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Have any of you converted your TBI to a Holly self-tuning Sniper EFI system?? I am thinking about taking this route with my ‘91 and haven’t been able to find any information on the net for what I would be getting into.
I reached out to Holley’s customer service department for some general direction and they ghosted me…. Just thought I would check here for some preliminary information from you guys! Cheers!
Have any of you converted your TBI to a Holly self-tuning Sniper EFI system?? I am thinking about taking this route with my ‘91 and haven’t been able to find any information on the net for what I would be getting into.
I reached out to Holley’s customer service department for some general direction and they ghosted me…. Just thought I would check here for some preliminary information from you guys! Cheers!
I'm in the process of putting my car back together with a Holley terminator stealth, car was originally TBI. It appears to be a relatively simple install. Biggest challenge is figuring out what to do with all of your existing engine wiring.
Here is the pdf for my system, I don't think the sniper would be much different.
I'm in the process of putting my car back together with a Holley terminator stealth, car was originally TBI. It appears to be a relatively simple install. Biggest challenge is figuring out what to do with all of your existing engine wiring.
Here is the pdf for my system, I don't think the sniper would be much different.
The existing wiring is one of the things I was worried about. What exactly did you do? Just tuck it out of the way or did you remove it entirely? Also, from what I’ve read, an existing FI car won’t need any mod to the gas lines as we already have 2- was that your experience?
How many hours would you say you had into the swap? I will need to pay to have it installed so trying to get an idea there as well. Thanks so much for the info!
The existing wiring is one of the things I was worried about. What exactly did you do? Just tuck it out of the way or did you remove it entirely? Also, from what I’ve read, an existing FI car won’t need any mod to the gas lines as we already have 2- was that your experience?
How many hours would you say you had into the swap? I will need to pay to have it installed so trying to get an idea there as well. Thanks so much for the info!
I removed the engine harness. Stock fuel lines should work, I'm replacing mine with a new set as mine were rusty.
My car is in pieces and I am putting in a new engine so I have no idea how many billable hours it would take to do a straight install, sorry. You will need a new fuel pump since the TBI pump doesn't make enough pressure for the holley system to work so factor that in if you want to go this route.
I removed the engine harness. Stock fuel lines should work, I'm replacing mine with a new set as mine were rusty.
My car is in pieces and I am putting in a new engine so I have no idea how many billable hours it would take to do a straight install, sorry. You will need a new fuel pump since the TBI pump doesn't make enough pressure for the holley system to work so factor that in if you want to go this route.
This is all great information!! My original stock fuel pump is dead so I already planned on replacing. So, that won’t be an issue at all. I looked at the model you got and it doesn’t appear to be “self-tuning”. That is one of the main reasons I want to go with the Sniper. I have a heads & cam 305 and was never able to get the tuning right (Dynamic EFI Flash EBL).
I’m hoping if I go with the Sniper it’ll be able to dime things in better than I have them now (which probably isn’t hard to accomplish lol). Thanks for the feedback!!!
This is all great information!! My original stock fuel pump is dead so I already planned on replacing. So, that won’t be an issue at all. I looked at the model you got and it doesn’t appear to be “self-tuning”. That is one of the main reasons I want to go with the Sniper. I have a heads & cam 305 and was never able to get the tuning right (Dynamic EFI Flash EBL).
I’m hoping if I go with the Sniper it’ll be able to dime things in better than I have them now (which probably isn’t hard to accomplish lol). Thanks for the feedback!!!
It is self learning.
"The Terminator X Stealth 4150 EFI system from Holley features 4, 100LB/HR Fuel Injectors capable of supporting up to 650 HP naturally aspirated or 600 HP on forced induction applications. The Terminator X ECU is capable of fuel map self-learning and ignition timing control, improving idle stability, drivability, and wide-open throttle horsepower! Did we mention that the Stealth 4150 also includes transmission kick down provisions for GM TH350/400, 200R4/700R4 and Ford C4/C6 applications? Terminator X Max Stealth 4150 kits provide transmission control for Pre-2009 GM 4L60E/4L80E Transmissions (Part numbers 550-1011, 550-1012, 550-1013)"
I chose the terminator over the sniper due to the fact the terminator has a divorced ECU whereas the sniper has the ECU inside of the throttle body. I just didn't feel good about having my ECU sitting on top of the intake getting hot and being exposed to dust, water and fuel.
I totally missed that it was self-learning! I was wondering about the durability of the ECU on the Snipers as well. Totally don’t blame you for going with the one you did for the design. Hope to see some posts of how you like it once you get it all back together!
QUOTE=WildCard600;6526662]It is self learning.
"The Terminator X Stealth 4150 EFI system from Holley features 4, 100LB/HR Fuel Injectors capable of supporting up to 650 HP naturally aspirated or 600 HP on forced induction applications. The Terminator X ECU is capable of fuel map self-learning and ignition timing control, improving idle stability, drivability, and wide-open throttle horsepower! Did we mention that the Stealth 4150 also includes transmission kick down provisions for GM TH350/400, 200R4/700R4 and Ford C4/C6 applications? Terminator X Max Stealth 4150 kits provide transmission control for Pre-2009 GM 4L60E/4L80E Transmissions (Part numbers 550-1011, 550-1012, 550-1013)"
I chose the terminator over the sniper due to the fact the terminator has a divorced ECU whereas the sniper has the ECU inside of the throttle body. I just didn't feel good about having my ECU sitting on top of the intake getting hot and being exposed to dust, water and fuel. [/QUOTE]
I'm hoping the latest version has the ability to do this, but I have not had time to look into it.
