My '87 3.4 with MAF project

[pooder]

UPDATE 03/2/2015: Before and after dyno results are now in! See post #63:


My story: I bought my ’87 911 with 72K miles 4 years ago. It was an effort to replicate as closely as possible what I had bought new in 1986 and had regretted ever since selling it. After 3 years of ownership of the ’87, it now had 86k miles and needed valve guides as it was burning 1 qt oil/300 miles, and I had moved to Breckenridge, CO at 9600 ft and it needed more power. So upon the recommendation of Grady Clay I took the car to Greg Johnson at Eurosport Ltd in Denver and came up with the plan to make it a 3.4 with new Mahle Max Moritz type P+C’s, 964 cams, honed intake and SSI’s with a Dansk sport muffler. (I am aware of the opinions regarding SSI’s in a 3.4 but this was a reasoned decision.) This car is intended to be a daily driver with plans for extended touring, and therefore I was focused primarily on improving performance in the middle of the RPM range. The challenge for this car was optimizing tuning of the AF ratios for the intended operating range of 10,000 ft to sea level. If tuned for optimal performance in Breckenridge, then it would become dangerously lean at sea level and I had accepted the fact any tuning effort would be a compromise.

The car had an Autothority chip from a PO and my search to locate a stock chip for the baseline dyno led me to Sal Carceller. Sal is an active member of this forum and is a software engineer who was able to provide me with a stock ’89 chip; but more importantly, once he heard about my situation, he told me about the MAF he has developed over the past several years for the 3.2. As I understand it, he has decoded the entire chip in the 3.2 DME unit and has rewritten the code in the chip to allow full integration of a modern MAF with the DME unit as opposed to having a MAF pretend that it’s an AFM. Talking with Sal I was impressed, as was my engine builder, with the depth of his knowledge and the development effort he has put into this project. Although a fully integrated MAF will provide incremental benefit to any motor, for my situation this was especially true.

As the project stands right now, the car has been dyno’ed with the stock chip and stock AFM and is making a healthy 234 HP and 220 ft-lbs at the rear wheels on 91 octane pump gas in Denver (see dyno graph below). The MAF system intended for my car has been tested by Sal on his own ’84 M491 Cab and I am now awaiting the arrival of the MAF with its unique chip installed in a modified DME along with new Bosch injectors whose specific parameters have also been programmed into the chip. The DME’s chip will reflect the modifications that have been made to my motor. I expect to receive the MAF this week and will provide update after it is installed and dyno’ed.

This is the WOT dyno run with stock chip and AFM. The "fuel pressure" line is actually the intake vacuum.


This is an picture of the MAF that is being shipped.

[ischmitz]

Yes, Sal knows "a thing or two" when it comes to the 3.2 DME..... Pretty cool setup he developed and with his understanding of the Bosch code you found the best. He did decode the entire 3.2 machine code.

Keep us posted once you get it installed,
Ingo

[gliding_serpent]

You numbers and modifications certinally peak my interest from our prior discussions. Dynos vary, but your numbers do not seem unrealistic given the intake, displacement, and compression ratio upgrades. I am just impressed that you got those numbers pre chip tuning. Mind you, your baseline afr's look good. The "ssi's are too small in a 3.2" folks might have their eyes opened also. Subscribed.

I have ssi's and a m+k 2:1 waiting to go on my car. I planned to cut my airbox cup style (po drilled it), and i plan on going with a 964 cam. With a steve wong stage 2 chip tuned the the setup, i estimate 250hp at the crank. Pending inspection of my pistons, it would be hard not to go 3.4 (but i am unsure of the hassle of a twin plug, thus my interest in your single plug setup). I am actually most interested in replicating your current setup pre MAF/injectors.

You are already at near 270hp at the crank. I bet you will be pushing near 300hp all said and done.

I am madly researching the topic, but can you get je pistons with the single plug design? Or is that a mahle only thing (thus requiring the buying of cylinders also).

[scarceller]

I think the SAE conversion on this dyno is a tad optimistic and I don't put all that much faith in the numbers themselves. This dyno shop is located at 5000 foot elevation and the dyno does SAE corrections for the given atmospheric conditions. What I really look at is just the before and after numbers as that's what's most important. I suspect that if the engine was dynoed at sea level the numbers may be slightly lower but who knows. Given the 234HP at the wheels you are correct that it's about 270HP at the crank! I just don't think this 3.4L is pushing that much power with a stock chip. As I said we'll see what happens once the MAF goes in. The other interesting item is that we have almost -2lbs vacuum at WOT in the high RPM range, this is most likely the stock AFM causing a restriction and pressure drop across it.

You mention drilling your air box, DON'T do it. You need to prove you have a restriction first. Monitor intake vacuum during a WOT run and you'll know for sure. I don't think the air box is the issue, I suspect the AFM is the source of any restriction.

Originally Posted by gliding_serpent

You numbers and modifications certinally peak my interest from our prior discussions. Dynos vary, but your numbers do not seem unrealistic given the intake, displacement, and compression ratio upgrades. I am just impressed that you got those numbers pre chip tuning. Mind you, your baseline afr's look good. The "ssi's are too small in a 3.2" folks might have their eyes opened also. Subscribed.

I have ssi's and a m+k 2:1 waiting to go on my car. I planned to cut my airbox cup style (po drilled it), and i plan on going with a 964 cam. With a steve wong stage 2 chip tuned the the setup, i estimate 250hp at the crank. Pending inspection of my pistons, it would be hard not to go 3.4 (but i am unsure of the hassle of a twin plug, thus my interest in your single plug setup). I am actually most interested in replicating your current setup pre MAF/injectors.

