High-Tech Nitrous

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Direct Port Dry and Wet

This section is dedicated to the Direct Port style of nitrous. The main section is the How-To style of adding a single plain and some of the hurdles we may encounter. It's not an absolute how-to but rather what we did. Hopefully you can get some ideas and insight. There also is a section dedicated to all styles and methods of doing the Direct Port. There will be wet and dry photos in that section. Here are the direct links to each paragraph, or section.

Direct Links Below:

 

 

Misc Direct Port Set-Ups

I don't have much information on this intake yet, but it was shown at SEMA. With Edelbrock getting into the LSx game we may now have a Tunnel Ram style intake that the mases can afford. No more wishing I had one of the $3000 sheet metal intakes. This will be my next Dry Direct Port set-up, no doubt.

My current Dry Direct Port. It's a Edelbrock Victor Jr. single plain intake. This intake allows the 408ci to breath a little better up top and allows an extended RPM range. I increased the plenum volume a small amount with a Wilson Burst panel spacer. It gives me a piece of mind should we have another N2O backfire. The DP was plumbed and flowed at HSW.

Mike from HSW has this trick 3-stage Dry. More information coming.

Here's a Bad Azz 90mm Beck sheet metal intake running 3-stages of dry.

Here's a HSW painted Fast 90mm with a single stage wet kit.

A 105mm 2-stage wet Beck/HSW sheet metal intake.

Direct Port Dry and Single Plain Intake-Install

This section is a somewhat how-to on doing the "Direct Port Dry" utilizing the Vic Jr. single plain intake. It's closer to how I interpreted installing/plumbing the single plain/DP. This is still a work in progress, so forgive misspellings and things like pictures in random order. We will get things fine-tuned as time allows. So many are asking about this set-up, we figured putting out what was available now would still help.

Why the single plain? Well even though the dry backfires are ultra rare it's just a nice safety feature of the aluminum intake being able to withstand a nitrous hick-up, or backfire. Another motive for me was to get the motor to live in the higher RPM band. The reasoning for me was simple, running a 6-speed and having the rpm drop per shift can have an over all effect on ET. So by going single plain i will be able to extend my usable rpm range and shift a little higher. Then using a Wilson spacer/burst panel this allows for plenum tuning and gains on the top end.

Why the "Dry Direct Port"? Well there are many good reasons for going this route. The new wet vs. dry write-up I am putting together will cover all the angles and I will link to it when it's finished. For now lets just say, simplicity, ease of tuning and the safety factor, which only the dry technology can offer, are amongst a few of the reasons. Really I can not find any good reasons to have fuel IE: atomized gasoline/vapor in the intake on the LSx/EFI platform. If someone can point out a good reason let me know? With the modern electronics available, utilizing the stock PCM/ECM is the way to go. The wet style of nitrous, for the most part, is a hold over of 40-year-old carburetor technology. So why not use the new modern tech of the EFI/LSx and the PCM/ECM to do our fueling and timing pull needs?

I am not going in to the exact how to do an intake exchange. I figure if your interested in the single plain and DP, you probably know how to change an intake out. If not, just get the shop manual for particular car and follow the step by steps. It’s real easy and under an hour job for stock change out.

Here's what it looks like currently. I will be just adding pictures and stating what has been done. This is basically how I did mine, and what you choose to do in the details department will likely be different. But still, you should get some ideas and insight, hopefully.

Here is the valley cover painted gloss black for detail purposes as it can be seen after install. Also I replaced the stock valley cover bolts with SS button heads that I polished.

Here's a general picture when setting up the fuel plumbing. I still may change out the black soft braided hose and go full hard line.

A mock up prior to making the adapter for the bellows. This was made using fiberglass tube stock and cutting 3-pieces at 2x° and then epoxy them together. This way all the stock CAI plumbing still worked after adding the Wilson 1" spacer. If your not using a burst panel/spacer then you will just need an extension and piece of smoth Teflon bellows.

The bellows adapter being test fit. We are using the stock bellows, however we will change that out in the near future. Still, with this adapter it is all plug and play concerning the intake tract forward of the TB.

Here's a shot that HSW took at their shop. Very nice welding on the bungs. Notice how I used the polished button head machine screws for detail work.

Here's a side shot showing the "Y" block and one of the solenoids. This "Y' block allows the line lengths to remain the same, and this in turn allows the N2O to reach each cylinder at the same time. Something else to note, big solenoids are used, no little weak ones here. I have had way to many problems with the little solenoids not opening due to heat sink and being under powered. These solenoids use more amps and thus can overcome any engine bay induced heat. There is one per side. I may add one large solenoid as a safety solenoid should either solenoid fail or stick open. This way one single very large solenoid will still shut the system down should there be an issue. I have been looking at some 500/700hp N2O solenoids for this purpose. The single solenoid would be at the end of the 6an-supply line then "Y" to each solenoid that controls individual banks.

Another shot of the "Y" block after early on install. Notice that the fuel fittings are a full flow sweep style 90°, or often referred to as tube 90°s. These two fuel lines going into the regulator are the cross over lines. The fitting out of the bottom of the regulator is the return and goes directly back into fuel tank.

