quote Originally posted by Matt Hawkins: We use 4th because it is closest to 1:1 in the getrag. Also, it gives a longer duration pull for checking air/fuel ratio. Matt

The idea that a manual car should be dynoed in 4th is a carry over from longitudinal cars. American 4, 5, and 6 speeds couple the input shaft directly to the outpur shaft in 4th gear, bypassing the countershaft. This is the configuration for which drivetrain loss is the least in a longitudinal car.

Using a transmission like the Getrag, the dyno gear doesn't matter from a loss standpoint because all gears transmit torque through one spur gear interchange.

However, the longer pull is a good reason to dyno in 4th. If the dyno samples fast enough (or the car is slow enough ), there's no reason you can't dyno in 3rd, as long as you get acceptable RPM resolution on the readouts.

Good call Will. We want the 1:1 for the time to pull. Since I am using a wideband O2 sensor, I want the run to be smooth and slow to allow for accurate air/fuel readings. It is much easier to tune when there is less dynamic change. The wideband isn't instantaneous, so the slower the RPM change the better.

Matt

those are some wicked numbers man, very impressive. I noticed in the dyno graphs that the lines get kinda sketchy in the upper rpm range. Is that knock? Looks like it to me. You might want to look into alcohol injection. Man that stuff is wicked

I just love how exotic a 3.4TDC sounds. Especially with that turbo whine. You guys need those Super Sequential Bird Whistle Blow Off Valves (TM)

BTW: 85frankenstein, the car PC page on DOHC.com has an incorrect syntax. All the pics use a \ instead of a / in the url's. Sure, I can fudge them so I can see them, but some visitors might not be able to figure it out.

Anyway, keep up the awesome work guys, sweet turbos!

Cheers,
Kris

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Little, Yellow, Different New sig pic with 17's coming soon!

fieroX - That noise is way out of balance tires. The amplitude and frequency would be identical on each run. You could lay the traces over top of each other. I am taking care of that tomorrow. You should have felt the thing vibrate on the dyno at 6300 RPM in 4th.

I was very carefully watching air/fuel ratio and timing to make sure there was no detonation. Did you get your tranny fixed? Are you going to make it to the 20th?

Matt

[This message has been edited by Matt Hawkins (edited 07-01-2003).]

im still having tranny problems, I think its the torque converter. Im going to buy the intense hd converter that stalls 400 rpm higher than stock, and has all that crazy crap inside that I cant break. Im getting my scanner tomorrow, so I can find out exactly what is going on inside there. And nope I wont be able to go to the 20th, I just got a new job at a body shop, finally making some real money, and i wont be able to get away. Maybe the 40th

Hey Kris,

thanks for the heads up. I just switched them all, but it's funny that IE doesn't error out with the slashes either way. That's why I didn't even know there was anything wrong. Guess that's what I get for doing a page the "Old Skool" way, with notepad. LOL Been a long time since I did it that way and it obviously showed.... It all fixed now...

Bob

Hi Matt, those are impressive numbers, I was wondering where did you get your car dyno'd and would you recomend them ? I keep meaning to get my V8 set up correctley, although I do not expect power numbers like yours, from a basically stock smallblock. See you at the 20th drag races, I will be behind you trying to catch up !!!!

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84SE, aero body, 5 speed and a 350 V8

A friend of mine works at Bosal Exhaust in Ann Arbor. I did the dyno work there. Track me down at the 20th and we can chat.

Matt

Here's some intersting numbers from the Flow Dyno today... What do you think about a set of full race ported heads for the 3.4L TDC/DOHC motors? Last I checked, they ran over $2200 for the set, a bit less for a simple street port. For what? 10 - 15 cfm?

I just got back our new DMS Race Ported Heads for the 3.4L TDC/DOHC and had them flow tested today for documented increase over stock... Wanna guess the improvments?

Stock 1991 heads flow 270 cfm... a GOOD increase in performance would yield around 20 additional cfm... wanna guess?

Try 47, yes FORTY-SEVEN additional cfm!!! That's 317 cfm from out new heads!!! Exhaust is up to of course and we managed to land the ratio at the perfect level, 65% of Intake. Incredible numbers!!!

More incredible numbers...

These Heads can be done by DMS with a complete Valve Job for under $1500 for the PAIR. Street Porting is available also for under $800 for the pair and results show about a 20 - 25 cfm increase in flow, still incredible results.

Now THESE will go nicely with a big, fat Turbo!!!

