1988 4.9 c6 turbo build, megasquirt or quarterhorse?

T

tdale2144

New member
Hey all,
I am in the process of planning my turbo 4.9l build and had some questions! I plan on running e85 and converting from speed density to MAF but was wondering if its easier/more cost effective to buy a 1996 4.9l ecu/maf and wire harness or am I able to just swap a 351 MAF and wire up a megasquirt/Pimpx unit? Any input would be greatly appreciated! The truck has been in my family since new and decided i should spend some money to make it fun and have a reason to keep it around since I will never sell it!
 

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My opinions only.

Wiring on Ford EFi's for 88s is sub par, so updating to another MAF EECIV might require as much work as a MegaSquirt. I'd keep your stock emissions stuff intact, and add a MegaSquirt. Keep your stock EECIV computer, and allow it to run the EGR and AIR and just use the MegaSquirt for key fuel, ignition and MAF sensor system changes. A GM MAP sensor and MAF sensor conversion are what the plug and play uses, so you can split the stock computer and use the PNP as an auxiliary fuel and ignition and MAF system.

Ford for a few years used a break out box attachment in the days before the 1991 truck's live data streaming. Crane Interceptor, Extreme Edge, Actron Break-out Box. They allow you to double tie the 60 pin connector. That allows you to keep the stock wiring pinouts, but you can live data feed via TunerStudio from MS PNP. In a similar way, Quarterhorse uses a J3 port, a very good system, but for 200 bucks you can multiplex your EECIV pinouts to the critical Malfunction indicator light parts, and have the MegaSquirt take over fuel delivery, ignition and boost.

I'm giving you advice, not telling you what thou shalt do. If you truck was a 95 or 96, I'd be suggesting the EECIV or V.


How it works for emissions and simplicity varies a lot. The blended approach then allows you to fix the two biggest problems with an early EECIV...they don't like any changes to the speed Density program, they have to many problems updating to MAF because if the transfer function, and the stock injection and ignition system isn't mapped for updates.

Your going to be using much better injectors, and the air pump can be used as šŸœ i lag. The šŸ±'s can stay. The high low fuel pump system can stay stock with its normal pressures boosted, EGR is a proven closed loop knock reducer, so stock wiring can feed through the stock TPS and MAP signals. MegaSquirt uses a recommended sensor type and if turbo, MAF is better.

Gotta say, any changes from the stock wiring or fuel delivery on any 1989 US EECIV vehicle is a guaranteed Major Project Rewire and Pumps and Hose rework. I'd buy the two pumps, and keep all the crash switch and pickups and returns stock, but redo the lines with better quality AN fittings. You want to keep the power steering, air con, the KOEO/KOER fault coding, and have no problems with any of the annual inspection or licencing.

With the money saved on not doing a full rewire, spend big on a much better cam reprofile by Schneider and some forged pistons and better conrods. And don't be afraid to get the head ported and the valve train updated to suit a 525 thou cam lift.
 
awesome i appreciate the input! i did delete the smog pump already unfortunately as it seized up but i still have the majority of the EGR components in a box.
 
tdale2144 said:
yes will be running e85 only
Click to expand...
The EGR system reduces NOx emissions and increases fuel mileage by allowing leaner fuel mixture before detonation.
Both benefits are because of lower cylinder temps due to oxygen reduction by EGR.
However, E85 has lower NOx tailpipe emissions than E10.

Secondly, if you are doing a performance build with a higher duration cam profile, the increased overlap duration introduces EGR.
IMO the EGR system will no longer have enough benefit with E85 to keep in operation.

Why do you feel the need to use a MAF based EFI system?

How much boost are you looking at using?
What rpm range do you want the power band to have?
 
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Planning on keeping the motor essentially stock for right now but will be looking for another block to build in the future. I have more experience with newer cars and speed density is a little foreign to me but i understand the concept, and figured if im adding boost it would make more since to switch to a MAF for better tuning. Planning on 8-10PSI with a gt3582 turbo that i have from a different build.
 
A GT3582 with a 61mm compressor inducer will give you a strong power band from 2500 to 5500 rpm.
It will require a fully ported, big valve head to do so.
The Promaxx CNC ported, big valve head has the unshrouded combustion chambers and would be recommended for this project.

I'm used to seeing the ignition timing tables based on MAP especially under boost where the timing is reduced quickly above 100 kPa.
How did you control timing previously while using a MAF sensor?
 
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I still need to do some research but i believe i can disconnect the timing module (not sure what it is actually called) to lock the timing and was hoping that would be enough for this low boost/power. Unfortunately I have more experience building/turboing with newer mustangs and corvettes with lots of aftermarket support so this whole tuning process will be a learning curve for me. So If i go megasquirt as Xctasy said I can plumb in a MAP sensor and wire it to the megasquirt and tune off of that?
 
The MegaSquirt uses common GM sensors. It can take a Four Bar sensor, and plot ignition under boost retard, but it's mapped for all conditions under open loop via the Wide Band O2 sensor. Off boost or under closed loop, the stock EECIV can run under the MegaSquirts fuel control strategy. This is just like using the MS3 PNP as the Auto Controls Auxhilary Computer in early Turbo GNXs, Alfa Romeo 2.5GTVs, Callaway Corvettes, and the 1983-1992 AIT Falcon 4.1 and 3.9 liter Multipoint EFi turbos.
 
Auxhilary wiring the MS3 PNP is just like adding an Impco Liquid Propane Gas "Command Module" on to a CARB approved Feedback Carb or TBi or port EFi or Direct Injection engine. Stock Federal Motor Vehicle approved wiring, with the open loop modified for when operating on a different fuel.

To comply with the letter of the law, use all the stock systems so your not removing any emissions part, then splice in to operate under load, open loop commands via the PNP MS3.
 
So I am looking to buy the MS3 megasquirt and have been looking on diyautotune.com , I believe MS330-K will work for me but can anyone confirm? Appreciate the help as I know this is basic stuff to most of you but this will be my first non OBD2 project.
 
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