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454 swap....running good, looking at on board air

well I just got the prom and it is a hypertec thermomaster. I thought that it was going to be a stock one.

The fuel pump is getting weak in this burb, anyone have a pump to reccomend for performance? I am hoping to find one that is parts store available. and I plan on running 15 psi.
 
black dawg said:
well I just got the prom and it is a hypertec thermomaster. I thought that it was going to be a stock one.

The fuel pump is getting weak in this burb, anyone have a pump to reccomend for performance? I am hoping to find one that is parts store available. and I plan on running 15 psi.
Click to expand...

One option would be to add the Knock Sensor and ESC Module later if you want. Another option if you want, is to send me the Hypertec chip and I can read the chip for you. Send me a PM if you need know where to ship the Hypertech chip.

I've heard, but have not actually used, a 1999 C/K 454 MPFI Vortec fuel pump is a low cost upgrade?

dave w
 
dave w said:
One option would be to add the Knock Sensor and ESC Module later if you want. Another option if you want, is to send me the Hypertec chip and I can read the chip for you. Send me a PM if you need know where to ship the Hypertech chip.

I've heard, but have not actually used, a 1999 C/K 454 MPFI Vortec fuel pump is a low cost upgrade?

dave w
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Thanks for the offer, I might take you up on that. Do you have a preferance with or without esc?

I need to change this fuel pump soon, but wont have the 454 ready for a couple weeks, I wonder if the better fuel pump will cause any issues being run with the 350...... maybe it is too much for a stockish 454.
 
black dawg said:
Do you have a preferance with or without esc?
Click to expand...
If you use ESC then the ESC module and Knock Sensor are needed.

black dawg said:
I need to change this fuel pump soon, but wont have the 454 ready for a couple weeks, I wonder if the better fuel pump will cause any issues being run with the 350...... maybe it is too much for a stockish 454.
Click to expand...

I don't think the 350 TBI will have problems with the the upgraded fuel pump.

dave w
 
what I meant was do you prefer one set up with a knock sensor and esc or set up without.

and the fuel pump works ok with the tbi. It is slightly richer in open loop and wot feels flat. was .900 before wot, now is .950 wot.
 
black dawg said:
what I meant was do you prefer one set up with a knock sensor and esc or set up without.

and the fuel pump works ok with the tbi. It is slightly richer in open loop and wot feels flat. was .900 before wot, now is .950 wot.
Click to expand...

For a stock compression ratio engine, I'm OK without the ESC and Knock Sensor on a BBC. For a modified engine with more than 9:1 compression ratio, I would definitely use the ESC and Knock Sensor.

Not sure what the numbers .900 and .950 are from?:confused: I was thinking maybe the O2 sensor voltage?:dunno:

dave w
 
yea sorry, 900mv and 950mv. I realize narrow band o2 sensors arent the most accurate for this type of thing, but what voltage range should I be shooting for for sustained wot?
 
For a few seconds or less the WOT voltage of the O2 sensor will be in the 0.900 ~ 0.970 volt range. The MAP sensor / ECM should catch up and control the fuel after a few seconds.

dave w
 
I use the Walbro 225 for my vortec 454 in my 91 sub, and used it in my 350 before i swapped the 454 in. Just be ready to switch to a BBC regulator when you do the swap. In my personal opinion the 781s drop way more compression than the vortecs, and probably dont outflow them anyways. id use the vortecs if you have access to them. 15psi is a bit much for a stock 454 IMO, im using 14.5 in my vortec 454 with headers, intake and higher compression. mine runs at .800ishMV at full tilt and it seems pretty **** beautiful roastin 40s over
 
dave w said:
I agree with the roller cam. I would use a hydraulic roller lifter, not a mechanical lifter. I'd scrap the idea of a carb and TBI and use a Vortec 454 intake MPFI system. A few tweaks with a 93 ~ 95 TBI PCM and everything else bolts on to the older 454 heads.

