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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Ok - Our chassis dyno is installed and operational as of today. This was quite the project in itself - 5 months of construction, $75k, the help of many friends, and an 8,000 lb long reach forklift.....
Anyway - for operational testing purposes (RWD tie down arrangement, single roller operation, etc), and just for baseline numbers and for fun, I ran the 86 Trans Am.
So here's the modifications to the engine (original 86 engine - 165k) and drivetrain:
Dyno Don headers, y-pipe, and full exhaust
1.6 roller tip rockers and new stem seals
EBL Flash II
Built 700R4
3500 stall 10" converter
3.70 final drive
And what did it make? 157 HP @ 4k RPM.
I see various numbers thrown around for the 86 LB9. But most seem to agree it was a bad year and the usual quoted numbers are between 185 and 190 crank HP. Given it does have a pretty loose converter - I would estimate probably 20% drivetrain loss. Maybe more? That gives about 193 crank HP. If it was in fact 185, that's not too bad of a gain for headers and some rockers.
Discuss?
Someone got a video of the TA on the dyno, but I was driving so I don't have it at the moment.
GD
Last edited by GeneralDisorder; 06-15-2019 at 05:10 PM.
BTW - I'm tossing the idea of adding to my 305 TPI SLP shorties, SLP runners, edelbrock intake and some head/rocker changes, and porting everything, but have no idea what heads to put on. Will be running 3.42 posi. A top priority is using vintage parts but I could forego the heads. (Are you considering doing something along this line with the TA?) Any recommendations on the heads?
75K is a lot of money just to find out hp for an 86 TA !!
We have been using this dyno at it's former home across town for several years. It's a $100k DynoJet. Due to losing their lease and one of the owners losing interest in continuing the business, the dyno came up for sale. We agreed upon a favorable price and with construction / upgrade costs we are at $75k. But to purchase new and install would have been about $125k. We got a complete upgrade kit from DynoJet to the latest digital "stack" and software, etc. I think it was a great opportunity - we saved about $50k.
GD
Last edited by GeneralDisorder; 06-09-2019 at 01:33 PM.
BTW - I'm tossing the idea of adding to my 305 TPI SLP shorties, SLP runners, edelbrock intake and some head/rocker changes, and porting everything, but have no idea what heads to put on. Will be running 3.42 posi. A top priority is using vintage parts but I could forego the heads. (Are you considering doing something along this line with the TA?) Any recommendations on the heads?
I don't know much about 305 heads but I'm sure there are good aftermarket options. I've seen a couple threads on here with head recommendations.
I have a rebuilt Vortec with a cam and valve train ready to go into the TA. Just have to order a First intake and some injectors.
No, this one is a 350. They did make Vortec 305's though. I have read that the "Vortec" 305 heads do not have the ski ramps and port shape that create the swirling venturi effect that makes the Vortec 350 head such an excellent performance piece.
I'm not sure what you mean by milling? You mean milling the 350 Vortec heads to fit the 305? I don't have any experience with that. But I'm sure someone has done it.
The L30 (5.0L) heads are not downsized carbon copies of the L31 (5.7L) heads. But they were equally effective.
L05 TBI 5.7L to L31 Vortec 5.7L = 200hp to 255hp.
L03 TBI to L30 Vortec 5.0L = 170hp to 230hp.
I wanted a set of L30s, but could just never come up with a pair (they are not common) at a cheap enough price to have them crack checked and rebuilt, and have them still be a good value.
A bit of bench racing here on my part, but curious what other think of this LB9 run.
The '86 LB9 was 215hp at the crank. That's with the better manifolds on the exhaust, so lets say headers are good for 10%, or 21hp. So now we have 236. Add another 5 (conservative) for the rockers, and you are at 241. Less 20% for driveline loss as theorized by General Disorder, that should leave us with 193 at the wheels. So we have a 36hp difference.
I know you can't really "think" your way through these things...the dyno tells the tail. But even with 165k on the clock, if the engine is still in good shape, does that 157 number not seem a little low?
A bit of bench racing here on my part, but curious what other think of this LB9 run.
The '86 LB9 was 215hp at the crank. That's with the better manifolds on the exhaust, so lets say headers are good for 10%, or 21hp. So now we have 236. Add another 5 (conservative) for the rockers, and you are at 241. Less 20% for driveline loss as theorized by General Disorder, that should leave us with 193 at the wheels. So we have a 36hp difference.
I know you can't really "think" your way through these things...the dyno tells the tail. But even with 165k on the clock, if the engine is still in good shape, does that 157 number not seem a little low?
