OK I have an Automatic 2001 C5 Vette. Patriot Heads, 228/.588/114LSA Cam, 3.42 gears, RPM Tranny, NGK BRE7EF Plugs (just put in), Yank SS3600 Torque Converter (2.5 STR), Not cats, KOOKS headers, NX Dual Nozzle Wet Kit. , MDS Window switch, TPS sensor (WOT switch), Fuel Pressure Safety switch. TNT Power ringetc etc

RAN N/A first just to check tune and the got 370 RWHP and 376 RWTQ (Converter was UNLOCKED).

OK first of all we put #35 N / #18 Fuel. Didn't make 100 rwhp but made close to that torque. Only wanted 100 shot but they guy who is well versed in nitrous said 150 was fine. Put in #41 / #22 (About 150 HP, maybe more cause of the dual nozzle). The tune was fine and timing was pulled air fuel was fine as well and duty cycle of STOCK injectors was at 93% (checked in on the dyno). Stock Fuel pump was fine, if not would have upgraded and still might eventually.

Notes to be aware of:

- Tech Unhooked or bypassed the Fuel pressure Safety Switch. Said many times they cause problems and my car has a WOT switch and window switch so I should be OK.

-Ran the Yank SS3600 Torque Conveter UNLOCKED

- Window Switch was at 3600 ON and 6400 OFF

-On the N/A Run The YANK SS3600 didn't seem to drop in power or slip like I am about to talk about in the next section (look at my DYNO I am not an expert).

-NA Dyno 369 RWHP / 376.6 RWTQ

-150 Wet Shot Dyno 458 RWHP / 540 RWTQ

OK The Issue

There was something strange that happened on the dyno. You could HEAR the car do it (drop off for a second) as well just like the dyno shows around 4,500 RPM's. I just have this one printout so some of what I say below is from memory.

First of ALL it didn't make 100 RWHP, but made 164 lbs of RWTQ.

Also on the DYNO The Nitrous HIT really hard and Then all of a sudden around 4,500 you could HEAr it and see it on the dyno it FELL OFF for a bit (almost like the nitrous shut off) and then climbed back up. Also toward the top of the run it was making only about 60 rwhp. COULD the CONVERTER Be SLIPPING????

They couldn't figure it out and there were 2 guys that knew nitrous well and tuned many cars.

THEY SAID they were thinking ]that my CONVERTER was too loose or maybe was slipping. Also he told me to go run the car on the street and see if it did the same thing because sometimes the LOAD of the DYNO reacted different than it would on the street in actual conditions. I HAVE NOT had the chance to run it yet and will tomorrow. He said if it happened I would feel it hit and throw me back in the seat and then it would stutter for a second and then pick back up and pull........

One guys said He thought it COULD be my Valve springs?? The extra nitrous power was too much for a failing spring, or maybe one of my duals is broke?


Do you really think it could be my CONVERTER?? The increae in HP and TQ was too much for the converter to handle and caused this to happen? I wonder how to check this?

Is it just the DYNO and maybe it will be OK on the street?

Do I need a TIGHTER Converter? I thought a YANK SS3600 was a decent nitrous converter? Maybe 150 is too much for it?


Do you guys think it is something else? Could it be the bypass of the FPSS (they said that shouldn't matter at all). They checked my jets and I have a GREAT nitrous filter and they checked that. Said it wouldn't hurt anything, but they didn't know what it was and the guess was the Converter.

Here is the DYNO. Let me know if I need to post anything else?

Again, it bugged me because it isn't perfect. I mean the nitrous is working because look at the TQ! I hate to get a new TC andthat NOT be the issue.

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Any help by You guys is appreciated!

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Also another post I found seemed to be having the same issue on a Mustang I will post what they said below and this is similar to what I AM DEALING WITH......

http://www.allfordmustangs.com/forum...n-nitrous.html


"A friend of mine just installed a 75 shot of Zex Nitrous in his 2003 Auto GT. He took it to the dyno the other day and the Nitrous keeps on slipping on him. The dyno keeps reading thats he is jumping from 260 HP to 300 HP. Its as if the Nitrous is being fed to the engine for only a second, letting off, then coming back again. Does anyone have a remedy for this situation? He was on another mustang forum and he was told that if his HP exceeds a certain amount with an Auto tranny then he needs to buy a tourqe converter. Is this true? Thanks for any information guys"
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Thanks again!

 

do you have a purge on the nitrous line?? ive ran into problems where i didnt purge all the air outta my line and you can here and feel it that the car looses power... next run i purged the hell outt of it and made sure my line pressure was at 1000psi(Where i jet mine at) and it was flawless. ive ran into that problem before.... nitrous is kind of a touchy thing to use!

