How safe?

[NickT'sGTP]

How safe is it to shoot a 75 hp Wet shot through a roots supercharger? I've heard horror stories about how the supercharger can backfire, and blow up my whole entire topend. This is why I've been leaning more towards a dry shot. :wiggle:

But if for some odd reason further on down the road, if I want to do something larger than a 75 shot, I would need a wet setup right? Lets say a 100 hp shot, or a 150 hp shot. It'd be easier to have a fuel solenoid also shooting in the right amount of enrichment fuel correct? Otherwise I would have to rely on something increasing the fuel pressure, or some type of tuning to increase fueling.

I have a 1998 L67. It's a 3.8L V6 with an Eaton M90 supercharger on top, pushing in about 12 psi of boost. I'm upgrading the fuel system before I install the nitrous. I'll be putting in Lucas 42.5# fuel injectors, and a racetronix fuel pump. Right now with my OEM pump (93K miles) I'm seeing 60 psi of fuel pressure at WOT.

:hmm: Would a dry kit be safe for now?

[Mustang Boy]

what kind of pistons do you have

[NickT'sGTP]

Diamond brand pistons. Forged, .020" over bore, stock compression (8.5:1), and a ceramic coating.

[Mustang Boy]

ive heard some bad things about spraying through a blower but that is only if it puddles but i also know quite a few people who have sprayed through them with no problem so i dont think a 75 shot would hurt anything as long as it doesnt puddle

[NickT'sGTP]

ive heard some bad things about spraying through a blower but that is only if it puddles but i also know quite a few people who have sprayed through them with no problem so i dont think a 75 shot would hurt anything as long as it doesnt puddle

Would a 75 shot dry be okay?

[srsnow]

Do you have one of the supercharged Pontiacs? On some of the blowers that were designed for EFI applications there have been cases where people have put fuel through them and they have had problems with the cases cracking or other issues caused by the screws in the blower not having the clearance needed to deal with gas. However I don't know at what HP level this became an issue. The NOS dry kits have been put on the S/C Pontiacs with good results for many years now so that would be my suggestion assuming your car still has the right fuel system. But in general supercharged cars responded very well to nitrous usually making more power than advertised due to the added intercooling effect of the nitrous.

[mrr23]

i'm not a fan of running fuel through a blower. the blower compresses the incoming air via the rotors. now, add a liquid that doesn't compress easily and this is where problems can occur.

[bleu]

i think a 75 shot would go fine in the short term. but I would not put it under the heaviest loads.

To be honest, I just don't know for sure. If it were my car, I would go with a direct port setup because the extra cash is worth it in the long run if you blow it.

[NickT'sGTP]

Do you have one of the supercharged Pontiacs? On some of the blowers that were designed for EFI applications there have been cases where people have put fuel through them and they have had problems with the cases cracking or other issues caused by the screws in the blower not having the clearance needed to deal with gas. However I don't know at what HP level this became an issue. The NOS dry kits have been put on the S/C Pontiacs with good results for many years now so that would be my suggestion assuming your car still has the right fuel system. But in general supercharged cars responded very well to nitrous usually making more power than advertised due to the added intercooling effect of the nitrous.

yeah I've got a 3800 Series II Supercharged, with the roots Gen III Eaton M90 supercharger. I'm currently running 12 psi of boost. My fuel system is still 100% stock other than fine tuning within the PCM. (Enrichment fuel, and burst fuel....etc....) I was going to initially go with a Dry Kit from Zex. But it seems like there's so many to choose from, I don't really know what to do. :dunno:

i'm not a fan of running fuel through a blower. the blower compresses the incoming air via the rotors. now, add a liquid that doesn't compress easily and this is where problems can occur.

I'm not really a fan of it either. I've heard too many stories of the s/c backfiring, and igniting all that fuel. That's the last thing I want to have happen.

[hammered54]

both SRSNOW and MRR23 are both right on the$$ with this one ,could cause those problem for sure, so the ticket is to put the juice past the rotor's so the fuel is on the bottom side and no2 is on the top side, you get the add'ed bennifit of also cooling the charge and packing that windmaker with more oxygen, but start small and watch you timing or you'll drive right over that crankshaft, but other than that sound's like a great idea

[NickT'sGTP]

both SRSNOW and MRR23 are both right on the$$ with this one ,could cause those problem for sure, so the ticket is to put the juice past the rotor's so the fuel is on the bottom side and no2 is on the top side, you get the add'ed bennifit of also cooling the charge and packing that windmaker with more oxygen, but start small and watch you timing or you'll drive right over that crankshaft, but other than that sound's like a great idea

My normal timing advance right now is right around 18-19*. Would bumping it back to 14* at WOT work? I'm going to start off with a 55 hp shot, and scan it. See how it goes, and if possible keep jumping up shots depending on how well the scan goes.

What type of a/f ratio is good for a dry nitrous shot?

[hammered54]

try this, make one pass and if don't rattle use it for your starting point, now retard it 1or 2 deg. if mph pick's up good, retard it 1or2 more if it pick's up again your on the right track do this till mph drop's off go back to previous timing , maybe one less for a cushion, check plug's (all of them) should look like new with no bluing on the strap( if jetting is corect) adjust fuel pill till this happen's, if you up the no2 pill start rechecking plug's and timing, about 2deg. back +/- for every 50hp gain,

[bleu]

try this, make one pass and if don't rattle use it for your starting point, now retard it 1or 2 deg. if mph pick's up good, retard it 1or2 more if it pick's up again your on the right track do this till mph drop's off go back to previous timing , maybe one less for a cushion, check plug's (all of them) should look like new with no bluing on the strap( if jetting is corect) adjust fuel pill till this happen's, if you up the no2 pill start rechecking plug's and timing, about 2deg. back +/- for every 50hp gain,

Can you break this down for me? I don't understand.

