Anyone ever used Stack Injection ITB setup?

5F2010A9-E9A3-48C2-80AD-70FAFE7C05BE.png

As you can see, the fuel supply system would be very difficult to fit with this setup on this block if the injectors were located inside. Much easier on wider blocks.

Tim.
 
I hope that’s the current system, I upgraded about 10 years ago so apologies if it’s the earlier smaller TB system and not the stack injection setup.
As I said, I can’t check atm.

Tim.
 

Chris

Supporter
Thanks for that Tim, yeah I can see your point on that setup, it would be tight to internally mount those rails. Would be tricky to adjust the throttle system also if they were reversed.

I believe it probably going to go with an old IDA look system. Whether it’s from Jenvey, Jim Inglese or Borla (probably in that order)

I’ll hold out to see what Jenvey release this year, am in no rush for them. Just working out budgets etc :)
 

Dave Hood

Lifetime Supporter
I have Borla's set-up that looks closer to Webers than other fuel injection options. I'm using the FAST XFI Sportsman EFI system with it.


Borla.jpg
 

Jasper

Supporter
I have Borla's set-up that looks closer to Webers than other fuel injection options. I'm using the FAST XFI Sportsman EFI system with it.


View attachment 106655
That is very purdy! I actually sent Borla an email 2 weeks ago to ask about pricing for these 'Weber' look EFI stacks, but they never got back to me.
Can you comment on this maybe? Just the borla kit, the EFI-ECU and hardware I already have... Just wondering how much it will hurt..
 

Chris

Supporter
That is very purdy! I actually sent Borla an email 2 weeks ago to ask about pricing for these 'Weber' look EFI stacks, but they never got back to me.
Can you comment on this maybe? Just the borla kit, the EFI-ECU and hardware I already have... Just wondering how much it will hurt..
I saw on their website (eightstack.com which is now owned by Borla) that the prices start from $4900 so similar costs for the Weber look to the new age style.
 

Eric B

Eric
I saw on their website (eightstack.com which is now owned by Borla) that the prices start from $4900 so similar costs for the Weber look to the new age style.
I bought the 8-stack injection for a 496 FE motor about 10 years ago, and really had a problem getting it tuned for drivablility (WOT, start-up and idle were fine, just could not get the final tune correct) it now sits in my office
eight stack.jpg


I am going Monday to Dennis's to pick up my GT40 which has the Borla (MTW) system.
IMG_9876 small2.jpg


The main difference between the two styles is the MTW system has the injectors below the throttle plates, not above like the 8-stack.

Everyone I have spoken to has had great luck with the Borla MTW style. My experience with the 8-stack....not 100%

E
 

Glenn M

Supporter
I bought the 8-stack injection for a 496 FE motor about 10 years ago, and really had a problem getting it tuned for drivablility (WOT, start-up and idle were fine, just could not get the final tune correct)
I run the 8 stack/Borla "Weber" set up and have done for 10yrs. I don't have any issues with it at all. Infinitely superior to actual Webers for driveability IMHO. What makes you think it is not an ECU snag?
What ECU are you running Eric?
 

Eric B

Eric
I run the 8 stack/Borla "Weber" set up and have done for 10yrs. I don't have any issues with it at all. Infinitely superior to actual Webers for driveability IMHO. What makes you think it is not an ECU snag?
What ECU are you running Eric?
I "was" running the Fast XFI 2.0 at the time. Dynatech (who manufactured the system at the time) had me take the car up to Philadelphia for their "expert" tuner to tune the car when the drivability issues could not be solved by me. The shop in Horsham, PA told me that the car would be ready in 7 weeks. 7 months later (new throttle bodies, new intake, and two sets of injectors) I went up and recovered my car and trailer. The car ran worse, and I left $4,500 poorer.

On a rather dramatic drive home (long story), my wife told me to put a carburetor on it. I did.

It could be the cam. On paper it looks okay, but it may have too much overlap.

I have owned Webers, and yes the 8-stack system started better, was consistent on idle, and no barometric issues.

I just had a problem on the map that I could move, but not rid.

E
 

Larry L.

Lifetime Supporter
I "was" running the Fast XFI 2.0 at the time. Dynatech (who manufactured the system at the time) had me take the car up to Philadelphia for their "expert" tuner to tune the car when the drivability issues could not be solved by me. The shop in Horsham, PA told me that the car would be ready in 7 weeks. 7 months later (new throttle bodies, new intake, and two sets of injectors) I went up and recovered my car and trailer. The car ran worse, and I left $4,500 poorer.

On a rather dramatic drive home (long story), my wife told me to put a carburetor on it. I did.

It could be the cam. On paper it looks okay, but it may have too much overlap.

I have owned Webers, and yes the 8-stack system started better, was consistent on idle, and no barometric issues.

I just had a problem on the map that I could move, but not rid.