Let us know if you are interested!!!

DKOV -
DMS

quote Originally posted by Matt Hawkins: fieroX - That noise is way out of balance tires. The amplitude and frequency would be identical on each run. You could lay the traces over top of each other. I am taking care of that tomorrow. You should have felt the thing vibrate on the dyno at 6300 RPM in 4th. I was very carefully watching air/fuel ratio and timing to make sure there was no detonation. Did you get your tranny fixed? Are you going to make it to the 20th? Matt

Matt, detonation will not be easily detectible by watching A/F ratio or timing advance. You really should have a knock gauge on any boosted engine to directly monitor detonation. Also, what is your A/F ratio under boost? I don't have a wideband O2 on my 3800 Turbo but it seems to like a standard 02 voltage reading of .92-.94 underboost whereas the earlier grand national turbo 3.8's like to see .720-.860 or so. I know if you run older 3.8 turbo engines into the .900 volt range on the O2 you will almost certainly detonate as fuel puddles in the cylinders. Perhaps the series II 3800 I have likes more fuel because the combustion chambers have a better design? who knows. still, I would put a knock gauge on or watch the scan tool for knock retard while you are under boost just to be sure.

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Fiero-related Conversions Performed:

1985 SE 3800 Series 1 SC 4T60-E
1987 Coupe 3800 Series II Turbocharged 4T60-E
1987 SE 3.4 TDC 5-speed
1984 Coupe SBC V8 non-OD to 4T60 OD swap, electric power steering install
1985 SE 3800 Series II Supercharged 4T60-E

http://dtcc.cz28.com

Darth Fiero - I am running an air/fuel rato of ~12:1 under boost. I must warn you that a normal O2 sensor is a dangerous way to tune the air/fuel ratio on a boosted engine. I read the same things about GNs, but once I put the wideband sensor in, I realized that the normal O2 sensor isn't accurate at all. It isn't even consistent. Just a warning. I am going to remove mine from the car because of this.

As far as detonation goes, you can see it on an inertia dyno if you look closely. It is usually very sharp spikes on the power curve. While there were hugh fluctuation in mine, they weren't sharp changes and way to slow a period for that engine speed. They will be proportional to the engine speed. The problem with a knock sensor is they don't work well at high engine speed due to valvetrain noise. I am running a max of 23 degrees timing on the top end. Not nearly enough to cause detonation with 9 psi and a 12:1 air/fuel ratio. You seem to like boosted engines. Don't tell anyone our secret!

Matt

Hey matt... I was just curious how y'all did at Milan... didnt see anything 'bout ya in the other thread altho i haven't checked back to that thread in a little while so i coulda missed it... i'm real curious to see what these two turbo engines ran...

-Daniel

very nice !
looks like the tuneing is right on

is that an a/w intercooler, if so id love to get the details

what are you using for fuel, ignition and boost control?

from what i can see you are running the injectors pretty close to the edge (almost time for the 50lbers)

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84 Fiero Turbo Vortec 4300 Phantom GT
L35 block
Syclone Intake and ECM
T04B H3 Turbo
http://www.cardomain.com/id/vortecfiero

"Any significantly advanced technology is indistinguishable from magic"

D-Ri2k4 - The cars both ran well. The starting line was an ice rink, but they still respresented the turbo crowd well. I ran 13.3 @ 104+ using 11psi. Steve ran 13.2 @ 113+ pushing 18 psi. His 60ft times were terrible. On the order of 2.5s. With a little more boost and better traction at the launch, I see no problem running in the mid 12s. Until then no promises, but I don't think it will be a problem. Don Kraus was the king that day. He ran 12.0 @ 110+. It's amazing what a set of drag radials will do for you!

vortecfiero - The intercooler is air to air. I am using a Haltech E6K for spark and fuel. It uses the stock distributorless ignition from the 3.4l. Since I am running batch fire, my duty cycle for the injectors was only at 70%. That gives me plenty of room for more power. Those 38lb-hrs would never be enough with sequential injection though. You got that 4.3l running yet? That thing should scream.

