LACK OF PERFORMANCE - 1970 440 WITH HOLLEY SNIPER 1

[1970CUDAAAR]

I recently purchassed a 1970 CUDA 440 with a Holley Sniper 1. The motor has been redone with many new stock parts (no upgrade to the cam or other performance items). It should develop around 375 to 390 HP. It does not seem to develop as indicated (375 to 390 HP) since it does not even make the wheel spin when pushing it to max feeder at take off. In my opinion it should do this. I have a small gear 3.23. I think that the Sniper is out of adjustment and does not perform as it should be. I had an occasion where the car whent to 220 degree and I stopped it and had a hard time starting it again. Any help on how to correct this situation will be much appreciated. I'm not looking for a boom performance car - just what it is suppose to do. I'm worried that theire are some issues with the engine - I dont understand since the engine runs good.

Another issue I have is that on the first start I starts very quickly and runs good - sometimes it does not start easy when I start it after being shut down for a few hours.

Thanks!

 

[Xcudame]

Assuming you have a 16psi radiator cap, 220°F is awful. System is good for 250°+F with that cap. A tight rebuild will have more friction until everything is broke in well. Definitely sounds like a fuel issue. I'm not too familiar with Holley Sniper fuel injection. I do know Holley and the folks on here will help you. Do you know the fuel line size (5/16 or 3/8) and what fuel pump (hopefully electric near the fuel tank) your car has? What's the intake manifold vacuum at idle? What's the idle timing? What is the total timing at 3000rpm. These are very helpful to diagnose the problem.

 

[Adam]

The Sniper has full adjustment on the air fuel ratio. You need to adjust the afr to the optimum for the rpm/load. Go to the initial set up menu and make sure the engine parameters are properly set up 8 cyl, 440 ci, mild cam, etc. This should be good enough to start, but it will probably be rich. The system should be wired to a temp sensor so it can adjust when cold/hot. You can also adjust the accelerator pump function. Bottom line, find the tuning directions and start at the beginning. Also there is undoubtedly a Sniper forum where you will find recommendations for your afr at idle, cruise, wot, etc.

Oh, and make sure it is wired directly to the battery or it will lose all the programming when shut off and run like dog crap when you restart it.

Lastly, like Xcudame said, dial in your total timing to 34 degrees with the vacuum advance disconnected.

 

[pschlosser]

Adding my two cents worth:

The Holley Sniper carburetor can be dialed in precisely making the engine sing and run better than a factory carburetor. You can take it to a shop to tune it and dial it in. And if you learn to do it, yourself, then if/when the settings are reset and lost, you'll know what to do to put things right once more.

Some tuning topics to review are air/fuel mixture, accelerator pump timing, and automatic choke settings.

A lean engine may run hot. An idling engine should not overheat. If yours is overheating at idle, then you may have cooling issue(s) to diagnose and resolve.

Most 440 engines, even the 2-barrel mild camshaft ones, will be able to spin the tires in a passenger car from a full stop, especially if applying a little brake beforehand. But this is vague measure of the engine's performance.

Unless you have the 1969-1971 high performance 440 engine, with the six pack connecting rods and special harmonic balancer, and/or if your engine is high mileage, you may only see 300 HP at the wheels. Even 300 HP is nearly double that produced by the 318 engine.

 

[1970CUDAAAR]

En ajoutant mes deux cents :

Le carburateur Holley Sniper peut être réglé avec précision pour que le moteur chante et fonctionne mieux qu'un carburateur d'usine. Vous pouvez l'apporter dans un magasin pour le régler et le composer. Et si vous apprenez à le faire vous-même, alors si/quand les paramètres sont réinitialisés et perdus, vous saurez quoi faire pour remettre les choses en ordre.

Certains sujets de réglage à examiner sont le mélange air/carburant, le calage de la pompe d'accélérateur et les réglages du starter automatique.

Un moteur pauvre peut chauffer. Un moteur au ralenti ne doit pas surchauffer. Si le vôtre surchauffe au ralenti, vous pourriez avoir des problèmes de refroidissement à diagnostiquer et à résoudre.

La plupart des moteurs 440, même ceux à arbre à cames doux à 2 barillets, seront capables de faire patiner les pneus d'une voiture de tourisme à partir d'un arrêt complet, surtout si vous freinez un peu au préalable. Mais il s’agit là d’une vague mesure des performances du moteur.

À moins que vous n'ayez le moteur 440 haute performance 1969-1971, avec les six bielles et l'équilibreur harmonique spécial, et/ou si votre moteur a un kilométrage élevé, vous ne verrez peut-être que 300 CV aux roues. Même 300 ch représentent presque le double de celui produit par le moteur 318.

H!
Can soneone gives ne the basic set up for à Sniper on a 440 Mopa Timing - AFR - IAC - ETC. Thanks!

 

[pschlosser]

This seems a Holley Sniper problem more than a Chrysler/Mopar problem. To solve, you may need to seek out a Holley Sniper forum for advice. Not many of us know Holley Snipers that well.

https://forums.holley.com/forum/holley-efi/sniper-efi

 

[Xcudame]

I'd call Holley tech services and tell them what you have and get their advice. They will help you.
1 866-464-6553

 

[sir_veza]

I recently purchassed a 1970 CUDA 440 with a Holley Sniper 1. The motor has been redone with many new stock parts (no upgrade to the cam or other performance items). It should develop around 375 to 390 HP. It does not seem to develop as indicated (375 to 390 HP) since it does not even make the wheel spin when pushing it to max feeder at take off. In my opinion it should do this. I have a small gear 3.23. I think that the Sniper is out of adjustment and does not perform as it should be. I had an occasion where the car whent to 220 degree and I stopped it and had a hard time starting it again. Any help on how to correct this situation will be much appreciated. I'm not looking for a boom performance car - just what it is suppose to do. I'm worried that theire are some issues with the engine - I dont understand since the engine runs good.

Another issue I have is that on the first start I starts very quickly and runs good - sometimes it does not start easy when I start it after being shut down for a few hours.

Thanks!

Not sure you have a motor issue from what you wrote. You may want to see if your fuel pump is compatible with an EFI system. A stock or similar pump will only push around 7 PSI which is nowhere near what EFI needs. IMO the folks at Holley can advise you better on where to start...