A LOT of sources say 185 or 190 HP for the 86 TPI (no 350 in 86). The dyno numbers make sense for this number. The dyno is accurate for other known HP stock vehicles we have run.
In the end it's pretty academic and just a baseline. Though I am personally of the opinion that the engine was a 190 HP model. Even the 86 sales brochures, which apparently were printed before some changes were made that dropped the power output, list the Pontiac LB9 at 205 HP.
The engine runs excellent and has 160 compression on every cylinder and uses no oil. I have no reason to suspect it's down on power. I have every reason to suspect the engine made 190 HP from the factory though (or thereabouts).
The 10" B&M holeshot converter is non locking. The trans is a 92 Camaro 700R4 built by Ligenfelter. The loose, non locking converter is probably responsible for more than a little wheel HP loss.
GD
Last edited by GeneralDisorder; 06-10-2019 at 12:42 AM.
A LOT of sources say 185 or 190 HP for the 86 TPI (no 350 in 86). The dyno numbers make sense for this number. The dyno is accurate for other known HP stock vehicles we have run.
In the end it's pretty academic and just a baseline. Though I am personally of the opinion that the engine was a 190 HP model. Even the 86 sales brochures, which apparently were printed before some changes were made that dropped the power output, list the Pontiac LB9 at 205 HP.
The engine runs excellent and has 160 compression on every cylinder and uses no oil. I have no reason to suspect it's down on power. I have every reason to suspect the engine made 190 HP from the factory though (or thereabouts).
The 10" B&M holeshot converter is non locking. The trans is a 92 Camaro 700R4 built by Ligenfelter. The loose, non locking converter is probably responsible for more than a little wheel HP loss.
GD
If it started life at 190hp, then yes, these numbers make sense. And I know you are changing it anyway....just thinking through numbers that didn't add up in my mind.
Congrats on having your own dyno btw. That's quite a score.
A couple of you have mentioned the converter now. That one I don't understand. If it's a higher stall, and you are testing at WOT well above the stall speed of the converter, then how does the rpm it flairs to on initial acceleration impact the final HP number?
There is always slip in a converter. Thats lost power. Locking it up so it doesnt slip is true one to one ratio
it always gains alittle power on every car i tried it on. But surprisingly it doesnt always et the best at the track
Also note not all aftermarket converters that have lockup can be locked up at wot...atleast some manufacturers dont recommend it
Here's an interesting note on converter lockup and something that the dyno tech said was happening but electrically, it couldn't be. MY TCC lockup is connected to the 4th gear apply valve in the valve body. That is to say, that unless the transmission is in OD, the clutch will not lock up, Electrically that is. I also have a manual disconnect switch on the dash that was in the open position furthering the incomplete electrical circuit.. Now the tech, when examining the output graph, said that on the two pulls that were made, and these were in little d/3rd gear, a small plateau in the graph indicated to him that the converter was indeed locking up. Didn't make sense to me. Nor did the output results that had a 12 second car producing 288 RWHP. Not sure what to make of that.
Perhaps a little off topic but the discussion around output vs lockup got me to recalling that test.
The converter not being locked definitely affects the number. I'm more curious about how the stall speed effects the amount of loss. I can imagine that lower stall speed converters (when unlocked) probably have *less* slip at peak HP RPM (say 4000 in the case of this little LB9) than a higher stall converter at the same speed. This converter is about a 3500 stall unit, with that number being dependent on engine power. It was previously behind a stage 3 Ligenfelter 383 built back in 92..... hey I needed a trans and this one was the right price and it works flawlessly. And engine upgrades are waiting in the wings so why do it twice ya know?
I'm curious what others think of my 20% drivetrain loss estimate. Maybe it should be higher considering this converter?
Now the tech, when examining the output graph, said that on the two pulls that were made, and these were in little d/3rd gear, a small plateau in the graph indicated to him that the converter was indeed locking up. Didn't make sense to me.
stock type programming has lock up speeds for OD and D. This locks it ar part throttle. At wot there is also a unlock prevention threshold which is what i use. Its usually set between 70-88 mph stock so that once you reach that speed in any gear it will lock the converter. You might have triggered that?
288 whp is welll into the 12’s. My iroc at 3400 lbs total went 12.95 and 12.99 at 103 at 254 whp. My ls1 trans am went 12.11 at 112 with 308 whp in texas negative DA winter air lol. At 3460. 12.52 at 108 at full weight in pa air at 3686 lbs
OK, I see where you are going with the lockup during a dyno pull. But I guess there 2 kinds of accurate here. Locking it may give you a more accurate number in terms of what the engine is producing, but leaving it unlocked is the real world, going down the track RWHP value, no?