A close up of the beautiful welding, a pro job no doubt, which is very important on a set-up like this. I didn't want to just drill and tap the intake manifold, so went the extra dollar route of welded bungs. Your choice though as this can save a bundle. Something to note if you choose to drill and tap your own intake, you will still need to get it flowed. Flowing allows for all cylinders to get the exact same amount of nitrous. You wouldn't believe how much the cylinder to cylinder difference can be on an UN-flowed intake. Not flowing will cause a/f ratio per cylinder to be off and that can lead to less than optimum "Volumetric Efficiency". That’s one of the reasons to go DP, whether wet or dry, to get all holes the same and thus a high VE.

Here's one of the nozzles, notice no protrusion into air stream, much more efficient than most DP Wet nozzles that stick out into the air stream and become restrictions and disrupt air flow. Also, in this optimum location it aims directly at the intake valve like it should. No wonder the Dry Direct Port has close EGTs (temps), per cylinder, compared to many DP Wet hits that just randomly spray fuel and n2o some where down the runner towards the combustion chamber, and that will not be very "Volumetric Efficient, work yes, but not optimum. Reading the plugs, reading a/f ratio per cylinder and/or reading EGTs we can see proof that the DP Dry can be easier to tune. Seems that once the initial set-up has been flowed and then put into real world use, the Wet DP often needs further individual cylinder tuning. Where as, the Dry DP will have cylinders much closer to each other and normally need no further individual tuning.

Here's the Wilson Spacer/Burst panel at 1¼" tall. Burst panels can't be seen in this picture, however, there are three per side. Here we are making our own gaskets to fit after cleaning up the plenum. Also, the Wilson spacer comes drilled for pinning, which I have done. This way we get the spacer and elbow exactly in place each time with no protrusions in the air path. This stuff takes more time but is the correct way to get the best VE over all out of our engines.

Here's a look at the carb opening being cleaned up.

Here's the tab I welded onto the elbow for the regulator mount point, and the spacer below. I like the way this turned out, however, in my fuel system write-up we talk about other ways of doing this. Many options are out there for plumbing this stuff , that's for sure. I saw this style in one of the threads, or least a similar style and decided I like it so went this route based mostly on looks.

Here's the "Interface", the controller that allows the Direct Port Dry to be run with the stock PCM/ECM, a plug and play device. This was not possible a year or two ago. An after market ECM was needed. So the low dollar Interface allows full control of fueling needs along with timing pull needs while spraying only. This can all be done with out the need of a laptop or tuner program. Now with said, if you have a tuner program already, then the advanced features can be used. More on the Interface in an up coming write up. This is one of the innovative products that the dry camp has been waiting on. We are also no longer limited on injector size as was the case a year ago. Racetronics has released a 80lb injector compatible with the stock PCM/ECM, no more need for after market controller and driver package for going big with the injectors.

Here is the rear cross over line. I just used two 1/2" "T"s that allow each of my fuel pumps to enter. Pump #2 only comes on when the spray is activated and at 3200rpm. That way we are not constantly running the pump and heating up the fuel when not needed.

Here is the adapter fitting which was just cut off an old stock fuel rail. This is used inthe next picture.

Here is what the stock lines look like with the AN adapter fittings installed. Now we just make up some jumper hoses that route up and behind the brake master and it's all hidden and out of site. Ther is one more line that is not in this picture, two pump supplies and one return.

Bad picture, I know, lol. here is where we can get into trouble on the C5 platform. The drivers rail is real close to the firewall. what i did was to cut off some off the end then use a hard 90° fitting. Using a hard 90° is not the best fitting to use, however, I went up one size to negate any flow restrictions and now have the clearance needed.

Here's the fittings installed at the rear of the intake prior to cutting drivers rail. It would not fit with out triming the rail down. The return fitting can be seen on the bottom of the regulator.

Here is the MAP sensor relocated to the rear intake bolt along with a Vacuum "T".

The vacuum source on passenger side, and a good view of one of the solenoids mounted to the "Y" block.

Here's the stock LS6 intake after a 300rwhp high RPM lean back fire. This is one of the reasons I went with the aluminum single plain, but not the sole reason. I believe had this been a wet hit, that had the added fuel and/or vapor in the intake tract, the fuel rails would have likely been dislodged due the a much more violent explosion. Then we could have had the dreaded engine bay fire. Back fires are few and far between, but they can happen, however, with the new dry tech much, much less often. Actually, besides this intkake here, there is only one other confirmed dry backfire that we know about with the LSx platform.

Here's how one of the after market elbows fit. We could shut the hood, however, this caused a bulge. I am having some custom elbows fabbed up that will work with the stock hood and flow better than the current model. that is clay you see on top of the elbow. The black circle is where it was hitting and actually transfered paint. I now have the 1¼" spacer below the elbow, so an after market hood is my only recourse.

EDIT: We have converted to an engineered cast elbow from Edelbrock.