396 with Miniram my sig says in a 6 speed Vette. 30 pound injectors, 165 ECM and chip by me. Ported AFR 195 heads, TPIS headers, 10.75:1 compression, hi flow cat, Corsa mufflers, comp cams hydraulic roller 220/229 duration, .550 lift. In other words all the goodies. On a Dynojet yesterday my results were 327 RWHP and 377 RWTQ. Question:

1. I'm in the process of converting to a 7730. Can the MAF be that big a restriction? I feel like I'm missing 70 horsepower at the wheels! I can kick myself now for not paying the extra for the wide band O2 hook up at the dyno. All I can say is that there was black smoke coming out of the tailpipes on occasion while on the dyno at high RPM's.

Similar cars with 396's on the same dyno had 400 RWHP but they were LT1's. Anyway, looking for some comments.

Jason



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89 Six Speed FX3 coupe
More Performance 396cid specs:
Callies 4340 crank 3.875 stroke
Lunati Pro-Mod 5.85" rods
SRP Pistons 14cc dish
Comp Cams Custom cam 550 lift 220/229 duration
10.8:1 compression
AFR 195 competition ported heads
Miniram and TPIS 1 3/4" headers

 

That sounds like it would be a little closer to my tune port set up with the 406 jason. My buddies are still trying to talk me into the speedpro unit.
Z-BOSS

 

Sounds like you were running way too rich, which is costing you a bunch of power. Since the MiniRam is very similar to the LT1 intake, you should be making similar amounts of power, although your 396 could stand a lot more cam like the CompCams 306 or one from the Xtreme line (maybe 230/236 duration).

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Greg Westphal
'87 IROC 305TPI/A4

 

I wanted to stay with a cam that had a chance of passing smog in PA. I know I don't have EGR but I probably can get past that. I am running 30 pound injectors with an injector constant of 33. PE vs RPM is zero in the last four places in the table.

Jason

------------------
89 Six Speed FX3 coupe
More Performance 396cid specs:
Callies 4340 crank 3.875 stroke
Lunati Pro-Mod 5.85" rods
SRP Pistons 14cc dish
Comp Cams Custom cam 550 lift 220/229 duration
10.8:1 compression
AFR 195 competition ported heads
Miniram and TPIS 1 3/4" headers

 

I know guys have passed the IM240 test (roller test) in Maryland with the 230/236 cam, although having a 114-degree LSA helps compared to the usual 112 LSA. With the 30# injectors, you might need to subtract fuel from the upper RPMs if you're running that rich. The first thing you need to do is get back on the dyno with that WB O2 hooked up to see how things look. A scan tool to monitor knock retard and such would be a good idea too.

------------------
Greg Westphal
'87 IROC 305TPI/A4

 

Greg is on the money. I see 2 things that are costing you power...
1) Cam
2) Tuning

That cam is 'hella small' for that engine. You can add about 9 degrees of duration for every 50 cubes. IMHO, you should be running a 236/245 cam in that big bad 396. Heck, if I am running a 230/245 cam in my 350 then you can just as easily run a 236/245 cam in your 396. That is 16 degrees more duration then what you are currently running. That is A LOT!

Tuning ... black = rich. You need to lean out the WOT PE % Change to AFR vs RPM table. But, more importantly (and you already know this), you need to get a wide band on it to see just where you currently are.

IMHO - go MAP/730. That engine is going to need a ****load of air and the MAF WILL BE a MAJOR restriction in your case.

Tim

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TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's with bigger cam, bigger stall, and bigger exhaust.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

I believe that if you have the money, go with a speed pro with a wide band. It made a difference of night and day in my car. And it doesnt take a month to get it dialed in.

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87z 383,afr 190's, comp hyd roller(242/248-.540/.562,114 sep),Ported and polished mini ram, 30lb inj, 3.42 gears, tremec 5spd, , 1,3/4" slp headers, speed pro bank to bank-wb02.
"Just remember children, no man can beat you once youv'e found the cliterous." 'chef'

 

Thanks guys for your replies. First off of the cam. I chose that cam because Mike Oshuka from MORE Performance http:\\www.moreperformanceinc.com
highly suggested that cam for my motor. This is based on his many hours of dyno time with albeit mostly 396 LT1's and LT4's. It is his custom grind made by Comp cams. This cam in 396 LT motors makes 500HP on the engine dyno (no alternator, ps pump, etc) on a consistant basis with CNC ported stock heads that supposedly do not flow as much as mine. Supposedly. With the next bigger cam, he has seen 535 HP. I know a guy with a LT4 that was build by MORE with my cam and his motor dynoed at 494HP on the stand. I did not want a real lumpety, lump idle and I like I said above, I wanted a chance at passing emmissions. Maybe in hindsight it is too small but I am almost 70-90 HP short of my expected goal. Right now I have 380-390 HP at the flywheel depending on what conversion I use.

Second on the WOT fuel curve. I feel that this is where most of my power is hiding. My PE vs RPM table looks like this:

11.718
11.718
11.718
11.718
2.343
2.343
6.25
6.25
2.343
-3.125
-3.125
0
0
0
0
0
0

I have a bin file from a VERY well known tuner (and expensive and no its not TPIS or LPE or Ed Wright ) that is for a Minirammed vette 350 with 24 pound injectors and their PE vs RPM table looks like this:

11.718
11.718
6.25
6.25
0
0
6.25
6.25
7.031
1.562
4.678
-11.718
-18.75
-16.406
-18.75
-10.56
6.25

Coolant tables are both stock. So you can see they are pulling out a ton of fuel. I did an experiment the other day before the dyno run and changed the 0 values from 4500 RPM up to +3. At WOT and when I reached that rpm, the car just bogged and went nowhere. I assume the injectors went stadic. I did not have diacom running at the time. So I assume (yes, yes I know about assuming) that I am pig rich in the upper RPM's. If you look at my HP dyno curve, it starts out nicely and then starts to flatten a litte near 4000 PRM and does not climb as fast to 6000. Torque starts out flat as a table and then falls off where the horsepower starts to flatten again at 4000.

As for speed density, I gave myself the green light. I bought a junk 165 for the header, a 7730 ECM and V8 memcal and the 7730 plugs with pigtails to pin to the 165 header from the junk unit. I even have a way to use the exsisting knock sensor by addign a 4.3K resistor thanks to Don Roudolph another 89 vette owner that did the conversion.

Get ready guys, I'll have lots of questions on speed density and the archives are only so big. Trax's P730 article was awesome and I truly appreciate his efforts. I feel I have a confident understanding on how to tune a speed density system now. Most of the things I learned on a 165 will help with the speed density tuning. Another nice thing is that while on the dyno, I can run the car with the MAF in place and then yank it off to try and prove once and for all how much a restriciton it really is.

Thanks again.

Jason

------------------
89 Six Speed FX3 coupe
More Performance 396cid specs:
Callies 4340 crank 3.875 stroke
Lunati Pro-Mod 5.85" rods
SRP Pistons 14cc dish
Comp Cams Custom cam 550 lift 220/229 duration
10.8:1 compression
AFR 195 competition ported heads
Miniram and TPIS 1 3/4" headers

 

I plugged in the leaner PE vs RPM table and it seemed to have helped. O2 volts were high .800 mv range at 5400 RPM. I know that is not accurate but before they were mid .900 mv range. I want to try and get it close before I go back and spend the money on the wide band O2.