 

thanks but did that

 

doubt its converter. the ss36000 is a good converter for the spray. Any scanning while this happened to see if anything odd appeared? Also I found my old TNT jet chart, and 150hp is 42N 25F

 

Yeah not sure it the converter either BUT it could be sliping. I have a BEEFED UP tranny so I doubt it is the Tranny. Obviosly something is happening when the spray is ON, seems to be a mechanical issue, but only when we spray, NOT NA.

The guys did say 1st, TAKE her out and trun it on the street and see if it does it again, they said you will FEEL and see the exasct same thing as ther dyno shows, hit really hard, then fall off....


YOU could hear and feel it on the dyno, HIT Him really hard like in the dyno graph, then all of a sudden fell off (but the nitrous was still on). One guy sthought it was the Torqe Converter slipping one didn't think it was that but wasn't sure what it was. he said something was strained on the N2O? He even mentioned valve springs possibly not being able to keep up when the nitrous hit? Just an outside chance, but just mentioning it. Again NA it is Fine!

I am running a dual nozzle NX Wet Kit, but use a TNT Power ring so the jetting for TNT is not what I'm using. Thanks

 

Sorry, but I didn't see the results in your first post. How did it do?

 

Do at what? Sorry short... Not sure what you were asking. Just dynoed a few times. Haven't ran on street YET! It might just be slipping on the DYNo and the load is different on a dyno, now I think it could do the same thing on the street, but I am hoping for a miracle and it works fine.

 

When you posted "you did that" after my first post, I thought you were referring to already taking to the track. No biggie.

 

See how much power it makes at the lean spike?

Then as to much fuel sets in the power decreases. its rich!
You can prolly hear the car bog down.

If you guys knew how to read plugs and just used the plug reading and the HP numbers you would be amazed how much faster your cars would be.(not aimed at you personally just a general statement)

 

It was fine on the NA, look at teh A/F line below the spiked run, it is smooth and straight.

Also can you guys PLEASE confirm, someone, They Bypassed my NX Fuel Pressure Saftey Switch because the tech said there is always issues. Now when he did this, he took OFF one of the connectors that were screwed to ONE the side of the FPSS and put it on the otherside of the FPSS, on on one side of my FPSS there is BOTH little circle connectors that are kept in place with a screw and on the other side of the FPSS ther eis nothing connected. Is this correct and from the dyno is there anyway it could be a FPSS?

 

looks like your bottle pressure fell off

 

Looking at the graph its hard to see. What is the actual airfuel across the board? What was the bottle pressure at the end of the run?

Personally I always use the fpss safety switch. The reason some people complain about them is because they do not understand how to adjust or set them. They serve a purpose and alot of times when people think they are a problem it was because they were doing the job they were programed to do.

However that is not why your not making the power you should be.
Dave

 

Thanks any other ideas guys? I am getting something cause the torque is OVER 15 when it hits..

Hmmmmm

 

What is the actual airfuel across the board? What was the bottle pressure at the end of the run?

 

not sure about bottle pressure, sprayed at 900-950. A/F I need to look at the actual computer graph again. the printout looks bad as you saw

 

I FORGOT. One guy at the shop said he thought it might be the VALVE SPRINGS!

The addition of the nitrous put additional strain, maybe one is broke? I have duals.

Then in another post another guy said VALVE springs were HIS issue. They tuned it for a long time and finally the guy said it is the valves, check them. One was broke. Not sure, but mine have 20K so it is time. Patriot Dual Golds???

 

I had five broken springs, last year, I was not spraying it during that time because I knew something was wrong. Does it do it NA? You getting a misfire code from time to time? ECS checked everything but the springs, tried new coil packs etc...I later checked the springs, and found five busted.

Jim

 

NA Dyno WAS Pefect. ONLY did this on the 100 and 150 nitorus run.

No Misfire codes at all. But again it only did it on the Nitrous. I might have a broker spring, OR maybe one is starting to loose integrity and going bad, have 20,000 miles on them and the additional load of the nitrous might be causing an issue. not saying that is it, but the one guy said he thought it might be blowing past my YANK SS3600 converter. I doubt it is that, but you never know.

Here is the graph again. A/F was also straight with N/A run. Both A/F and Dyno Graph BOTH had that hill and then dip where the converter kicked in and the nitrous came on hard, then fell off. Hell on the 150 N2O run my PEAl Torque was High, so I knwo it was working for a bit. This one guy that knows his stuff said, man I bet it is a valve spring issue.

 

Call the dyno shop and ask if they can print up that same run with seconds as the x axis instead of RPM's. It looks like transmission slip to me, but you could check that if you see the rpms shoot up on a time based graph.

Or see if they can graph your overall gear ratio across that same dyno pull. That would definetly show you if it wasa slipping or not.

I'd be suprised if its valve springs. You wouldn't see hp drop, it would just flatten off instead, and that usually happens at a higher RPM.

 

Cool. Thanks. Have beefed up RPM Tranny so I doubt it is the tranny. Never had an issue with it, but I see what you mean on the valve springs, BUT who knows?

Just need to get that done anyway to be safe and it is time