Matt

quote Originally posted by Matt Hawkins: D-Ri2k4 - The cars both ran well. The starting line was an ice rink, but they still respresented the turbo crowd well. I ran 13.3 @ 104+ using 11psi. Steve ran 13.2 @ 113+ pushing 18 psi. His 60ft times were terrible. On the order of 2.5s. With a little more boost and better traction at the launch, I see no problem running in the mid 12s. Until then no promises, but I don't think it will be a problem. Don Kraus was the king that day. He ran 12.0 @ 110+. It's amazing what a set of drag radials will do for you! Matt

That 113mph trap speed indicates the same problem my nitrous'd 66 mustang had... traction... and I guess mine wasn't quite as bad as yours, I could plant about 520hp once I got to around 90mpm.... smoke show under that at will. I'd say the trap speed indicates the car is capable of low 12's or high 11's if you can plant it without breaking. Since every 1/10th you knock off the 60 foot time normally quadruples buy the end of the 1/4... if you got it down to a 2.0 even your talking about knocking nearly 2 seconds off that ET. IE... get some slicks.

hey what's a dyno test cost about? I want to when I finish my swap and I know other peolpe who want to with GNs but never thought about the cost. If you don't mind me asking.

quote Originally posted by Matt Hawkins: Since I am running batch fire, my duty cycle for the injectors was only at 70%. That gives me plenty of room for more power. Those 38lb-hrs would never be enough with sequential injection though. You got that 4.3l running yet? That thing should scream. Matt

What? Batch vs. sequential shouldn't matter for duty cycle unless you're doing some weird extra-rich fuel-cooling-the-intake-charge thing.

matt check your emails, i sent an email regarding a main girdle...i need to make one for my TDC and i was curious if u wanted to "join forces" to get one for each of our motors...let me know, later.

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Eric
'87 GT 5-speed Gold/Tan NOW with a 4.10 4-speed <- edit broke 4.10 back to 3.65 4-speed
3.1 TDC + other goodies F/S $900 (no ECU or harness) PM or email for more info....

SAVE THE SHAUN!!!

Will - Since I am batch firing, the injectors squirt twice for every combustion stroke. Once per revolution. Not once per cycle like sequential (once every two revolutions).

Coinball - I will respond to the e-mail today.

Matt

quote Originally posted by Matt Hawkins: Will - Since I am batch firing, the injectors squirt twice for every combustion stroke. Once per revolution. Not once per cycle like sequential (once every two revolutions).

That doesn't affect duty cycle. There are still 20 ms between intake valve openings at 6000 RPM. Whether you're splitting that into two 5 ms pulses or one 10 ms pulse doesn't matter, since both are 50% DC. Actually, you'll get more fuel out for the same on time with one injector event per revolution because the injector spends less time in transition.

It does affect duty cycle for available time to inject. As you said, I can split it into two 5 ms pulses (batch) or one 10 ms pulse (sequential). But, two ten ms pulses are also available. The duty cycle is the amount of time the injectors are open divided by the total time available for fueling. In this case, it is twice what a sequentially fueled engine would be. If at 6000 RPM, there are 20 ms available for sequential, I have 40 ms available for batch. Sure the fuel is going to sit on the back of the valve, but it's still there. Yes coil saturation time does come into play, but I will always be able to put in more fuel with batch than sequential (assuming same size injectors).

Matt

No, the amount of time for fueling at a given RPM is fixed. At 6000 RPM there are 20 ms between intake valve opening events regardless whether the injectors are fired batch or sequentially. Two 10 ms pulses are 100% duty cycle just like one 20 ms pulse. The difference is that there's another injector close/open cycle in the middle which reduces total fuel delivery slightly.

Matt, are you using a fan for your intercooler? I bet if you put in a small electric fan, it will help cool your air charge better.

IROC

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1986 Pontiac Fiero 2.8
pocket ported, gasket matched complete intake. Still has no nut.
3.4l turbocharged project in process!

http://www.outwar.com/page.php?x=1033721

So what if I lost everything, would you want me if I was a failure?

I see what you are saying Will. But most sequential systems only allow you to use the time during one half of the combustion cycle (one crank rotation) to inject fuel. The crank cycle leading to the valve opening. That is why I say I can put in more fuel with batch firing. The Haltech says I am only using ~70% duty cycle at my current power level.

IROC - Currently I don't have a fan, but I plan to add one. A Mustang scoop on the back is also planned. Gotta get that heat out of there somehow!

Matt

Matt - man... with those traps speeds y'all should be runnin in the low 12's to 11's... I was just at a car show talkin to a guy with a procharged and intercooled C5 'vette running 12's with a 135mph trap speed... he couldnt for the life of him catch traction... and thats with 335mm street tires out back... he also said he was gonna get some drag radials before he goes to the track again... heh... hell... stick some mickey thompson cheaters on there

heh...

-Daniel