank.

hence why he said this

 

The Standard Catalog of Firebird shows the '86 LB9 rated at 205hp and 275lb-ft and the '91 LB9 at 205hp and 285Lb-ft. My ECM w/MAF is '86 and the long block is '91 so not sure where mine should fall. Obviously my torque is well below where it should be.

 

https://www.thirdgen.org/1986-pontiac-firebird

the numbers i posted come directly from this sites tech....and to be honest i think they are closer to realistic, there are some "freak" cars that made a bit more but you fall in the range of what i would expect

 

Not to the wheels. Those numbers are fairly close to what I'd expect out of an '86 305 TPI - The cam SHOULD make some more power, but in the end, you're close to stock numbers at the wheels... lol

 

Torque should be higher.

 

Even with a 20% loss, he's at 183hp at the crank. With a Lt cam and headers, it should be over 190 at the crank, and i'm not sure but the air fuel table looks low to me.

 

The automatic is sucking the life out of that car, along with 30 years of power loss. Really you should be happy with how little you lost after 30 years, my brother truck was a 1978 350 and and he barely cracked 150 hp and 180ft-lbs of torque on the dyno and he had big cam, intake, headers, and so on. Needless to say he was less that satisified, he went for the big block after that.

 

The motor is 20yrs old, and if it has good compression and a solid tune, he should be better than stock in my opinion.

 

As I posted above, that same engine was in my buddy's '91 T/A with a Stealth Ram on it and it made 235 hp / 256 ft lbs at the wheels (on the same dyno I might add). I can understand the hp gain with the HSR, but it shouldn't be good for 56lb-ft!

I think you hit the nail on the head. I am picking up an ALDL cable from my friend next week so I can start doing some data logging. Then I guess it'll be time to learn to edit the .bin.

 

My stock peanut cammed lb9 with a cat back and CAI dynoed at 165hp and 255lb/tq at the wheels. In theory you should have at least 20hp over that with a little less torque.

I thought '86s were non-roller.

 

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As I posted above, that same engine was in my buddy's '91 T/A with a Stealth Ram on it and it made 235 hp / 256 ft lbs at the wheels (on the same dyno I might add). I can understand the hp gain with the HSR, but it shouldn't be good for 56lb-ft!

I thought '86s were non-roller.

 

Just to reiterate, the long block is from a '91 Trans Am.

 

What RPM was the torque peak on his? It could be stall speed flash if he's running a converter with a higher stall speed than the RPM started. Also make sure his dyno numbers were adjusted to SAE and not STD (standard will read about 5% more). Did he have long tube headers and you have shorties (that can make a big difference)?

If he wasn't running cats,, or was running two cats or had new/high-flow cat(s) and you're running just one and if it is old/stock,, that could account for a large difference. Also,, if his transmission was fresh and yours has some miles on it,, there can be a BIG difference just with the different transmissions.

 

His numbers were from the same dyno. He also had a T56 on it which I'm sure accounts for at least another 5%. Not sure what he had for an exhaust.

 

time for some tuning IMO.

 

Good running stock L98's typically make about 195-210rwhp. A good running LB9 with the non peanut cam would probably dyno 15 to 20 less than that.

A more accurate gauge is your cars trap speed. If you know the race weight (dont' estimate, find a scale most strips have them somewhere)

My GTA scaled at 3770 with me in it, my 25lb laptop bag, and misc stuff (gallon of coolant, 2qt trans fluid, 2qt oil, and lightweight tool kit). It trapped about 103mph.

The calculators put that about 320fwhp, would probably be about 250rwhp. All of my runs were with a unlocked converter.


Dyno drag racing is pointless. You can have 3 back to back runs all varying by 10rwhp. You can do it on 2 different days and get even bigger differences. Then you can do it between different types of dyno's and get tons more than that.

The real truth is how fast your engine can get the car down the track. ET is irrelevant to power calculations. Trap Speed is king.

 

This.

However, your A/F ratio on that 3rd run was under 12:1. That LT1 cam is a decent jump up from stock, and needs tuned accordingly. Hell, I had my LS1 tuned for just BOLT-ONs, let alone a camshaft.

Just remember dynos are tuning tools.

Get the tune under control, hit the track, and report back.

 

Yes, a tune is required. The MAF can make up for alot. but its still not an A.I. It works within a set group of tables.

I'm going to have to have my car tuned on a dyno after the heads/cam. Sure, it'll run. But not well.

 

Oh, gocha.

 

I agree with the comments I've read, but the most important one was the first reply. The 305 heads are just not up the flowing what the LT1 cam can provide. Look at what LT1 heads flow and get some after market 305 heads that flow simialr to LT1. AFR, Trick Flow and World Products all come to mind. You have to carefully match components. And the stock TPI runners will only allow so much flow so thye have to be improved as well so you get greater flow in and greater flow out, think of the engine as an air pump. TPIS & Edelbrock offer high flow runners.

 

Don't miss the obvious stuff like IS THE THROTTLE GETTING WIDE OPEN? Is the base timing set correctly (should be about 10* initial for best results with a stock tune)? Is the fuel pressure set correctly? Do you have 19 lb. injecors in the TPI like the programming will be expecting?

What's the difference between the two runs? The A/F ratios are different by more than one full point.

An LT1 cam isn't much different than a stock cam (mostly just more lift), unless you compare it to the "peanut cam" your 86 came with originally. And headers don't make that big a difference. A stock tune might not be optimal but you're way low- more than I would expect even a sharp tune could make up for.

 

I actually have 22lb. injectors 'cause the previous owner was gonna put a 350 in and never got around to it. We did change this in the bin.

All 3 runs were done back-to-back so the only difference was temperature and it never got above 220*.

One of the guys in my club took a look at the bin I'm using and determined that it is not a stock bin as alot of tables have been zero'd out. We are gonna get the correct stock bin, go over the timing tables, reset base timing, adjust the TPS, and then see where we're at.