E
No one I know who's installed an 8 stack or Weber look-alike system (regardless of manufacturer) ever got it to work right...even after HOURS of 'over-the-phone' tuning with 'the factory'.
Like you, they removed the injection and went to either a duel or single 4 barrel carb intake. 'No problems/no issues since.
 

Eric B

Eric
No one I know who's installed an 8 stack or Weber look-alike system (regardless of manufacturer) ever got it to work right...even after HOURS of 'over-the-phone' tuning with 'the factory'.
Like you, they removed the injection and went to either a duel or single 4 barrel carb intake. 'No problems/no issues since.
Larry, you are referring to the Weber throttle bodied 8-stack or similar design. Yeah, except for show cars and racing applications I have not spoken to anyone that got it to run correctly. For racing, I do not think it would be an issue. Several folks have asked to buy my 8-stack, but I ask if they are going to drive it on the street, and if they are I politely tell them I will not sell them the system. I couldn't put the strains I had onto someone else. Makes a good talking piece though.....

I have spoken to (before my current build) 8-10 people that have the Borla (TWM) system and have had good results. Now everyone tells me the ECU is self learning, but I wonder about that. None the less I could not bring myself to build a GT40 without a system that had the appearance of Webers. If it had to be a carburetor I don't think I would have done the build. The injectors over the throttle plates as used in the 8-stack system just seemed to be a problem IMO. I guess I will be able to report on this system soon enough, the car is finished, now need to get it titled.

E
 

Larry L.

Lifetime Supporter
Larry, you are referring to the Weber throttle bodied 8-stack or similar design. Yeah, except for show cars and racing applications I have not spoken to anyone that got it to run correctly.
...and that's ridiculous when you think about it.

Injection is injection. Electronic injection has been around since the Earth cooled. ALL new cars have it (be they N/A., T.T. or blower equipped). So why is it that the aftermarket just cannot seem to figure out how to make 'em operate properly???

Makes no sense to me...
 

Eric B

Eric
...and that's ridiculous when you think about it.

Injection is injection. Electronic injection has been around since the Earth cooled. ALL new cars have it (be they N/A., T.T. or blower equipped). So why is it that the aftermarket just cannot seem to figure out how to make 'em operate properly???

Makes no sense to me...
Personally, without mass air flow sensing, it is guess work. But the injectors on top of the throttle plates would dump fuel at snap throttle and it just sits there until you open of the throttle and then the ECU gets mixed signals because the O2 sensor sees the extra fuel coming out. I worked on it a long time, and I decided it is either the cam has too much overlap (several people told me it does not, but...), or it is the affect of the fuel puddling.

Now would I ever put it back on?, I don't know. Someone that would guarantee results would have to happen along. The cam with the carb now just is nasty. It really cracks off, however crusing under 1800 rpm is not possible without a load. This winter I may change the cam while addressing a perpetual rear seal that leaks.

E
 

Dave Hood

Lifetime Supporter
Eric, B. When I bought my car in 2012 the engine at the time was fitted with Dynatek's prototype Eight Stack system. The concept behind their design was excellent but the tolerance on my throttle bodies was off and the engine never ran right as a result. So the unit you purchased 10 years ago may have suffered from that production issue as well. In 2014 I had my throttle bodies rebuilt and things have been fine since then. They have since sold their company to Borla.
 
I've run the newer version TWM/Borla Stack Injection system since day one. Although it ran pretty good with the included self-learning "EZ-EFI" after a few hundred miles of 'learning', that system is only designed to control fuel. I also had a separate computer programmable ignition box, but I wanted the ECU to do it all, have more scalability, data logging, and so on, so I traded in the EZ-EFI v1.0 for their FAST XFI Sportsman, which accomplished everything I was looking for. The XFI 2.0 is fine, but is overkill for a vintage-looking GT-40, unless you plan to go with a modern fully sequential with coil-over-plug setup, and have full fuel and spark timing capability from cyl to cyl, i.e. 8-1 cyl engines.

There are a few hidden pluses to the Borla system, which I like. The hidden under the manifold vacuum chamber, the under the throttle plate injectors, center mounted fuel rails that properly angle and feed the injectors under the throttle plate, and probably the least noticed but important design is the flex couplings that are unique to the Borla. As these manifolds get hot and you have dissimilar metals expanding at different rates, these couplings flex axially, which help to minimize the interaction between the throttle bodies and butterflies, so they are binding against each other. That can cause rapid throttle bore wear, which eventually results in air leaks when the throttle plates are closed (idle) and all kinds of syncing issues since you have some cyls getting more air than others even when the throttle plates are closed. Getting each throttle body flowing the same amount of air next to each other and bank to bank are one of those key elements to getting these systems to run well. The throttle response is incredible. Not sure what the cfm rating is on the 50mm throttle bodies, but it has to be in the 1000s!

