Here's a link to Holley's tech support (sniper product) site: https://www.holley.com/support/

They also have a phone number for talking to a tech support person: 1-866-464-6553. I realize you are in Australia, so you may need to add the USA country code in front of that number. If you go to the link above, you can email a tech and explain or provide your question(s) which would be cheaper than the phone call perhaps.

Would like to see a pic of a RHD 69 Camaro conv! Was this sent out from the factory this way?

 

I assume you are using the Holley Sniper EFI. I would give Holley a call. Their tech support is good and they should be able to guide you on a better tune for your engine.

 

Are the stats you posted programmed target settings or readings with engine running data log?

My guess is possibly bad O2 sensor.

You can run the set up wizard to reset

 

The Holley support forums are helpful and Danny is always there to help you solve your problems.

 

Hi Guys, and thanks for your quick replies,

the RHD conversion is a cut and flip job, so a mirror image of the LHD

The O2 sensor is correct as it matched the dyno reading...

The settings and reading on the hand controller as very close...

I guess its tech support time

wish me luck

thanks

G.

 

Good luck! Let us know the out come.

 

Self tuning algorithms generally don’t work well with big cams. If it’s running rich but giving good AFR readings check for exhaust leaks before the O2 sensor.

Don

 

Hello i am new to forum. I actually only register to reply to this post. I have sniper efi as well on my 437 started as a 427 but ate some vitamins and grew big and strong. You never mention trans or convertor. I never dynoed the motor but when I put it on a chassis dyno i too was disappointed. I only made 350hp 380tq to tire. For street caprice this is great but i was hoping for more. I have you tube channel my name is cfmechanic. Been driving over a year. To see someone else making similar numbers was shocking to say the least. I am in ventura california have th350 trans shift kit 3000rpm stall convertor and 3.42 rear gears car does 0-60 in 4 sec and weighs over 4000lbs. It could be faster but im satisfied. You making 550 580 at crank ans 350 to tire i feel much better. Old school automatics really seem to eat hp and not programming torque convertor also will cause low readings. I have since swapped intakes from dual plane to single and can feel the difference. Been tuning it with my laptop over a year now. Still learning everyday.

 

More info i have a cam that is 240/244@50 .608/.614 lift 112 lsa run 160 thermostat Afr 195 race port heads dss gsx pistons flat tops 10.5:1 compression motown single plane intake 1inch spacer. With my cam i have to manually tune. If i transfer the learning to base i have to hook up laptop to lower the idle area back. When learning is added and smoothed idle gets too rich so i have to manually take fuel away at idle circuit. My map idle is anywhere from 70-50kpa i am at sea level. Cruise is 30-40 and wot is 80 and up. My afr targets are 14.1ish for idle 14.8 is for cruise and 12.8 for wot. I also have videos of car on dyno no smoke until you lift then I get some blow by. My machinist blames my 4inch stroke causing turbulence. I attribute it to wide ring gaps for nitrous. I plan on adding some power adder someday. I figure if your making 550 at crank I must be as well at first i was using the 15% rule and couldnt figure out where the horses went

 

Holley Tech Support should be able to help you. I've had to call them and they help me out and got my Vette running good.

 

350 rwhp does not translate anything close to 550-580 at the crank. Drive train loss, even with a TH350 is not almost 40%. Ballpark loss is 18% - 20% with the old school autos.

Have these engines been run on engine dynos to determine actual power #s?

 

Hi Guys,

I am relatively new here...

Car is a Camaro 1969 conv. Auto RHD (I am in Australia).

With the original 350 SBC (300hp) it was smooth but slow

The new SBC Dart SHP 427/AFR 210 heads/ CompCams XR294HR/ Sniper EFI, and all the rest of the good stuff.
On the Dyno it was great around 550Hp and 580lb all under 5700rpm, perfect for the street. Between the engine
Dyno and completing the installations, my engine builder and I had a "disagreement" about the responsibility of leaks...

Anyway, to my problem...

After a few hundred miles I decided to put it on the chassis Dyno, well that went bad besides only hitting around 350rwhp,
with only I pull I smoked out the whole workshop...

