I just ordered my FAST 90/NW TB Combo and I just hate to use a wet kit on an intake that already has direct port bosses.

I used the Search function and even poked around the internet hoping to find a good read about different Direct Port setups, but I didn't find exactly what I was looking for (aside from some SWEET looking setups from Dave). I'm hoping you all can help!

I'm still on the stock bottom end and I'm only looking to run a single stage 200 shot for now, but adjustability for bigger shots in the future would be nice. I will be running a Racetronix pump setup, but stock fuel system aside from that. I don't need a dedicated fuel system to use a DP kit, correct?

From what I understand, direct port is the safest and most efficient means of using nitrous, correct? It would be nice to eliminate the chance of backfiring through the intake or leaning out a cylinder.

I'm also looking to stay below or as close to $1000-1300 as possible.

Any information you can provide about the ups, downs, ins and outs of Direct Port Nitrous is appreciated!

 

I have installed about 3 of these systems already and I can tell you first hand they are very nice

 

with a DP system i would say a dedicated would be very smart... alot easier to fine tune IMO espcially since i have no clue what to do on a computer EFI car....

plus with your 200 shot youll need some race gas to run it... it say put about c14 in your dedicated cell.

 

I'm hoping that I will not need to run a dedicated system, and I want to keep using pump gas, as well.

Why is it safe to run a 200 wet shot on pump gas, but not safe with a direct port shot?

 

It is safe you just need to adjust the ignition timing accordingly, some people just like the dedicated cell with race gas as an extra precaution

 

I was heading down that path too when I got my FAST...Dave gave me lots to think about..Ex tuning, fuel supply to name a couple.
- Macon

 

Macon - I noticed during my search earlier that you're running a FAST with a wet setup, and I was wondering what your reason was. Thank you for the reply.

Can you go into a little more detail?

The car will be on the dyno getting tuned the first time it sprays - Jeff Creech at Carolina Auto Masters will be handling the tune.

As far as fuel supply goes, I will be running a Racetronix pump setup, but in the interest of keeping the cost low, I'd like to retain the stock lines, rails, etc. Is that not possible?

 

You can run a 200hp on pump gas, but like JnJSpdShop said it will require some addition tuning with the ignition timing. Running race gas (or even alcohol) in a dedicated cell just adds an extra bit of safety and the ability to run more timing. Plus with a dedicated fuel cell you are normally running a pressure regulator with it which gives you the ability to make very small incremental adjustments to the a/f while spraying the car. Just another added bit of tuning ability, which I like.

I would suggest contacting Nitro Dave. I'm sure he would be more than happy to work a deal with you on getting you setup with a beautiful DP system that will perform how you want it to.

 

DP can be a handful, but there should be no problem retaining your stock rails.
I have been "tooling" with mine for a while and finally have it running well. You can run it without a dedicated fuel system, just be ready to spend $$$ on a good regulator; don't go cheap. Also an A/F meter is a must with this type of setup. You need to be able to see/record your A/F to make sure your mixture is good. This is the pain in the *** part of the system, making sure you are running safe. A single nozzle system is much easier, but the DP system just looks SOOOOO COOOOLLLL! Best of luck which ever way you go.

 

For my daily driver DP does not seem to be the answer. I had purchased the NX MAF system for my bolt-on LS1. I did to replace the Zex LS1 system that I simply did not care for. Why is stuff for another thread. When I decided to go with a stout motor, I phoned (Nitro) Dave and discussed my options. I really considered this:

The difference in my 408 and my LS1 requires no dyno numbers to understand. Whatever the 408 dynos out to, and I hope for ego's sake, it's a nice fat number, it is way more powerful and torky than my LS1. I'm going to have a tough enough time hooking up the thing now (Ex. see the start **** thread...it's valid) so I don't need any more than a 150 or 125 wet shot to be satisfied. (At least for now). That meant that I already had a wet kit in my garage that was suited for my needs (and more). My undersatnding is that to get the most out of swapping out parts for the DP, i'd still be best off with a dedicated fuel system, wide band 02 and suitable logger, a less streetable tune (for me) and a lot of plumbing and 16 jets to swap around if I want to change the HP shot. So for me...time, ease of use and money already spent. Again because of money, a new 90 mm throttle body, MAF and 90 mm FAST lid are on my wish/to-do list but not in the near future, so the NX MAF system was still a great choice since I use the stock TB, MAF and FAST. (I'll add that I bought my 78 mm FAST for use on my LS1 and used it on the 408...if I had purchased the FAST for the 408 it would have been the 90mm). Lastly, knock on wood, since I installed Fuel Pressure gauges, Nitrous Pressure gauges, Racetronix FP and a mid sized cam for the 408 with the FM13-114, the motor sucks air big time. I'm not super concerned about puddling. Still my conclusion is that I think a DP system is the way to go wet ultimately; however, I'm real pleased with the NX MAF system based on everything i've seen/read/heard. I'd never try to talk anyone out of a DP system. I would try very hard to help people understand exactly what they are getting in to. I'll agree with the "talk to Dave". {Funny, he's had the opportunity to sell me some big $$ system and he just seems to be looking at more than the $$. You know he'll get my cash, he earned my respect already.} You'll be fast no matter what you do!! I'm sure CAM will be able to tune it up right too from what i've heard. Good luck...i'll be following your progress.
- Macon

