Head and Cam Swap, 82 CFI



Re: Head and Cam Swap, 82 CFI

Postby Indycars » February 15th, 2015, 2:15 pm


Have you checked the intensity of the spark? Should jump 1/4" to 1/2" in free
air and be blue. Should also hear a pretty loud snap when the spark jumps.

It would also be a good idea to post some clear pictures with the plugs numbered
as to cylinder.

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Re: Head and Cam Swap, 82 CFI

Postby Drawmain » February 15th, 2015, 6:55 pm

Yeah spark is loud and blue, lol. I'll get some pics up soon. These plugs haven't been run long at all. I haven't driven the car in a couple of weeks due to the issues with timing and fuel. The new system is supposed to get here wednesday, currently the interior is gutted and the computer is removed in preparation for installing the new ECM and ESC. "While I was at it" syndrome hit and I have ordered a few parts for the interior that I have been meaning to get to, but never have, so I'm loading up my wagon. Today I repaired the seat tracks that have been sticking and did a lot of cleaning while I had the seats out. Don't want to waste time while waiting for everything to arrive so I've been doing little jobs to keep my interest up. Before these issues hit at the beginning of January, the car ran great. Once I get this sorted out it will run great again AND be tunable. The new ECM was in the long range plans anyway, the timetable just got moved up a bit.
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Re: Head and Cam Swap, 82 CFI

Postby Drawmain » February 15th, 2015, 6:57 pm

87vette81big wrote:If it was me Drawman the Champions 12's would go back in.
20 gallons of Aviation 100LL in the tank.
Or 110 motor octane race gas.

:mrgreen:



I can do the Champions easy enough, but the race gas may be a little harder to obtain, lol.
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Re: Head and Cam Swap, 82 CFI

Postby Drawmain » March 1st, 2015, 8:56 pm

Update:

I got the EBL Locker system installed. It wasn't hard at all to wire up and flash. Did a few runs and ran what is called "VE Learn" to help trim up the fuel curve. I was still having the same issue as before, but not nearly as bad. Problem was, it only cleared up to a point instead of tuning all the way out. So I went and did a 10 min drive and datalogged it. The EBL software lets you playback datalogs in real time through the software. Timing was good, wasn't jumping around all over like it was, knock counts were much much lower, and none at idle and cruise, just at high MAP (over 80 Kpa) and WOT pulls. So naturally I start thinking fuel again. Pressure checked out okay at idle, but I was wondering if the pump was keeping up. 13 psi shouldn't be hard for a TPI pump to maintain, but ya never know...

I have two sets of spare injectors that I've cleaned and kept just in case. I wanted to eliminate the injectors as a cause, and it was a free test, so I pulled out the 6 month old injectors and put in a set of GM/Rochester original equipment injectors instead. The 6 month old injectors were still shiny, the older ones were clean, but not as shiny, lol. I lubed up the o-rings and installed the older injectors. I found the issue. Bad injectors. What little knock I was still getting is all but gone, last knock count was under 80. I did more "VE Learn" rides and watched the computer pull back fuel that had been added in earlier runs. NO stumbles, NO knock, NO WOT bogging. The fuel curve looks a lot better now, I had a few cells that were up to 100%, which is not a good thing, now all the cells are back to more sane settings. Now that I have this issue (hopefully) worked out, I can start refining the tune, work on the spark and AE tables as I learn what the engine wants. On the last ride estimated MPG was around 28/29 at 65 in 4th. Not too bad. I'm just getting started with tuning, but I'd recommend this EBL for anyone that wants to keep a CFI motor and still have the option to tune the motor.
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Re: Head and Cam Swap, 82 CFI

Postby 87vette81big » March 1st, 2015, 9:16 pm

454 BBC TBI injectors 1987-1995 vintage are supposed to fit all CFI Engines Drawman.
Larger #'s per hour rating.
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Re: Head and Cam Swap, 82 CFI

Postby 87vette81big » March 1st, 2015, 9:24 pm

Injector offset time.
Does the EBL Cover it ?
All fuel injectors continue to flow fuel after solenoid cutoff current.
Its in Milliseconds time on a paper graph.
Not all aftermarket replacement injectors are the same.
None ever advertise very important injector offset time.
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Re: Head and Cam Swap, 82 CFI

Postby Drawmain » March 1st, 2015, 11:15 pm

EBL I think does cover injector offset time. Stock injectors on the CFI are different flow rates depending on position. The Front Injector is 68 lb/hr and the rear one is 67 lbs/hr. That's at 13 psi, higher pressure of course yields more flow. I need to research using the 454 injectors, since they would be the same flow rate on each side, it may require parallel plumbing with an external FPR. I'm not sure how much difference the 1 lb/hr between the injectors makes, but the engineers at GM had their reasons I suppose. I've heard it was done to compensate for the FPR being in the rear TB.

