So I went to the Dyno today with my car. Im curious to see what you guys think it made for power. Specs below.

1991 Z28 350TPI/A4 59K miles on it.

Dyno Don headers and ypipe (no cats)
Magnaflow catback
TPIS intake (port matched to runners)
SLP runners ( port matched to plenum and intake)
airfoil
homemade ram air through foglight openings with K&N filters
Bosch III injectors and AFPR set at 48
EGR deleted
AIR deleted

car has been tuned by a member here through lots of datalogging.


Just curious to see what you guys think this made for power on a Mustang dyno today in 65 degree weather in New England

 

240hp

 

240-250 assuming the compression is good, spark was aggressive enough and you had a correct WOT AFR.

 

234hp 302.5tq

 

Haha you cheated

 

Prove it lol

 

Honestly seems a bit low to me!!! I have seen a stock LT1/6spd with the EFI connection 24x, 0411 PCM, CAI, Catback exhaust, and Electric water pump put down right at 300 hp on a Mustang Dyno.

My Express van 5.7 Vortec with stock valve springs and noticeable valve float running the 395' marine cam, 1.6:1 rockers, L31 Marine intake, Thorley Tri-Y headers, 2.5" dual exhaust to the muffler with Thunderbolt metallic core cats, along with underdrive pulleys put down 230 rwhp @ 4,400 and 304 rwtq @ 3,400 through a 4L85E in 2nd gear turning a 10.5" 14-bolt. Your 700r4/car rear end is losing about 18%. My truck driveline about 25% especially turning a large duramax mechanical engine fan. I have been back on the dyno twice after some small tweaks. I changed to 1.7:1 rockers, LS6 springs and Comp 787 retainers to stop the valve float and adjusted the LS7 lifters to 1 full turn preload from 1/2 turn. The result was 257 rwhp @ 4,800 and 310 rwtq @ 3,200. At 9.6:1 static compression the marine cam was over 8:1 dynamic compression and had 200 psi cranking compression. I was octane limited and installed a flex fuel sensor and put E85 in the tank then tuned for it. I was able to bring the total advance from 29° to 34° and it responded well to as much as 8° more timing into the tune in the 2,400-3,600 rpm range. Power climbed to 272 rwhp @ 4,700 and 330 rwtq @ 2,900. So I will say it again, power seems low to me for that setup. After a few weeks of driving the cleaner burning E85 cleaned the carbon out of the combustion chamber and left the exhaust with a very light gray look rather than diesel soot black. With the carbon gone it runs even better. I ran into something I have never encountered before on E85. Due to its high octane you can actually increase spark advance to the point you start to lose power without running into knock retard.

I have a TPI setup I am thinking of adding along with a cam change recently and I feel the two could be worth as much as 50 hp and matching torque.

Edit-- I have since swapped from the GM Marine cam to the SPO 357hp 350 crate engine cam. I saw as much as 30 gms/sec increase in airflow on the MAF and like clockwork the engine has always drawn about 1 gm/sec per RWHP. In fact just about everything I have ever tuned was similar from MAF TPI, Vortec, LS to Nissan VK56. With a factory MAF and MAF table 1 rwhp per gm/sec flow.

Marine 395' cam
196/206 @ .050
.431/.451" lift w/1.5 rocker
109° LSA
106° ICL

SPO 357 HP
215/223 @ .050
.474/.474" lift w/1.5 rocker
108° LSA
109° ICL

 

At the wheels or flywheel?

If that's at the wheels that's good!

 

Lt1 6spd is alot more power than any tpi L98. 6 spds in general are 5% more power than autos

Auto on a mustang dyno, 234 is doing really good for bolt ons

 

At the wheels. I put down 234/302. That was with some knock retard happening too which I need to address.

 

those are good numbers .. i only made 40 more horsepower on the dyno and added a cam and a set of air flow research heads ..

 

I'm impressed!

205hp on a 69 Daytona!

https://www.velocity.com/tv-shows/gr...a-vs-hellcat-2

 

I think I left some power on the table. I data logged the runs and found that the ecm was picking up knock and retarding the timing. I picked up 5 knock counts at idle and then 3 at 2500-4000 rpm. I think it pulled 5 degrees out.

So, I have to address why this is happening.

 

May or may not be false. Hard to say. No reason it should knock at idle unless something is noisy mechanically. Could try pulling 6-7 deg and seeing if it does go away or not

 

A wild guess, and I'm probably not right. Our ignition systems are extremely noisy. When I installed MS3 it was so noisy I had to turn the filter way up otherwise the MegaSquirt would think there was knock. DIY autotune acknowledged this noise issue to me and said that's why they shield the ignition wires in the harness and they advise running them along with the knock sensor in a separate route or loom. It's a similar issue as when car audio guys run speaker wires along side a power wire.

 

What's the factory head gasket thickness on an iron headed Camaro 350 TPI?

 

My 89 was a shim and i believe it was .015

With pistons .02-.025 in the hole i usually go with gm's composite gasket that is .028

 

I was going to guess 240. Here is mine for comparison.

stock manifolds
GMMG catback, high flow cat
Accel intake
SuperRam (ported)
No Ramair setup, but airbox is cut to be bigger
Stock injectors (died about a month after dyno). Car did feel better after with Bosch III
EGR and AIR still there. Doubt this makes any difference on dyno either way.

85° spring day. I don't think 65 vs 85°F ambients make much difference. Now get down into the 40's and the car feels much faster.

I made 228 HP/286 TQ at the rear wheels. (My intake setup is begging for headers.)

 

You've been speaking past tense lately Justin. If you need a car to mess around with let me know.

I have one I am letting go of very very cheap that runs and drives. PM me if interested..

- Rob

 

Lol i cant afford to own anymore cars. Dumping everything i have into the bbc twin deal. Will be done next year hopefully

 

I've seen ItsMikey 89 Trans Am 350TPI with Dyno Don headers with dual cats made 251whp. Everything else was all stock. You're tuning is off somewhere.

 

I'd like to see that.

 

was the car an auto or manual?

I think he can get there or really close. Problem is something is causing the ECM to pull up to 5 deg of timing out from a factory spark map on a near-factory car.

The AFR is right on the money, so I think the rest of the way will be in the spark timing. It could use some more timing I think, but it's pointless if the ECM is going to pull it back out again.

 

it could be the case also that the tubing used to create this CAI is generating a large pressure drop and choking off the engine. Though I'm inclined to discount this since the TP data indicated he was getting pretty much 100 kPa at WOT.

 

Auto

 

Ok, that's good. So apples to apples.

 

These cars can vary 20 whp depending on condition of motor and the dyno variance as well could make it even more. Take numbers with grain of salt.

 

Yes that's understood. All I'm saying is he made high 230s with questionable timing, so I think he should be able to get solidly into the 240s once the timing issue is corrected.

 

I'd still like to see the CAI. In particular the setup behind the foglight openings.