 

Joey,
When looking at going direct port there are many things to consider.
The fact that you already do not have a system leaves you with the choice of what is better now and what is better later.

First I always ask the customer to be honest with them selfs. I ask them to ask them selfs how much do they intend on spraying now and later...

While reading this think about where you fit in.

The directport system has many advantages. However it also has many disadvantages.

First the advantages,
The system can easily spray more nitrous/fuel and distribute it better to each cylinder.This comes into importants on shots 250 or above.
With a directport you can indavidualy tune each cylinder.This helps on motors that have a cylinder that runs lean/hotter than others.. LIke the number 8 cylinder on a lt1.

OK now the disadvantages.
The directport system requires more time and money on the system and installation.
The directport also requires more tuning than a average two jet system.
Running a directport on small 100 to 150 hp on EFI jetting makes the fuel jet very small. A simple piece of sand could clog it. (A good filter and clean install should keep this from happening.But it is a possiblity)

ON a stock fuel style system. Even with the racetronix system you may need a fuel accumalter to make sure the fuel supply is there on the intial hit. I have seen some cars need it and some not.The directport requires more fuel at one time. This is why a dedicated system is great. With a dedicated you can also run race gas.

Ok with all the pros and cons out there. Here is what you need to ask yourself. Are you ever going to go over the 200 hp jettings? Is the extra work and money worth the cool sweet look of a directport if you have no intentions of going over 200-250? If you answered yes well then there you have it...

Now keep in mind.The directport really comes into play on about a 250 shot. When you get around that range I like to suggest a directport. Here is why I lean this way. I have ran and tuned many different systems. I like to keep it simple if possible. Moe and I have tuned many directports,many single nozzles,many maff kits, many plate kits, many power ring kits and many dry kits.

Each system serves its time and place. If you do not care for paying for the look and do not think you will ever go over the 200 to 250 range a simple single nozzle plate, or maff kit may do anything you ever wanted to do. With a good tune up the system will give you years of fun just as safe as the directport will. With less hassle.

Sorry to cary this out so far. We all know I love directport systems.We all know we pride our selfs on the plumbing jobs we do. I would love to see a directport on everyones car. However I would also like everyone to know the pros and cons of each way. Some people may be better off with a more simple set up. Some may think they need a direct port when they do not.
I hope this helped.
Dave

 

That was what I was trying to say!
- Macon

 

Very good write up.
Thanks for your time and thought on it.

 

Wow, thanks Dave!

I think I'll stick with a wet setup for now. Later on down the road when funds are more available I always have the option of upgrading. Hopefully the improved airflow that the FAST provides will go the extra mile as far as preventing puddling goes!

Thank you again for all your responses, and thank you Dave for an excellent writeup!

 

You, sir, just saved me quite a bit of money.

 

Here is my N.O.S DP Pro Fogger 250 shot & Fast90mm I done my self.

 

Oh man... Not much beats the look of a nice direct port system. How big of a shot is that? I really would like a DP system but the highest I would want to go would be a 150 shot. So I figure with a solid tune and all the right parts a wet system should get me along just fine.

 

The only thing about going smaller than a 250 shot on a DP is the jet size ,they start getting pritty small and a chance of getting stopped up, even with filters.

 

Would a purge valve fix that if you purged right after your runs? I know that jets get clogged up with small shots but I guess I'm just not sure how exactly. Is it just nitrous being left in the jets after a spray? Or is it other crap getting into there and you not having a big enough shot isn't enough to push it through?

 

It is because the orifice in the jets get so small....for a single nozzle you have 1 nitrous and 1 fuel jet....for a direct port you will have 8 of each jet supplying the same amount so each jet must be much smaller. This increaes the chance of a partical plugging the jet.