dave w
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Late bloomer to this thread but I have to say this is cool Dave. More people should be looking into MPFI intakes on big blocks. I love the idea of running an L29 big block MPFI intake on the older TBI ECM’s. Not much more difficult to install than adding TBI to any big block actually. Basically batch fire the injectors in the L29 MPFI intake just like an overgrown TPI small block without the hassle of replacing the harness wiring adding a MAF, yada, yada, yada as if you were running this intake sequentially like it was intended in the ’96-’00 trucks. I sorta did that on a 454HO with a marine L29 MPFI intake a few years ago but used a RamJet 502 ECM and harness. The Ramjet 502 ECM batch fired the injectors on a basic speed density OBD1 platform as well. What a nightmare to tune though. Such a nightmare I gave up with trying to tune it where I was happy with the overall drivability and tossed an 8.1L running MAF in the truck. I’ll never recommend doing your own tuning! ECM tuning should be left to the experts to do, which Dave W sounds like just one of those guys. :waytogo:
 
Getting closer on this project, just wating on a few small parts. I am really curious to see how much better this runs than a stock tbi 454.

stock 74 454
781 heads
edelbrock performer intake
stock vortec 454 cam
headers.

will be towing 6-8k regularly
 
black dawg said:
Getting closer on this project, just wating on a few small parts. I am really curious to see how much better this runs than a stock tbi 454.

stock 74 454
781 heads
edelbrock performer intake
stock vortec 454 cam
headers.

will be towing 6-8k regularly
Click to expand...

That recipe sounds like it should run very well although I am not one for headers.
 
I was under the impression that headers help a big block alot.
Is mine mild enough to not benefit much?
 
They may. Over the years I’ve just gotten so sick and tired of dealing with overheated starter motors, exhaust leaks and burnt plug wires I’ll live with the power I may miss out on by not having headers. I run stock 7.4L manifolds on my 8.1L just for the reliability of them. It isn’t short on power by any means flowing through good ole manifolds.
 
If you use headers you will just have to tighten the header bolts often. Be sure to use the dead soft copper or alum gaskets and they wont blow out as often. The factory manifolds on BBCs are a nice bottleneck in the system. Just be sure to get a decent set of headers with a nice thick flange and youl be ok, just be sure to carry a 7/16 wrench in the truck to occasionally tighten them, or buy them fancy never come loose bolts. An fyi for the overheated starters is for a bit more money you can buy a factory GM gear reduction permanent magnet motor starter for i believe 97 and up that is smaller than the factory old style BBC starter and weighs about 10lbs less.
 
Well got it running this morning, and it runs really good. Ended up running manifolds on it as the header to starter clearance was almost nothing. These are decent headers, nice and heavy with thick flanges, but I think I will hold out for something better. Took it for a short drive (open manifolds) power seems OK, but didnt really beat on it with the open exhaust.

I wonder if that gr starter would give me enough clearance?
 
It's 93 and up, but I ran an 80s style because it was cheaper. with my hedmans on it it has good clearance and I have never burned up the starter in 8yrs. When it does go i will buy the newer style but I was young and dumb at the time and didn't want to wait the extra day to get it moving. If only we knew then what we knew now
 
Well I couldnt help myself, so I took it out for a test rod. Runs pretty good, ran it to 4500 and it was still pulling hard there. I am very happy with the power.
 
Anybody know of a good source that explains IAC function? I am having problems getting the idle speed to be consistent. I have done the min idle procedure, but sometimes it will still idle high, with iac counts in the 75 range.
 
black dawg said:
Anybody know of a good source that explains IAC function? I am having problems getting the idle speed to be consistent. I have done the min idle procedure, but sometimes it will still idle high, with iac counts in the 75 range.
Click to expand...

Maybe there is information on this website: http://www.gmcmidwestclassics.org/Web pages/Tuning the TBI.pdf

Changing the idle settings in the PROM chip is something I'm doing quite often for the PROM chips I help out with. I'm thinking the IAC counts are usually close to 10 ~ 20. Quite often, I'll just hook a scan tool and adjust the IAC steps without resetting the IAC as described in the minimum air setting procedure. Sometimes the fuel table needs to be calibrated (using a data log) to get the engine to idle correctly.

dave w
 
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