So, your saying, with the S/c and N2O do a run. record the results assuming it doesn't rattle (knock?). If it is good then retard the timing? (why? when you retard wouldn't he lose power?) run again if you see more speed...


I belive you i just don't understand it. It seems backwards to me. Wouldn't you retard it a degree or 2 just to be safe from knock?

sorry,

Thanks

[NickT'sGTP]

I agree with bleu. I think you're saying, if I make a run down the track with the 14* timing, and I don't get any Knock, and the MPH (trap speed?) picks up, then retard the timing 1 or 2 more, and up the Nitrous?

For the plugs, I'll be using Autolite 103's, copper core, at a .040" gap. Right now without the nitrous I'm using AL104's copper core, at a .050" gap.

[hammered54]

the point is to find the correct timming, if you start at 14 and you back off to 12 and it pick's up MPH you are going in the right direction, if it ping's or rattle's( assuming you have good gas )go back in the other direction till you have your fastest run, then that's where it stay's (for that no2 setting) change the shot change the timming it's that simple, also you are correct drop to a colder plug w/no2, more no2 colder plug, more no2 better gas,
bleu, the higher the cyl. press. the less timing you need to burn the charge, also better gas is required for the higher setting and cooler plug's with small gap's, more no2 higher cyl. press. less timing. any ??

[NickT'sGTP]

the point is to find the correct timming, if you start at 14 and you back off to 12 and it pick's up MPH you are going in the right direction, if it ping's or rattle's( assuming you have good gas )go back in the other direction till you have your fastest run, then that's where it stay's (for that no2 setting) change the shot change the timming it's that simple, also you are correct drop to a colder plug w/no2, more no2 colder plug, more no2 better gas,
bleu, the higher the cyl. press. the less timing you need to burn the charge, also better gas is required for the higher setting and cooler plug's with small gap's, more no2 higher cyl. press. less timing. any ??

Gotcha. do you suggest I start off at 16* and keep working my way down? Or is 14* a good starting point. normally what does a 55hp shot do for a 1/4 mile? Let's say I run low 13's, and low 100's trap....what will a 55hp shot add?

[hammered54]

do you drive this as an every day ride? if so I would get a timing control box ,like the MSD 8970,8972,or something like them, that way you can keep your stock timing for every day life and when you step on the gas this automaticly retard's it your no2 setting, it's so ez you just pull chip's in an out till you end up with what you need for you best MPH and leave it !! go pick up MSD's wiring diagram's and tech note's it's only $5.00 !!! it will show you how to wire ALL of there eguip. into a killer no2 system, good luck

[NickT'sGTP]

yeah this will be an every day driver. I've been looking into the MSD Window Switches, but never really heard anything about a timing control box. I'm going to invest in a tuning/scanning software to install onto a laptop. Either DHP Powertuner, or HP Tuners VCM Suite. That way I can retard the timing at the track. I won't really ever use the nitrous except for at the track, and maybe the occasional street race. But I don't ever race anyone from a light. I'm a paramedic, and If I get my license pulled, my career is over.

thanks for the advice, and i'll look into the MSD timing control box.

[kadett-c-coupe]

use google for nitrous blowerplate. you will notice the blowerplates are a rather simple design, you can probably make one like that yourself to instal under your current supercharger

[evilbeef54]

i use an msd digital 6 plus box, it is super easy to use, i set my timing for everyday driving and there is a dial you can adjust to retard timing whenever the n2o selinoid hits, no pills to change/loose just a dial to turn, and you car will always run with your "street" timing untill the n2o hits

[johnnye]

im new with nitrous with my l67 to the only way i see to adjest timing on the fly would be this http://intense-racing.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=IR&Product_Code=3800-CAS-CTC-033&Category_Code=IE

[Robert56]

im new with nitrous with my l67 to the only way i see to adjest timing on the fly would be this http://intense-racing.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=IR&Product_Code=3800-CAS-CTC-033&Category_Code=IE
Yes, that is one way to do it. I also carry that product.

For those reading along, be carefull on running the most timing for the most power. That is not always the best way to tune for a street/strip car running pump gas. The reason we pull timing on the spray is to get the combustion taking place back to a safe point. Now if your NHRA bound, yes time for max power. be carefull on the timing with blowers. less is sometimes safer, and if you want more power, add a bigger jet.
Robert

[johnnye]

what is another way to change the timing on these computer control cars ?

[Robert56]

There are few controllers here, for insight (link #1). You can even do it in the tune when running a before the MAF style dry hit like the NOS 5177 kit (link #2); or you can wire a resistor into your IAT, which there is diagrams how-to on my site under nitrous wiring, and it's only cost a couple bucks (link #3).

http://www.robertsnitrousservice.com/electronicswebstore.htm (http://www.robertsnitrousservice.com/electronicswebstore.htm)

http://www.robertsnitrousservice.com/drytimingpullwriteup.htm (http://www.robertsnitrousservice.com/drytimingpullwriteup.htm)

http://www.robertsnitrousservice.com/nitrouswiringschematics.htm#176297805 (http://www.robertsnitrousservice.com/nitrouswiringschematics.htm#176297805)

Robert