That all said, no one's mentioned the exhaust system and how well it's sealed in and around the O2 sensor(s). This is critical feedback for the ECU, so if it picks up air from an exhaust leak, you are throwing your money away and end up with a $hitty running system. So not only figure out your budget for the stack setup, also add in an EFI purposely-designed for EFI bundle of snakes. People like to blame the EFI for a poor running system, but there's a good chance little or no attention was paid to the exhaust system. Tip: Look for double-slip joints at the header-collector union, V-band clamps at the collector-muffler union, and nice thick header mounting flanges.

I have over 8000 miles on my setup now. Starts cold (tested to 20s F) and I have tested it in stop and go traffic at over 8000 feet, high water (230) and (240) oil temps, 190+ deg intake air temps, too. I've purposely stressed tested it so I could work out any bugs, and in hope that the car wouldn't let me down on a drive. Last thing, if you happen to live in or near the mountains like I do and see anywhere from 5k-11k feet of elevation (810mb ~ 670mb) change during a drive, you can wire in a second MAP sensor so the ECU sees the pressure changes and adjusts the parameters as you drive....nice to have.

In a nutshell, it runs pretty damn good and looks the part to the untrained eye!

56425623_10218493298347385_1928653526670508032_o.jpg
 
Hi all,

the Hilborn 2 7/16 EFI IR system on the 440 SBC in my McLaren M1 replica is very docile and well behaved at idle, off idle and cruise. Wide open it is awesome with monster mid range punch. At it's core this is a Shafiroff ultra-street crate engine with around 250 duration and 109 LSA so not a small cam either. I tuned it myself and it is a speed density system controlled by a Link ECU.

Bottom line is that if you have a decent linkage that maintains sync, good stable vacuum signal and fuel system, decent sensors and ECU, and you know what you are doing, I think most systems can be made to work very well. FWIW, I also talked to Kaspa in November last year about the super-cheap Speedmaster system that was on run-out sale for LS engines. He is an experienced guy and said exactly the same thing about his experience with that on his engine. So there is no need to drop big coin on these things.

Cheers, Andrew
 

Glenn M

Supporter
No one I know who's installed an 8 stack or Weber look-alike system (regardless of manufacturer) ever got it to work right...even after HOURS of 'over-the-phone' tuning with 'the factory'.
Like you, they removed the injection and went to either a duel or single 4 barrel carb intake. 'No problems/no issues since.
As you don't know me Larry I'll let you off with that statement.
Mine however runs brilliantly. I ran Webers before and I have never looked back since changing. Starting, tickover, light and hard running are all improved and gobs more power! I am using the Accel ECU and right from the first start it has been wonderful. The tuner I used had nothing good to say about self learning ECU's so that's where I would point the finger. You get what you pay for. You need a proper ECU that you can programme all the different facets to suit your car and engine and someone who knows what they are doing setting it up.
I use my car on track and road and I would have no hesitation in wholeheartedly recommending it to anyone.
I notice that you don't mention what ECU "all the people you know" were using, you just blanket blame it on the hardware. That seems a little unfair to me, just half the story.
 
Last edited:
...and that's ridiculous when you think about it.

Injection is injection. Electronic injection has been around since the Earth cooled. ALL new cars have it (be they N/A., T.T. or blower equipped). So why is it that the aftermarket just cannot seem to figure out how to make 'em operate properly???

Makes no sense to me...
The only way I have managed to make the 8 stack system work was to persevere.
1. You will need to delete all the supplied linkages if they are not already rose jointed as well as adjustable balance links left & right sides this is critical otherwise you will never get good TB balance.
2. I moved the fuel rails to the centre (no machining) simple swap around also need to change the handing of the centre cable linkage (new spring is all that's needed) This moved the injectors spray direction straight into the intake runners.
3. Slight modification to the fuel rails is required to keep the original distributor look ( shortened them and welded new bosses on top of the ends & locked on to the mounts with grub screws) I wanted the Turkey pan to keep the original look.
4. Change the distributor to a dual hall sensor type if you intend keeping the distributor. (no crank sensor needed)
( I don't run vacuum my Cam is to aggressive all I use is the TPS, Map sensor to atmosphere & engine Temp sensor and full lambda on a single collector with the crossover I'm getting readings from both banks of cylinders).
5. I run a single high energy Bosch coil ignition system (simple but effective.)
6. I used Motec ECU full sequential.
7. DONT USE THE MECHANICAL TPS THE TUNE WILL ONLY LAST FOR 750 to 2000 Klm as the Mechanical TPS will wear with the vibration and you never be able to maintain any tune. You must use a Magnetic contactless TPS its been faultless since I've changed it.
7. Biggest issue i had to overcome was the lack of knowledge of so called experts when it came to the tuning. Timing map was never properly looked at once i got that correct it ran perfectly.
 
7. DONT USE THE MECHANICAL TPS...
Agree, I went straight to the contactless (Hall-Effect), Throttle Position Sensor knowing that this is one of the most important sensors in the system. The Penny+Giles (TPS280DP) is the upgrade option that was/is offered with the Borla Stack System. Sealed to prevent water intrusion, and life tested to over 30-million cycles...

tps280.jpg
 
Top