Has anyone tried NOS Topshot?

[JoePapa]

This is the link:

http://www.holley.com/HiOctn/ProdLine/Products/NOS/NOSNS/TopShot.html

Has anyone here tried this and if so what's your feed back on it? I'd like to know how well it performs.

Thanks!!

[JoePapa]

This is the link:

http://www.holley.com/HiOctn/ProdLine/Products/NOS/NOSNS/TopShot.html

Has anyone here tried this and if so what's your feed back on it? I'd like to know how well it performs.

Thanks!!

[Sporter]

I'd also like to know, specifically how it works with a Qjet.

[JoePapa]

Here's the install doc - that may help with the Q-jet question.

http://www.holley.com/TechDocs/Instructions/NOS/Sheets/A5062-SNOS.pdf

My understanding is it sits in the air cleaner so it's great for our minimal hood clearance since it's not under the carb.

What I don't know is the quality of boost compared to a plate system. Is it good performance and not a concern or does it suck wind and we'd be better off getting port injection? (Assuming no hood clearance for plate injection.)

Joe

[LiL Jack]

I know that you can't put alot of spray through it.

[Tom Vaught]

I agree that the average muscle car will not see much benefit but I will tell you personally that one of those systems on a GM rental car with a couple of mini bottles can be a bundle of laughs!! http://forums.performanceyears.com/groupee_common/emoticons/icon_biggrin.gif

Tom V.

[Big Injun]

We have been running a Top Shot unit on Jim Wangers' Ponte Carlo for years. We can run upto 220 hp on the unit. The car runs deep in the 9s on just this unit. A great benefit of the Top Shot is it cools the intake charge while improving the signal to the carb.

According to the "old" NOS guys, Waddy and Thermos (the guys that made NOS the leader it was until Holley bought them) the Top Shot is the most efficient system they ever developed.

The system really works best with a square bore carb...not a Q-Jet.

[JoePapa]

Tom -
What do you mean but not much benifits for avg. muscle car - do you mean the 150hp advertised rating? (Nice rental car trick!)


Big Injun -
WOW! The system is rated from 75-150 hp range. Did you just change out the jets to hit the 220hp level or did you do some other modifications? I have a square bore 825cfm mighty demon carb this will be going on.

It's interesting that you say it's the most efficient - I would have thought it to be less efficient since it's on the top side of the carb... go figure! That was my whole concern but doesn't sound like I should be worried about that! http://forums.performanceyears.com/groupee_common/emoticons/icon_smile.gif

Thanks guys!

Joe


PS - I'm okay with 150hp shot but would rather it offer up to 200. I don't currently plan to go over a 200hp shot.

[Ron]

When you install the Top Shot it shoots right down in to the venturies of the carb. It works great with a Q-jet but is simply outstanding with a Holley. The Top Shot mounts on the air cleaner stud.

Like Dave said, one of the founders of NOS, Mike Thermos, said it was the most efficient system they have.

[PONTIAC DUDE]

Before the Ponti Carlo it was on the Red T/A that 'Dirty Ed' drove for Jim.

Dirty Ed swore by it. http://forums.performanceyears.com/groupee_common/emoticons/icon_wink.gif
Flip flops and all. LOL.

[Ryche400]

My buddy ran that system years ago in his Chevy pick-up. It ran very respectable for its time.

[JoePapa]

Thanks for the replies folks. Looks like it's cheaper, easier to install, and efficient... great combos!

[Tom Vaught]

The amount of power you make is based on the amount of oxygen and fuel you
put into the hole. (We all know that).

My comment was based on if Thermos said it was a 150 shot it will be a 150 shot
(in engine hp)in most cases. You will not get a lot more hp out of the "as bought"
system.

In Wanger's case naturally they had tweeked the system to get the 220 hp they
posted they got. I agree also with the cooling of the charge and the slightly
higher booster signal deal too.

When carbs are flowed dry they flow more than when they have fuel running throught them. You blow NOS through the carb it takes up space too but the
Nitrous gives you more benefit for the little reduction in air flow throught
the carb. Same for the fuel being sprayed into the venturis. It takes up space
but the fuel is atomized better when it hits the carb so the overall effect is
better.

The reduction in the charge temp is a big deal though.

Sorry for the confusion.

I would like to know how they measured "Efficiency" though.

Tom V.

[evilpeanut]

According to the instructions:

"CAUTION! The Top Shot Module is intended only for use with carburetors that feature mechanical secondaries. This
unit should not be installed on carburetors with vacuum secondaries, such as Rochester Quadrajet.
Attempting to do so could result in an engine fire."

Is there a way to use this with a QJet or is that asking for trouble?

[PONTIAC DUDE]

Asking for trouble. http://pysales.com/images/sweat.gif

However, Underneath with a vac. carb not an issue as the port/valve is directly open to the plate all the time.

[SupergasDil]

I had actually purchased a Topshot system from Ed when he was working with Jim Wangers. Ed was very helpful and knowledgable about the Topshot. I used mine with the 150 jets through a Demon 850 with a hand held switch. Hitting the button after I was sure the rear tires had stopped spinning in second gear I gained a solid 4 tenths and 8 mph. And that was through an RPM intake. I had more fun with that setup than I do with the blower. http://forums.performanceyears.com/groupee_common/emoticons/icon_wink.gif

[1968_Injunhed]

For the Q-jet, I bet you could rig a micro switch to respond to the air door opening, if it wouldn't make it not move properly. Cliff?

[Ron Landis]

As Warren Johnson once stated to NHRA officials;"You can introduce nitrous from the tip of the air scoop to the back of the intake valve with similar results." But what does he know? This was during the "Dodge Boys" fiasco, his point being that it may not always be obvious. Stealth is the major advantage of the "Top Shot" design.

[David Holmberg]

The LS1 dry shot is inserted in front of the radiator. On my Stock Convertible a 90 shot picked the car up from a 13.4 @ 104 to a 12.6 @ 116. This was waiting to hit it until after the shift to 2nd due to street tires.

So yes, you can add nitrous just about anywhere in the air system with good results.

[PONTIAC DUDE]

So a shot in the carb hat with a fogger nozzle and an ATI Supercharger would be ...............

http://forums.performanceyears.com/groupee_common/emoticons/icon_eek.gif http://forums.performanceyears.com/groupee_common/emoticons/icon_biggrin.gif http://forums.performanceyears.com/groupee_common/emoticons/icon_biggrin.gif

[1968_Injunhed]

Could you turn it around and set it up backwards where it would spray in the primaries for Q-jet use?

Just thinking out loud...thats what you smell burning http://forums.performanceyears.com/groupee_common/emoticons/icon_biggrin.gif

[JoePapa]

Ok - one last question on this thread. The Top Shot retails for about $489. The sportsman fogger retails for $649 and has a wider HP range. 150HP is a good shot and I don't know if I could afford to refill bottles by spraying more then that. However, would there be enough benefit from direct port injection or is the incremental gain not worth the effort for recreational racing. I just wanted to ask this last question before ordering the Top Shot since the incremental cost is only about 150 bucks.

Thanks in advance.

Joe

[JoePapa]

Well I got to thinking on this and decided to call Holley NOS tech support. The guy there said that the fogger nozzles are really more efficient but really gain the advantage at the higher HP levels. The 150-200hp range is negligible. He also mentioned that I can hit 175HP with simple jet swap. I think the TopShot will be my next purchase for 1/4 mile gains http://forums.performanceyears.com/groupee_common/emoticons/icon_smile.gif

[tininjun67]

I'd go with a ported system. the consistency in fuel/nitrous distribution would be worth the extra cost