OK, I see where you are going with the lockup during a dyno pull. But I guess there 2 kinds of accurate here. Locking it may give you a more accurate number in terms of what the engine is producing, but leaving it unlocked is the real world, going down the track RWHP value, no?
Depends if you use it or not. My cars always were quicker leaving it unlocked. Mph may increase some showing the hp gain of locked converter tho but the momentary drag down of the motor rpm usually hurt my ET some
Gotcha. Thanks for all this info guys. Didn't mean to take the conversation off into the weeds, but this is an area I've never played in (ironic, given my username).
stock type programming has lock up speeds for OD and D. This locks it ar part throttle. At wot there is also a unlock prevention threshold which is what i use. Its usually set between 70-88 mph stock so that once you reach that speed in any gear it will lock the converter. You might have triggered that?
288 whp is welll into the 12’s. My iroc at 3400 lbs total went 12.95 and 12.99 at 103 at 254 whp. My ls1 trans am went 12.11 at 112 with 308 whp in texas negative DA winter air lol. At 3460. 12.52 at 108 at full weight in pa air at 3686 lbs
Ah I see. When I think of a 12 second car I think of 12.00, but most people seem to prefer (gee I wonder why? ) calling it a 12 second car even if it's 12.99, which by all mathematical reason is essentially a 13 second car. I get it though - round down for ET's, round up for ***** size.
I don't race em (yet), I just dyno and tune them. So I just know the dyno says it's not going to make it to 12.00. Now I understand the lingo.
- round down for ET's, round up for ***** size...
GD
Perhaps its more appropriate to say " ..in the 12's..."
As for the other....maybe better left unsaid. But the Canadian used metric system makes measurements very flattering!
Have you dynoed one of the newer TPI cars. As you said the 86 was a bad year I would like to see the difference as I assume the 86 has the peanut cam, crappy heads and is a MAF system.
lmao basically yes. But 12 is a 12 is a 12. If you said run12.0’s then a 12.99 aint a 12.0 haha. Dont round up or down. Only the numbers before the decimal matter for what time class you are considered lol
I would love to see a speed density 91-92 5.0 TPI on the dyno. My 91 auto, 2.73 geared with only a cat-delete ran 14.7s and was rated at 205HP. I always figured more like 230. I just about bet the TPI 081s are just as good as the L30 heads. Id like to see flow comparisons on the two.
I would love to see a speed density 91-92 5.0 TPI on the dyno. My 91 auto, 2.73 geared with only a cat-delete ran 14.7s and was rated at 205HP. I always figured more like 230. I just about bet the TPI 081s are just as good as the L30 heads. Id like to see flow comparisons on the two.
I’m still mad i didnt dyno mine or run it down track. But it felt way slower than my 6.2 silverado which is said to go bottom 14’s so maybe mine was tired. But 9 psi boost made it go 13.4 at 110 so idk
I would love to see a speed density 91-92 5.0 TPI on the dyno. My 91 auto, 2.73 geared with only a cat-delete ran 14.7s and was rated at 205HP. I always figured more like 230. I just about bet the TPI 081s are just as good as the L30 heads. Id like to see flow comparisons on the two.
Stay tuned! My 91 Formula T5, 3.42 will be going straight onto the dyno once it's running. I recently acquired it and I've got to pull the tank as the fuel pump is dead. I did get it running on starter fluid for a few seconds. It's got an L03 long block though
but leaving it unlocked is the real world, going down the track RWHP value, no?
Torque causes acceleration in the real world. Specifically the torque that the tire applies to the ground. Horsepower is just a calculated number.
The most torque is put to the ground in first gear. Each gear shift results in less torque to the ground and slower acceleration.
Engines with wide torque curve and high RPM capability can stay in gear to a higher speed and that can be a big advantage in acceleration. It's not necessarily because the engine makes more torque than another engine, it's because it has RPM range to use gears in a better way and put more torque to the ground more of the time down the track.
It's called area under the curve and it's a difficult concept to explain to dyno customers. They only want to know the peak HP number. And how much peak BOOOOOOST! it made. Both of which are fairly meaningless metrics of actual vehicle performance. I continually have to remind folks that they have ~35psi of "boost" in each of their 4 tires - just no CFM (we hope anyway) to speak of.