You are already at near 270hp at the crank. I bet you will be pushing near 300hp all said and done.

I am madly researching the topic, but can you get je pistons with the single plug design? Or is that a mahle only thing (thus requiring the buying of cylinders also).

[pooder]

I am no expert, but I would think that with JE pistons and single plug you might be limited to 9.5CR. My initial approach after doing my research was to bore my Alusil cylinders to 98 and replate them with Nikasil and use JE 10.5 pistons with a dual plug setup. I then listened to my engine builder and followed his advice down the path that I took. I also was told that the SSI's were too small. My research on this revealed that mid range torque is associated with high velocity flow (smaller, longer primaries), and high RPM power requires maximal flow (larger, shorter primaries), and I needed heat. Again I am no expert. My goal was drivability rather than chasing highest numbers.

[pooder]

My runs with and without the airbox were identical for both the intake vacuum and torque, HP. I believe that Sal is correct about the AFM being the point of restriction.

[ischmitz]

Drilling the airbox only increases the intake sound. While that might fool the seat dyno it doesn't do much for real power. There was an option called the Motorsound package for the 993 with a different air box and some exhaust mods.

[3literpwr]

This cat as well as a number of others have been running higher CR's with single plug with success. Granted most are overseas and have access to higher octane fuel. Not saying its the best option, but people are doing it.

https://project911sc.wordpress.com/category/engine/

[scarceller]

This motor is a 3.4L with 10:1 compression and single plug. Given that most of the driving will be at 5000 foot and above elevations it should do well. We can already see that it does well at 5000' at the dyno.

[gliding_serpent]

The prior owner already drilled my airbox.

This is a post where steve wong dynos stock 3.2 cars with and without the intake cover (cup style) and exhaust. Note: chip tuned to balance afr ratios. I think that is key for gains.

3.2 Dyno Tests: Airboxes and Mufflers

Seems there is something to be gained. My understanding is that the gain is larger with a higher hp engine (naturally needing more air). I also understand that the maf is another limiting factor. This is a good transition into the benefits of extrude hone. I digest intake restrictions as coming from multiple areas if you simplify it. Improving one area helps, assuming your air pump/engine actually needs that extra air.

My local tuning expertise is limited for these cars, so i am looking to copy a "mix" that balances power, cost, simplicity and durability.

[gliding_serpent]

Pooder, I am learning as we go here, but did you go 10:1 because at higher altitude (lower pressure), this might equate to 9.5:1 plus or minus at a lower altitude (armchair math here)... Thus being safe with 91 octaine?

[pooder]

The MM Mahles are sold as 9.8CR. After the headwork was done, the actual CR by volumetric measurement was 10.0. It was what it was and there was no move to lower it. I have never understood this caution about CR >10, in as far as I can tell Euro 3.2's function well here with their allegedly 10.3 CR.

[scarceller]

My personal engine is a 3.2L Euro at 10.3:1 and it runs very happily here at sea level with single plug. I see no reason why the 3.4L would require dual plug setup although dual plug would benefit by a few extra HP but that does not mean single plug won't work with hi-comp.

[gliding_serpent]

I Guess it comes down to octane, how agressive you want to advance your timing, and your level of risk acceptance for detonation.

We only have 91 octane. I will mix in airplane fuel for track use (o2 sensor delete), but i want to build for durability and the lowest common denominator.

[Jcslocum]

What do you think the cost of this MAF setup will be???

We're in the twin plug 3.4 camp over here :-) But know the current system is a bit of a bottle neck.

[pooder]

The price of Sal's MAF system, inclusive of the modified DME box (no exchange needed), the 6 new fuel injectors and the MAF unit is $2200. However it would be best to contact Sal directly to confirm.

[scarceller]

Originally Posted by pooder

The price of Sal's MAF system, inclusive of the modified DME box (no exchange needed), the 6 new fuel injectors and the MAF unit is $2200. However it would be best to contact Sal directly to confirm.

Correct, but the system is NOT a do it yourself (YET) I'm only doing these through very experienced engine builders that have years of experience building and working on these motors. The only ones done so far I've done locally myself and I'm just starting to reach out to some select P shops. I simply want the system done correctly and it requires very rigorous review of an engine's current state before I ever install the product. You can't tune around engine issues. 'pooder' was a great choice for the MAF for several reasons: 1) his engine is a fresh rebuild with no known issues. 2) the MAF fits his needs for elevation changes he intends to drive in. 3) most important he has a very experienced mechanic doing this install with my assistance.

At this time the system is not available as do it yourself, I'm still doing shake down on the code and more refinements.

And as mentioned it's not just a MAF it's an entire system that includes the MAF & Air Cleaner, set of 6 injectors and a special DME (can oly be used with this MAF). Just a set of new stock injectors will set you back $700 and a DME another $1000.00! This is an integrated system and you don't cut a single factory wire or harness! Take out your injectors, your DME and AFM + Air Box set them aside and install my kit. Plug and play and you can go back to stock at anytime, just put back the original parts.

[pooder]

A photo of Sal Carceller's complete MAF system before it was put in the box and shipped to me today

[Jcslocum]

I'm looking forward to updates and results!!

[scarceller]

Originally Posted by Jcslocum

What do you think the cost of this MAF setup will be???

We're in the twin plug 3.4 camp over here :-) But know the current system is a bit of a bottle neck.

Jon,

For your twin plug setup you'd use the same MAF setup but it would have reduced ignition maps and I would recommend starting with ignition values from the factory 964 RS engine. We would then fine tune them from that point. Basically this would be the same exact S-CAR MAF but with a custom chip to meet your needs.