I was thinking about this a little tonight and I wonder if you couldn't use one of the extra output wires on the terminator system like I have and use it for a relay on an electric converter control module. There is one unused output the system can control though I can't power up my system to see what parameters are definable. There is also the a/c shutdown feature that is already in the system that I wonder might be utilized if you could again, properly define the needed parameters.
The higher end units should be able to do it for sure, but at almost half again higher price point.
The aftermarket EFI companies are absolutely non-responsive to issues.
I put a Proflow 4 system I bought for $1200 new in the box on an 87 G20 with a L31 based 350 in it. Runs decent, but that system has a terrible manifold for low-speed torque out of the box and no ac compensation. Doing it over again, I would just buy a L31 marine MPFI manifold, a BP Engineering Gen3 LS DBC harness and use L31 electronics with a 24x reluctor and 0411 or P59 upgrading to the LS coil near plug at the same time. As for the engine bay wiring, deleting the TBI wiring was easy with the correct GM wiring diagram from the C100 connector in the engine bay. I retained the wiring for the fuel pump, oil pressure sending unit, coolant temp sender and TH400 kickdown relay that I added a mechanical detent switch to the gas pedal to control it in place of the TBI ECM by grounding the kickdown relay at WOT. The Edelbrock EFI system requires battery power (which I fused near the battery because Edelbrock did not), ground and 12v switched power (used the pink OE TBI ignition coil wire) and the OE TBI fuel pump relay is controlled off the Proflow 4 ECMs fuel pump output which I also kept the oil pressure switch in-line with.
I swapped from the single plane proflow manifold to a mercruiser dual plane MPFI manifold, big gain in torque.
If you are going through the hassle of a EFI swap, might as well go with full sequential port injection.
Thank you for all the information! I’m very much in the planning stages so will definitely dig into everything you have suggested. Also, a very good point about sequential injection and one I have considered.
Thank you for all the information! I’m very much in the planning stages so will definitely dig into everything you have suggested. Also, a very good point about sequential injection and one I have considered.
Also something to consider, Holley charges a lot of money for the Hyperspark add on. Edelbrock provided a dual sync distributor and timing control out of the box. Edelbrock does not supply the fuel pressure regulator or ignition coil though. Just throwing that information out for anyone interested in either system.
So far I have really liked my sniper EFI. Installing the hyperspark kit cant wait to try it in the spring
Nice to find someone on here running one!
What are your impressions with the self-tuning? What intake/ fuel pump did you use with yours? I’ve read great things about the hyperspark— what ignition set up are you running right now on it? I was actually unsure if these kits would work with the factory style distributors which is what I currently have…
Also something to consider, Holley charges a lot of money for the Hyperspark add on. Edelbrock provided a dual sync distributor and timing control out of the box. Edelbrock does not supply the fuel pressure regulator or ignition coil though. Just throwing that information out for anyone interested in either system.
My holley can control timing with the stock GM HEI distributor.
So far I have really liked my sniper EFI. Installing the hyperspark kit cant wait to try it in the spring
That's a nice addition to the system (and at $550 it should be), but is aimed at electronically controlled transmissions (like a 4L60E), not a 700R4. I'm not sure if it could be used for TCC only or not. Their write up doesn't seem to indicate that it can.
What are your impressions with the self-tuning? What intake/ fuel pump did you use with yours? I’ve read great things about the hyperspark— what ignition set up are you running right now on it? I was actually unsure if these kits would work with the factory style distributors which is what I currently have…
Edelbrock air gap also ran a RPM performer for a while. For about 3 years I ran a MSD 8360 with SS coil. I am in the process of changing it to their hyperspark now no idea about a factory distributor. I am running a modified factory pickup and walboro 255
Self tuning works great and learns relatively quickly. The system only tunes when it reaches temp so you may need to adjust values for cold operation but they are just offsets from the base self tune so they are usually close I adjusted my idle a little and added fuel for cold starts <50F.
Edelbrock air gap also ran a RPM performer for a while. For about 3 years I ran a MSD 8360 with SS coil. I am in the process of changing it to their hyperspark now no idea about a factory distributor. I am running a modified factory pickup and walboro 255
Self tuning works great and learns relatively quickly. The system only tunes when it reaches temp so you may need to adjust values for cold operation but they are just offsets from the base self tune so they are usually close I adjusted my idle a little and added fuel for cold starts <50F.
I have a Delphi made EP381 stock replacement Vortec pump in mine on a Spectre TBI sending unit in a Dorman tank that has a massive fuel sump in it. I have run those pumps on a 500 hp engine using 43.5 psi. They flow ~190 lph @ 58 psi and flow increases at 43.5 psi. Pump is extremely quiet and does not draw a ton of amps. GM Performance included the same pump with the 502 hp Ramjet 502s.
I was talked pit of the Sniper by almost every shop I talked to. Most of their reasoning was that the ECU is very susceptible to outside RF interference. I also learned that Holley has a massive return rate on the Sniper. The Terminator is a much better designed unit.
I was talked pit of the Sniper by almost every shop I talked to. Most of their reasoning was that the ECU is very susceptible to outside RF interference. I also learned that Holley has a massive return rate on the Sniper. The Terminator is a much better designed unit.
1st time hearing this, but GOOD to know!!! Thank you all for the information guys!!! It is so nice to finally get the answers I’ve been looking for!
Holly just redesigned the entire system to deal with a lot of complaints from the old ones although I've never had an issue I thought I had an RFI problem turned out to be a loose fuse.
03-07-2024, 05:58 PM