Ya, I have a friend with an LS2 that makes nearly the same HP on dyno as my 427 stroker but my car will walk him hard. I make a LOT more torque most the time with a bigger and wider torque curve. If you saw us run you'd not even guess that we make nearly the same peak horsepower.
On the other hand, I have a friend with a LS1 that can walk side by side with me even though I make a lot more peak torque than him. But he has a very wide power band and can hold gear to 8500 rpm. So he's using the rpm range of his engine and gearing to get the same average torque to the ground as me.
288 definitely isn't a 12 second car. Even AWD 300 WHP isn't going to make 12 seconds unless it's really light. Like 2000 lbs light.
GD
At the tires it will EASILY do it. I had a crew cab Nissan Titan that put down 296 RWHP and 388 RWTQ that ran a best of 13.8@ 99 in the 1/4 on a 2.00s 60' time and it was over 5,200 lbs of aerodynamic brick. My M56S put down about 70 HP more STOCK and ran into the 12s STOCK at 4,700 lbs race weight with a 2.62:1 rear gear.
I would love to see a speed density 91-92 5.0 TPI on the dyno. My 91 auto, 2.73 geared with only a cat-delete ran 14.7s and was rated at 205HP. I always figured more like 230. I just about bet the TPI 081s are just as good as the L30 heads. Id like to see flow comparisons on the two.
081 heads are not even in the same ball park as the L30 Vortec heads. Using the same camshaft and rotating assembly the marine 305 engines gained 30 HP when they swapped from 081s to 520/059 casting heads. The Vortec 305 truck engines made the same horsepower as the hotest LB9 with an intake that flows worse, single cat, and a cam that was a full 10* shorter duration @ .050" with less lift. The truck engines also have a slight dish that drops the compression ratio of the L30 compared to the LB9. That is also comparing net rating to net rating, which the F-car has electric fans and the truck a big old clutch fan that eats 8-10 HP by itself. The 081s flow about 195 @ .500 on the intake, the 059s about 220 @ .500 through the same size valve.
I'm actually surprised the 081s flow that much as well as the L30 heads. We did use some L30 heads on a friends 350 and it ran very well. Ive seen 081s on 350s also that seemed to do pretty good for a budget engine.
As a follow up and by way of comparison, (if anyone is interested), here's one of the dyno pull graphs.
That chassis went:
June 12 2009 12.87 @ 105.5 1.77 60’ (3.27 gear *)
Oct 17 2009 12.78 @ 105.1 8.088 @ 83.94 1.71 60’ * (all of the above with McCreay dirt track tires)
You can see on the graph where the torque and HP both have a small peak right around the 100 MPH mark. That's the point where the dyno tech said the converter was locking up. I can say absolutely that there was no electrical connection to the TCC solenoid as I had the manual switch in the open position. Is there a hydraulic reason that locks the clutch when at speed? Unfortunately, no RPM scale was available so I sort of estimated based on the crossover at 5252. Not sure how accurate the MPH scale is either.
Engine specs were: Engine 2007
353: 4.020” x 3.48”
5 cc piston
Resized rods w/ ARP bolts
.030” deck
670 Holley RPM Air Gap Vortec heads. Decked .006”. 63 cc (?)
Comp XR276HR. 276/282, 224/230, 110 LSA, 106 ICL, 64 ABDC IVC
Victor Reinz 5746 head gasket .026” x 4.120”
Mid length headers
10.05 SCR / 8.08 DCR
Cranking pressure 185-190
3700 lbs and a tight converter too. An overachiever if there ever was one. With gears and traction, I'd say bottom 12's for sure but in this case, it was an all street suspension.
GD. You talk about area under the curve. I think part of this car's success was the exceptionally flat torque and HP curves. Not great peak numbers but pretty good average values I think. I attribute that to a well thought out engine plan.
Update. I am getting the new Winpep 8 software setup and figuring things out. Reviewed my pull with the TA after setting up the graphing options, etc. Looks like I misinterpreted the dyno figures. What made it difficult is the really high stall of this converter - meaning third gear lasted a very short time. The numbers for the peak output at the top of third gear (4300 RPM, 1:1) was 185.5 WHP, and 225.7 ft/lbs. Which seems more in line with how the car feels and aligns better with the published GM sales brochure stating 205 HP for the 86 LB9. Anyway I feel a lot better about those numbers.
Adjusted with a 20% drivetrain loss that's 222 CHP and that leaves about 17 HP on the table to be accounted for by the exhaust and rockers, etc. I would guess that the rockers are probably only good for about 2-3 HP, so I think it's pretty safe to assume about a 10-15 HP gain from the Dyno Don headers, y-pipe, and full exhaust. Not bad really.
