I'm a beginner at this so basically I don't know most of the specs of the l98, but I want to set it up in desktop dyno to estimate and work on a good combo. Can you guys help me out? I'm finding it difficult to find all of these data on the boards. Here are the things I need to set it up:

1) Extensive flow numbers for the stock iron heads to put in the "custom flow" settings (or an accurate Airflow file)

2) Intake and Exhaust port sizes for the heads

3) Stock compression ratio

4) Flow numbers for the intake system (like what cfm@inHg)

5) All the specs for the '92 l98 cam (I know they differed over the years, I need the '92) or the accurate cam file for DD if possible.

Even if you know a few or only one of these things, it'll help! Thanks!

 

1:

Lift Intake Exhaust
.1 53.9 41.6
.2 111.2 95.2
.3 157.3 112.4
.4 182.0 116.6
.5 192.0 116.9
.6 193.6 117.6


2: 1.94 intake 1.5 exhaust

3: 9.3 stock compression ratio

4: This is the one I don't know for sure, and the one I'm having trouble modelling in DD2000

5: Ok, here are the specs that are accurate for my 88 GTA. The 92s I don't believe were that far off...

These are @0.05
duration 207/213
lift .415/.430
117 lsa

 

Funny thing, Here on the board the specs for a 92 L98 is 9.3-1, but in my chiltons book it says 9.8-1. I would really like to know which is right. I have seen it posted both ways in different places.

I know the late 80's L98 have 9.3-1 but like I said in the chiltons manual it had 9.8-1.

Which is right?

 

with that setup I'm getting 228 hp at 3500, 4000 rpm just wanted to know if i should mess with the timing in D2000. I'm using 780cfm because this is what i've heard stock TB's flow but i guess to be you also use 560 or 530 around what a stock maf flows either way it doesn't make a large difference, just shows how useless a bigger throttle body is.

I don't know if it was you jraskell who did the flowtesting, but post the lightly ported flow numbers, it makes a huge difference. I was also wondering those numbers are from stock valves too, for the lightly ported and the stock.

 

Don't quote me but I think i remember reading somewhere that a stock tpi flows arround 300cfm?

Where the 87+ lifters hydraulic flat tappet or roller lifters? Because I though they were roller, but whenever I put that into DD2000 I get a whopping 384lb of torque, which seems to high. Putting it to hydraulic flat tappet gives me a more realistic 335lb. Im using l98 flow #'s, 9.3 comp ratio, 300cfm flow for tpi, and the cam data off of thirdgen

 

Stock Tuned Port flow is more like 525 or 550 cfm. Those torque figures probably came out way too high because the program is figuring them with solid roller lifters. The roller option does not specify solid or hydraulic.

 

What should I use for Pressure Drop in H2O in the custom flow settings for the heads?

 

Oh and what are the correct numbers for the options at the bottom under "Camshaft"? I don't even know what these things are:

IVO
EVO
IVC
EVC

 

Pressure drop should be fine at 25. IVO/IVC & EVO/EVC columns are automatically adjusted when the other cam specs are entered. No need to change them when entering stock cam specs.

 

I'm having trouble setting up the cam right - LSA is not an option, but what are the correct numbers for Lobe Center Angle and Intake Centerline?

 

anybody?

 

All cam specs can be entered by clicking the cam math button on the menu bar. It will open a window for entering all info.