Announcement

**DHolmes** · 08-24-2007, 01:38 PM

something wrong ,seems very low

**ConElite** · 08-24-2007, 01:42 PM

For some reason to me that seems extremely low. For all that work I would guess it should be around 325-350rwhp.The 58mm TB is not going to make that much of a difference. Its max amount of power you get is like at 60-75% WOT if you are pushing less than like 500hp. The 52mm would have been a better choice, or even the stock one. Drag Radials are a Must no matter what. Best Bang for the buck at the DragStrip. Can knock off anywhere from .1-.4 If your going to run DR's on the street I recommend some Nitto DR's. They work Pretty well in wet surfaces, and real well in dry.

P.S. Welcome to the Forum.

P.S.S. You have pictures of this thing. Sounds Awesome!!

**Jeff_in_Atl** · 08-24-2007, 01:51 PM

What is your fuel pressure through the rpm range? (not just at idle)

**69LT1Bird** · 08-25-2007, 05:54 AM

Thanks for the replies. I am thinking that the dyno guy may have run this in overdrive. I figured I would go with the 58mm since the engine will only use what it needs and the price was the same. 325-350 is about what I thought too. I guess I will work on the tune a bit more and see what happens.

Attached Files

**Jeff_in_Atl** · 08-25-2007, 07:21 AM

Originally posted by 69LT1Bird

Thanks for the replies. I am thinking that the dyno guy may have run this in overdrive. I figured I would go with the 58mm since the engine will only use what it needs and the price was the same. 325-350 is about what I thought too. I guess I will work on the tune a bit more and see what happens.

If you are not going to respond to questions asked or the responses you get there is no point in asking a question on here.

**69LT1Bird** · 08-25-2007, 08:26 AM

Originally posted by Jeff 95 Z28

If you are not going to respond to questions asked or the responses you get there is no point in asking a question on here.

First off, I was responding and also making a statement. I need to go for a drive with the pressure gage but it is raining. The last time I checked it there was now problems there. The dyno sheet shows the A/F ratio to be fine With attitudes like yours itssurprising anyone will even ask a question. You are not the only one who responded.

**MunsonGTA** · 08-25-2007, 10:42 AM

that cam and intake aren't really that well matched. an lt4 hotcam or something similar would be a better match to the lt1 intake. the zz4 is made for torque and really goes with the tpi intake. the lt1 intake is a mid range setup and the zz4 cam is a low end cam.

**69LT1Bird** · 08-25-2007, 11:11 AM

That makes sense. I did not think about the runner length until I started to research this a bit further. I originally went with the ZZ4 cam for the lower duration but that may have been a mistake. Other than the hot cam, can you recommend anything else that may fit my current setup. I think I may have to get desktop dyno and start looking at some different setups.

**Injuneer** · 08-25-2007, 11:57 AM

ZZ4 cam

Not enough cam.

The ZZ4 really favors "exhaust" at the expense of "intake"..... look at the specs, less intake lift and duration than the LT4 HOT cam, a huge 13-degree split favoring exhaust. That is not a high RPM cam.

0.474/0.510 lift @ 1.5X
0.505/0.544 lift @ 1.6X

208/221-degree duration

Compare this to the LT4 HOT cam:

0.525 /0.525
218 / 228

And the LT4 HOT is considered "mild" for an LT1 350 setup.

ported and polished heads - Iron heads

Give us some flow numbers. The iron heads flow a bit better than the aluminum heads, but once you port them, its up to how good the porter is. And, the iron heads will generally limit ignition advance, compared to an aluminum head. While the aluminum heads remove heat faster from the combustion chamber (bad), it also allows more timing advance.

3 angle valve job

nothing unusual

port matched intake

Again, what does this mean? Gasket match? The stock LT1 intake flows fine for most applications. A good port job, done by the person who ported the heads and knows what the heads need, may pick up a little flow, but not much. Were the heads and the intake ported by the same person, and flowed together to test the results?

F car MAF sensor

Is not limiting power. Has it been hacked up?

30 lb SVO injectors, had to, duty cycle was 100% at WOT

100% DC on a 24# injector (is that wht the Impala engine has?) would indicate the engine was making about 355 flywheel HP or about 290 rear wheel HP through the 700R4. Matches the dyno results.

CAI

Which one?

1.6 rr

See cam comments above.

160* thermostat

Have the fan on/off temps been reprogrammed?

adjustable fuel pressure regulator

What pressure do you have it set at? I think this was what Jeff 95 was asking about. I don't think he expected you to run out and measure it. I think he expected you would know where you set it.

hedman short tube d port headers

I assume these are necessary to fit the engine in your car. Sounds like they may be a limitation. What is the primary tube and collector diameter?

Pypes 2 1/2" mandrel bent exhaust with X pipe Pro Flo mufflers

Sounds good

LT4 knock module

OK

all free mods

List them. TB bypass is good. Porting the MAF is bad. What have you actually done?

700R4 with all the toys inside

What is the stall on the converter? Is it a locking converter? Was it locked up for the dyno pull?

3.73 12 bolt rear end

OK

Brian Herter initial tune, some tweaking since

Tweaked by whom? Did Brian know about the F-Body MAF? If fuel pressure is not stock, did he know what it was?