GD
Last edited by GeneralDisorder; 06-15-2019 at 07:17 PM.
081 heads are not even in the same ball park as the L30 Vortec heads. Using the same camshaft and rotating assembly the marine 305 engines gained 30 HP when they swapped from 081s to 520/059 casting heads. The Vortec 305 truck engines made the same horsepower as the hotest LB9 with an intake that flows worse, single cat, and a cam that was a full 10* shorter duration @ .050" with less lift. The truck engines also have a slight dish that drops the compression ratio of the L30 compared to the LB9. That is also comparing net rating to net rating, which the F-car has electric fans and the truck a big old clutch fan that eats 8-10 HP by itself. The 081s flow about 195 @ .500 on the intake, the 059s about 220 @ .500 through the same size valve.
Is there a drop in replacement vortec 305 head for a LB9 305?
Wow, we all wish we had instant access to a dyno when we do anything to a car. what do you charge to put a machine on that beast?
It depends on if tuning is taking place at the same time.
Three pulls for record and a printout of the best one is $100 on normal business days. We also will be having Dyno Day's where people will sign up for a saturday and we will just strap cars down, two pulls, and pull them off again. $80 for dyno day runs with printout.
Tuning can range quite a bit depending on the car. NA vs. Forced Induction, multiple fuels (or flexfuel), carb vs. factory FI vs. aftermarket FI to name a few...... Say your average TPI third gen that's got to have chips burned is probably going to be $400 or thereabouts. Again depends on how ridiculous the engine is and how many unplanned "adjustments" have to be made on the dyno. Cars come in all the time that are "ready for the dyno" but turns out they aren't and need repairs or modifications that can be accomplished in a reasonable time while strapped down. This adds a significant level of variability to the equation. It depends on who built it and how familiar they are with the process of tuning and what they should be prepared for.
And there's always the clean-up fee if you yard-sale your engine/trans/rear end on my $100k (new replacement price) dyno.
GD
Last edited by GeneralDisorder; 06-15-2019 at 07:18 PM.
Cars come in all the time that are "ready for the dyno" but turns out they aren't and need repairs or modifications that can be accomplished in a reasonable time while strapped down.
Hey guys I wanted to share my experience I also have an 86 LB9 but I was lucky enough to find a set of 059 305 vortec heads for it I put high lift valve springs and extra clearance retainers from Alex'sparts.com then topped it off with a Holley Stealth Ram. my desktop dyno says I'll be somewhere around 330HP. I ported the intake and matched the ports up to the head perfectly. Oh and for those running vortec heads you might want to get a set of those retainers I have clearance up to .550 lift now
My LB9 305 stock bottom end 226HP and 260ft.lbs modifications= L30 head, 420/440 lift cam, Holley stealth ram, ebl flash 2, 24lbs stock 350 injectors. I just dynod the engine has 107k miles and factory manifolds I'll be installing headers and hit the dyno again.
Originally Posted by GeneralDisorder
Ok - Our chassis dyno is installed and operational as of today. This was quite the project in itself - 5 months of construction, $75k, the help of many friends, and an 8,000 lb long reach forklift.....
Anyway - for operational testing purposes (RWD tie down arrangement, single roller operation, etc), and just for baseline numbers and for fun, I ran the 86 Trans Am.
So here's the modifications to the engine (original 86 engine - 165k) and drivetrain:
Dyno Don headers, y-pipe, and full exhaust
1.6 roller tip rockers and new stem seals
EBL Flash II
Built 700R4
3500 stall 10" converter
3.70 final drive
And what did it make? 157 HP @ 4k RPM.
I see various numbers thrown around for the 86 LB9. But most seem to agree it was a bad year and the usual quoted numbers are between 185 and 190 crank HP. Given it does have a pretty loose converter - I would estimate probably 20% drivetrain loss. Maybe more? That gives about 193 crank HP. If it was in fact 185, that's not too bad of a gain for headers and some rockers.
Discuss?
Someone got a video of the TA on the dyno, but I was driving so I don't have it at the moment.
I found timing is best at 34 degrees full in by 3,200 rpm. My next upgrades include headers and subframe connectors. But I also have a fully forged 355 with a cx racing turbo kit and T-76 turbo.
06-09-2019, 12:20 AM
) calling it a 12 second car even if it's 12.99, which by all mathematical reason is essentially a 13 second car. I get it though - round down for ET's, round up for ***** size. 