Now that I have the ability to tune, lots of avenues for upgrades are possible. It's never gonna be a fire-breather like a certain 70 T/A, but it'll get where I need it to get and now I can compensate some for today's less than perfect fuels. The 454 injectors sound fun :)
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Re: Head and Cam Swap, 82 CFI

Postby Drawmain » March 2nd, 2015, 12:32 am

I just looked in the tuning parameters and there is an injector compensation offset table. It is set dependent on the voltage to the injector. I don't know the specs of the injectors I have, so for now I'm leaving this alone. The injector part numbers are 5233775 on the front Injector, and 5233770 on the rear. I have the flow rates, just not the offset time.
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Re: Head and Cam Swap, 82 CFI

Postby 87vette81big » March 2nd, 2015, 11:21 am

There should be a Battery voltage compensating table too Drawman.
Once that is set & injector offset time you can tune away.
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Re: Head and Cam Swap, 82 CFI

Postby 87vette81big » March 2nd, 2015, 11:31 am

Yeah Drawman.
Its a Drag Race Year 2015.
Some cars are more natural to Race to 10.5- 9.0 ET 1/4 Mile.
Since $$$ has been a factor since 2008 for the little guys I have come to the conclusion Any Corvette is not a viable choice for the masses.
Best to start with a Solid axle car to begin with.
Pontiacs my choice in 2015.
Haven't lost my love affair with Vettes.
Just most of the owners outside of a handfull I have helped like You.
Drag Racing proves all.
Most Vettes will be blown away by Hellcats & SRT Viper T/A.
Don't stand a chance.
I tried helping.
Time to work on my own .
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Re: Head and Cam Swap, 82 CFI

Postby Drawmain » March 2nd, 2015, 8:01 pm

I sure appreciated your help, thanks! Trying to decide what rear gears to put in next, thinking 3:55 or 3:73.
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Re: Head and Cam Swap, 82 CFI

Postby 87vette81big » March 2nd, 2015, 8:31 pm

Drawmain wrote:I sure appreciated your help, thanks! Trying to decide what rear gears to put in next, thinking 3:55 or 3:73.

Probably 3.55 be a nice match with your 355 CFI and 700R4 Trans and rear tires used.
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Re: Head and Cam Swap, 82 CFI

Postby Indycars » March 2nd, 2015, 9:28 pm

Drawmain wrote:I sure appreciated your help, thanks! Trying to decide what rear gears to put in next, thinking 3:55 or 3:73.

What RPM do you want to cruise at??? Or are you looking for something better for the 1/4 mile???

Why not take a look at this and see what seems the best.

viewtopic.php?f=99&t=3355
viewtopic.php?f=99&t=5665

Rick
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- Check Out My Dart SHP Engine Project: viewtopic.php?f=69&t=3814
- Need a Dynamic Compression Ratio Calculator: viewtopic.php?f=99&t=4458
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Re: Head and Cam Swap, 82 CFI

Postby Drawmain » March 2nd, 2015, 10:54 pm

Thanks for the replies. It looks like based on Indycar's charts and Brian's recommendation, the 3.55's will work the best for me. I won't be drag racing the car and the RPM in 4th with the converter locked for 27" tires looks like it will be a nice trade off with the launch in 1st. Indy, those excel charts are gold! I knew there was a big rpm drop with the 700r4, but your graphs show it well. My car currently has a 2.87 rear, and while cruising at 2000 rpm at 80 mph is nice on the interstate, the rpms get too low for me at the lower speeds I find myself running on the roads I'm on the most. I'm also looking to go to a manual transmission possibly in year or two. I think the 3.55 would be better for that eventuality as well.
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Re: Head and Cam Swap, 82 CFI

Postby 87vette81big » March 3rd, 2015, 2:29 am

Drawmain wrote:Thanks for the replies. It looks like based on Indycar's charts and Brian's recommendation, the 3.55's will work the best for me. I won't be drag racing the car and the RPM in 4th with the converter locked for 27" tires looks like it will be a nice trade off with the launch in 1st. Indy, those excel charts are gold! I knew there was a big rpm drop with the 700r4, but your graphs show it well. My car currently has a 2.87 rear, and while cruising at 2000 rpm at 80 mph is nice on the interstate, the rpms get too low for me at the lower speeds I find myself running on the roads I'm on the most. I'm also looking to go to a manual transmission possibly in year or two. I think the 3.55 would be better for that eventuality as well.

Unless your road racing or competitive drag racing and prefer a stickshift there is really no need to spend $5 k on a manual trans conversion.
You still have a 12- 11 second 1/4 car.

None aftermarket have ever matched the precision and gear ratio spread of the Muncie M-20-21 &M22 along with superior race strength.
Eat up only 15-20 Hp.
Drag race overdrive is not used.
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Re: Head and Cam Swap, 82 CFI

Postby 87vette81big » March 3rd, 2015, 2:42 am

700R4 is a nice match for the CFI Engine.
Cost to build is low compared to 4L80E with high stall converter.
Lower cost than 200R4.
700R4 is real efficient .

MPG #'S prove it.
1st gear of 3.06 gives you an edge over higher HP cars from a holeshot launch at the stoplight.
Beat or at least keep up with 500 Hp cars on 1-2 shift.
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