My tune is no good...

Here are my stats:

AFR
Idle 14.7
Cruise 14.7
WOT 12.8

Ignition
Idle 25
Cruise 36
WOT 36

IDLE jumps between 800-950, set to 900rpm

Is there a way to rest the the Sniper so it re-starts learning from scratch?

and are my starting points (AFR and Ing) ok?

thanks

Greg

350 rwhp does not translate anything close to 550-580 at the crank. Drive train loss, even with a TH350 is not almost 40%. Ballpark loss is 18% - 20% with the old school autos.

Have these engines been run on engine dynos to determine actual power #s?

Lost in the middle of the OP are his engine dyno numbers. I'm no guru on this stuff but 40% does seem outrageous.

Jeff

 

A properly tuned engine making 500 RWHP is probably making low 400's HP (415-435) at the crank on an engine stand dyno. My only personal experience is with a Dyno-Jet chassis dyno, from what I've heard... Mustang Dynos will show slightly less HP on the same car.

 

You have it backward. Crank HP is always more than RWHP.

 

Many factors contribute to chassis dyno #s. Tire size and rear end gears to name a couple. Therefore 2 engines with same crank HP and Torque will yield different #s on the same dyno if they have different gearing for example. You often see faster cars will lower #s than others.

Dynos are a tuning tool. Great for establishing a benchmark and comparing after mods and tuning to measure increases and sometime decreases.

 

What chassis dyno did you run it on? Mustang’s read lower than Dynojet’s. Years ago I ran my car on both, it made 347 on the Mustang and 382 on the Dynojet. It still ran low 11’s regardless of the number, and this was a little 355 with less torque than your 427.

 

I am a Holley EFI supporter, I recommend them over anything else in EFI.

Of late, I am hearing a LOT of ignition complaints regarding the Sniper system. This system uses either a direct locked out timing phasing input from a magnetic sensor, or, analog weights and springs, vacuum advance ignition system. Almost every issue stems from the analog ignition operation with the EFI, as in the curves are not well liked, and don't work well.

The Sniper does not use an EFI HEI module, the electronic timing computation and operating module are inside the EFI computer, and that is the reason it does not need a module, only the locked out electronic timing input signal, with correctly "aimed" rotor to cap phasing.

I'd rather see a Terminator or other Holley system that uses a dedicated GM EFI=HEI module used, the Sniper has issues on a couple of areas not resolved easily.

 

The Holley Terminator is definitely worth the extra $$ ...

 

Why Holley didn't make it workable for a good, easily workable ignition system on the Sniper, is a mystery to a lot of us.

 

I have installed 4 Snipers with MSD Dizzys without issues both SBC and BBC. On 3 of the 4 we chose not to control timing. The systems have performed well without any problems.

We changed one to the Holley Dual Sync for timing control.

That said I agree there are some challenges when trying to get timing control with the magnetic pick up MSD module. Did not use ignition boxes on any of the installs.

 

Yup, since Holley bought MSD, and MSD had then owned Mallory for two years, it has been spend more, spend, more and...spend more to do what a simple stock GM EFI HEI distributor should have been able to do in the first place on a Sniper EFI system, without a bunch of hooey and problems, by simply dropping it in, plugging it in, and going.

 

I had that exact issue while helping a buddy install a Terminator system. Holley sold him a fancy whiz bang distributor that gave us nothing by trouble. He finally yanked it out and put in a simple GM small cap computer controlled distributor... fired right up and ran fine. (25% of the price) Less is more sometimes...

 

A LOT of people just don't realize that that particular small diameter, locked out, 8 pin EFI-HEI distributor works EXCELLENT with the Holley systems that have "inside the box" ignition curve control systems that are designed to work with them. They are simple, plentiful, and don't cost an arm and leg. Now, a "dual synch" setup works well when the EFI computer is set up to use it for a sequential system, or a system that uses one, but, the dual synch just ain't needed for a Terminator.

So, Holley made it a nearly required item for the Sniper, that is what happens when a company buys another, to get exclusive parts for their systems, instead of keeping it K.I.S....S.