Heads and cam may be a poor choice, or may not be what they claim to be. Headers could be a limit. An altered MAF may be a problem.

A helpful hint based on being here for about 9 years.... don't get into an argument with people who tried to help you. It doesn't help you get answers. JMHO

**69LT1Bird** · 08-25-2007, 06:12 PM

ported and polished heads - Iron heads
This is a basic gasket match, pocket port, clean up. No flow numbers. With the 160 stat this thing runs very cool in this car, 160-165 at the right head

port matched intake
Again, what does this mean? Gasket match? The stock LT1 intake flows fine for most applications. A good port job, done by the person who ported the heads and knows what the heads need, may pick up a little flow, but not much. Were the heads and the intake ported by the same person, and flowed together to test the results?
Just a gasket match and clean up of casting flaws

F car MAF sensor
Is not limiting power. Has it been hacked up?
Not de-screended, stock from F car 3 1/2" MAF

30 lb SVO injectors, had to, duty cycle was 100% at WOT
100% DC on a 24# injector (is that wht the Impala engine has?) would indicate the engine was making about 355 flywheel HP or about 290 rear wheel HP through the 700R4. Matches the dyno results.

CAI
Which one?
Custom. 4" polished aluminum pipe ran out in front of the rt wheel well and closed off from the engine compartment and a K &N on the end. IAT is located at the end near filter. PCM shows almost ambient air temp

1.6 rr
See cam comments above.

160* thermostat
Have the fan on/off temps been reprogrammed?
Yes, on at 189 off, can't remember.

adjustable fuel pressure regulator
What pressure do you have it set at? I think this was what Jeff 95 was asking about. I don't think he expected you to run out and measure it. I think he expected you would know where you set it.
45 psi

hedman short tube d port headers
I assume these are necessary to fit the engine in your car. Sounds like they may be a limitation. What is the primary tube and collector diameter?
At the time I didn't think the standard camaro headers would fit but I see they will cover the D port opening. I may have to look into long tubes.

Pypes 2 1/2" mandrel bent exhaust with X pipe Pro Flo mufflers
Sounds good

LT4 knock module
OK

all free mods
List them. TB bypass is good. Porting the MAF is bad. What have you actually done?
TB bypass, yes. Port MAF, NO. The IAT relocation.

700R4 with all the toys inside
What is the stall on the converter? Is it a locking converter? Was it locked up for the dyno pull?
2400 stall, Lockup. No, it is setup to lockup in 4th only and I found out later that the TCC solenoid was not working,

3.73 12 bolt rear end
OK

Brian Herter initial tune, some tweaking since
Tweaked by whom? Did Brian know about the F-Body MAF? If fuel pressure is not stock, did he know what it was?
Tweaked by me after driving the car and logging data from datamaster. I didn't change a lot just fixed some timing in a couple of areas. Yes he knew about the fuel pressure.

Heads and cam may be a poor choice, or may not be what they claim to be. Headers could be a limit. An altered MAF may be a problem.

A helpful hint based on being here for about 9 years.... don't get into an argument with people who tried to help you. It doesn't help you get answers. JMHO
I wasn't looking to pick a fight I just was looking for a little help, not asking for much. I have a ton of automotive experience and don't like to be treated like a 16 year old

**Jeff_in_Atl** · 08-25-2007, 08:24 PM

Originally posted by 69LT1Bird

I wasn't looking to pick a fight I just was looking for a little help, not asking for much. I have a ton of automotive experience and don't like to be treated like a 16 year old

I wasn't treating you like a 16 year old. I asked a question. You came back and didn't answer it. How can help if I need a question answered and you don't answer it. It's just frustrating when I take the time to try and help. Especially with the conversion you have done. Your car didn't have any provisions for a high pressure pump that is required for fuel injection so I figured it was an external pump. I was just wondering if the fuel pressure was dropping off at the high end causing the reduction in power.

**69LT1Bird** · 08-25-2007, 08:56 PM

First I would like to apologize. I didn't mean to offend anyone. I do appreciate any input on my question. You are correct in that I have an external pump but my fuel tank has a baffle/reservoir inside that keeps the fuel on the pickup at all times. I have a 255 lph pump and I have never experienced any type of starvation or lean out because of the pump setup. I did the same basic conversion in a 66 Chevelle and that car has never had fuel issue either.

**Joe 1320** · 08-26-2007, 11:27 AM

I agree with Fred, the Cam is a mismatch for the rest of the combination. Might work ok with some sort of power adder. Favoring the exhaust would be a good thing with a pressurized intake.

**Injuneer** · 08-27-2007, 05:41 AM

The stock HP rating on the ZZ4 crate engine is only about 355HP, if I recall correctly.

Scratch my duty cycle vs. HP numbers for the 24# injectors. That was not correct. 100% DC would be 400-425 flywheel HP, dependant on how efficiently it was tuned. From my experience, DataMaster appears to overstate the duty cycle. Hard to understand how it does this, because its a simple calculation, made in the program, based on pulse width and RPM. Appears the program uses "base pulse width" for the calculation, and this may not represent the actual pulse width, after various correction factors have been applied.

What do your long term fuel corrections look like in DataMaster? Do you have a data log corresponding to the dyno pull?

Announcement

LT1 swap dyno question

LT1 swap dyno question

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment