Nitrous
- Thread starter Razor
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I say, Yes.
No actual documentation on turbos but on NA cars the motor can be designed with N2O in mind (cam, heads, intake, etc) and make the N2O work more efficiently so a 200 shot could give 300 at the flywheel. Hot Rod proved this many years ago where an extra 200 shot made 500 extra HP. I would certainly think a turbo would have the same type of returns as long as the turbo wasn't too small or the shot too large. However, the turbo could be the bottle neck with the exhaust if a large shot was used on a small/restrictive turbo. The unkown part would be comparing the HP gains and the torque gains. The HP may not be 200 HP but, IMO, the Torque would be greatly increased.
OR another way to think about it, IMO, is that it would only take a 125Hp shot to make the 200HP.
ks
No actual documentation on turbos but on NA cars the motor can be designed with N2O in mind (cam, heads, intake, etc) and make the N2O work more efficiently so a 200 shot could give 300 at the flywheel. Hot Rod proved this many years ago where an extra 200 shot made 500 extra HP. I would certainly think a turbo would have the same type of returns as long as the turbo wasn't too small or the shot too large. However, the turbo could be the bottle neck with the exhaust if a large shot was used on a small/restrictive turbo. The unkown part would be comparing the HP gains and the torque gains. The HP may not be 200 HP but, IMO, the Torque would be greatly increased.
OR another way to think about it, IMO, is that it would only take a 125Hp shot to make the 200HP.
ks
My thoughts would be the turbo compressor being the bottle neck. The hypothetical is you have a turbo that can flow 600 CFM's. If adding a 200 shot, doesnt that mean another 200 CFM's of air bringing the number to 800 CFM?
So can a stock turbo/gt3255/ta49 be taken to 800 RWHP with nitrous. I know the exhuast housing is not the restriction..Since for example TSM cars use a .63 as well.. but.. well actually it is come to think about the diameter of the hole where the wheel is creating the restriction....
I'm kind of thinking its not possible due to restrictions on diameter of holes in the turbo to flow sufficient airflow to support the HP.
The other way around, you have a turbo capable of 900 HP. You run 600 HP at X PSI.. you can run a 200 shot and bring the HP to 800 HP since the turbo has the ability of moving the extra volume of air through both its intake and exhaust. This to me would make sense, first scenario I dont think will work.
It may be easier to attain the limits of a turbo using nitrous, but not exceed the flow capabilities of the engine in question by much.
On an NA application they dont have the bottle neck we have by placing a restiction on the in/out of the engine.
Ideas?? Kevins thanks for responding..
So can a stock turbo/gt3255/ta49 be taken to 800 RWHP with nitrous. I know the exhuast housing is not the restriction..Since for example TSM cars use a .63 as well.. but.. well actually it is come to think about the diameter of the hole where the wheel is creating the restriction....
I'm kind of thinking its not possible due to restrictions on diameter of holes in the turbo to flow sufficient airflow to support the HP.
The other way around, you have a turbo capable of 900 HP. You run 600 HP at X PSI.. you can run a 200 shot and bring the HP to 800 HP since the turbo has the ability of moving the extra volume of air through both its intake and exhaust. This to me would make sense, first scenario I dont think will work.
It may be easier to attain the limits of a turbo using nitrous, but not exceed the flow capabilities of the engine in question by much.
On an NA application they dont have the bottle neck we have by placing a restiction on the in/out of the engine.
Ideas?? Kevins thanks for responding..
The extra cfm is coming from the liquid N2O so it's not passing through the compressor housing so i don't think this would be the bottle neck and the compressor could still be flowing the same amount of air. However, the exhaust volume has increased and would need to be delt with so it doesn't become the restriction. But if it does become a restriction I think the n2o would have created so much more HP/torque at the lower RPM that the desired 200 would still be obtained although at a lower RPM (more torque plus more HP). There may be a trade off depending on turbo and how much N2O. Maybe a spraying 100 shot can give the extra 100HP but if spraying 250 you will only get 175 which would show a restriction somewhere.
The CFM rating of turbos, is this the compressor side or the exhaust side or combo of both?
ks
The CFM rating of turbos, is this the compressor side or the exhaust side or combo of both?
ks
This is the question, adding air may be easy.. getting it out.. thats the problem. Hole on stock turbo exhuast housing is very limited. Maybe with an external gate setup that can be better setup, vs the small puck hole that has the flapper.
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Yeah, I have a car with an external gate that dumps behind the DP. That in theory should solve that problem.
This is an interesting topic btw:biggrin:
Id think you would be able to push it over the hp rating a little but not the full 200. Id be willing to bet the torque would be outrageous but the exhaust side of the turbo would choke the hell out of the engine at higher rpm. Exhaust pressures would be very high. You could get away with a huge housing A/R over 1.0-1 and still spool it. You would actually need a hybrid with a big comp wheel and smaller compressor to maximize hp with the N2O. You are limited if you run a 3 bolt housing. A tangential 4-bolt housing with a big A/R would work well though. You will need a bigger much bigger wastegate if the housing is not sized properly.
Starting to sound like if you built it with nitrous in mind.. the flow of the turbo has to be calculated and the sweet spot for its air flow as well.
My thoughts are you get lets say a 76 GTQ rated at ~950 by Precision. If you had a motor at 650 to the wheels at 25 PSI boost.. and you bumped in a 150 shot.. that should take you to ~850. At 25 PSI boost. Vs going to ~mid 30's for boost at ~800.
I did a little nitrous testing on a 35 shot early last year. a 35 shot=60 rwhp. My engine at the time at 27 PSI made 548. At 25 PSI and 35 shot made 585. Two less PSI, made more power. Turbo I was using was a small shaft 67. Rated at ~700HP. These ratings are flywheel per mfg. So 700x.8(20%loss)=560 approx. Pretty much in the ballpark.
When you crank the HP up.. the exhuast flow will increase.. so if you have the exhuast/WG/DP to handle the flow.. turbo to handle it.. I cant see the negative?
Thoughts..
My thoughts are you get lets say a 76 GTQ rated at ~950 by Precision. If you had a motor at 650 to the wheels at 25 PSI boost.. and you bumped in a 150 shot.. that should take you to ~850. At 25 PSI boost. Vs going to ~mid 30's for boost at ~800.
I did a little nitrous testing on a 35 shot early last year. a 35 shot=60 rwhp. My engine at the time at 27 PSI made 548. At 25 PSI and 35 shot made 585. Two less PSI, made more power. Turbo I was using was a small shaft 67. Rated at ~700HP. These ratings are flywheel per mfg. So 700x.8(20%loss)=560 approx. Pretty much in the ballpark.
When you crank the HP up.. the exhuast flow will increase.. so if you have the exhuast/WG/DP to handle the flow.. turbo to handle it.. I cant see the negative?
Thoughts..
Agreed. I would have like to have seen how much you would have picked up on top of the 27psi boost with the 35 shot. Id think youd still gain more than the rating but it would hit a wall at a certain point if the exhaust pressure got too high. I wonder if you would have got 60 more rwhp on tp of the 548? With your thoughts with the 76 GTQ i dont think it would matter as much until you wanted to get more than the rated hp. Though we know those numbers are usually a little high. I think it just matters how much oxygen and fuel you can cram in the cylinders and be able to get it out.
True, but at what point does the exhuast housing on the turbo become the bottle neck.
Guess it starts feeling like a nitrous engine on an NA. Whereby the cam selects airflow though it.. and a nitrous motor, run NA doesnt run well. Guess the same can be said of a turbo engine, but playing with multiple power adders.. gets tricky.
Wish I had more dyno time.. this new motor has a 71GTQ .85 housing. We'll see how the engine breathes it.. and start the datalogging process..
I agree 100%. I think you could go with a larger exhaust housing and/or WG to keep the restriction to a minimum and have great results. The n2o on the line will still spin the larger wheel so this shouldn't be a big issue.
I don't think you need to worry about matching the compressor wheel since you can play with the amount of n2o to gain the power you want unless you wanted to limit your n2o to a certain pill size but max out the turbo design itself. As you may know a lot of the foreign crowd will spray a shot just to spool big turbos on small motors while on the line connected to a window switch then turn it off at a preset rpm. You may consider this idea if you haven't plus this could be easier to tune.
ks
I don't think you need to worry about matching the compressor wheel since you can play with the amount of n2o to gain the power you want unless you wanted to limit your n2o to a certain pill size but max out the turbo design itself. As you may know a lot of the foreign crowd will spray a shot just to spool big turbos on small motors while on the line connected to a window switch then turn it off at a preset rpm. You may consider this idea if you haven't plus this could be easier to tune.
ks
I think its a bottleneck without N2O. Maybe we will have to experiment and find out. It appears theres a lot to be gained form the tangential 4 bolt over the 3 bolt design on engines making 700+ hp. Put some probes in your exaust and monitor the pressures under different conditons. Low pressures+high boost+rpm+N2O=big power. It also means that the crank will be bouncing around if there is any detonation at all. Not even a tiny bit would be tolerated without breaking the bottom end. Some of the turbocharegd 4 cylinders have posted lower exhaust pressures at WOT than the intake pressres. The same is achievable here with the correct housing and A/R. No doubt spool is sacrificed but these are all out race engines that often use nitrous to spool.
quote "I did a little nitrous testing on a 35 shot early last year. a 35 shot=60 rwhp. My engine at the time at 27 PSI made 548. At 25 PSI and 35 shot made 585. Two less PSI, made more power. Turbo I was using was a small shaft 67. Rated at ~700HP. These ratings are flywheel per mfg. So 700x.8(20%loss)=560 approx. Pretty much in the ballpark."
Question? When you added the 35 shot was your turbo boost set for 25psi?
i.e. did the 35 shot NOT raise the boost any? Usually when you add nitrous the boost will go up UNLESS your boost controller backs off the turbo output.
If your 35 shot did raise the boost say 1psi and the controller backed off the turbo the same amount (1psi). Then 25psi+35 shot should be say 26 psi and the nitrous allowed the engine to make more HP than just turbo boost along.
Hope that you are following my logic.
Gary
Question? When you added the 35 shot was your turbo boost set for 25psi?
i.e. did the 35 shot NOT raise the boost any? Usually when you add nitrous the boost will go up UNLESS your boost controller backs off the turbo output.
If your 35 shot did raise the boost say 1psi and the controller backed off the turbo the same amount (1psi). Then 25psi+35 shot should be say 26 psi and the nitrous allowed the engine to make more HP than just turbo boost along.
Hope that you are following my logic.
Gary
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There's one thing you need to be careful of.
When you run N2O with boost, there is a chance of over speeding the turbine wheel due to the excess exhaust flow created with the N2O. This is another reason why it is so critical to run a larger than normal external wastegate mounted before the inlet of the turbine housing. In the Import world, especially the Supra guys, they typically run a large turbine housing A/R and either spray off the line to spool up, or spray the entire run to make more mph and keep the huge turbo spooled up between shifts. I know Boost Logics record setting Supra ran a GT4788 turbo with the largest housing available (1.08 A/R T5 style housing) and a 250 hp shot of N2O that was run during the entire run. This car also ran a best of a 7.86 @ 186 using this method. What I have seen in my years not only with PTE but friends experiences in the past, the turbo will always be the bottle neck, due to not only the turbine housing discharge area (how large of a discharge on turbine housing) but also what the turbine wheel can safely handle. If the turbo is rated to support say 900 fwhp, this would typically be at round the 30-32psi or at the point that back pressure would exceed the 2:1 ratio. With regards to back pressure, the general rule of thumb states, Whenever your back pressure exceeds the 2:1 ratio (Ex: 60 psi of back pressure measured just before the inlet of the turbine housing vs 30 psi of boost measured at the discharge of the compressor cover) the turbine wheel is either out of it's efficiency range, or the turbine housing is too small. I've seen huge gains in hp, sometimes over 100hp in full blown racing applications, by simply stepping up the size of the turbine housing. This is where some have gotten into trouble, either they run too much N2O & over speed the turbine wheel, or the back pressure builds up so high that no matter what they do, no more power is made. What can happen when you over speed a turbine wheel you ask? Shrapnel not pretty. Also, Razor is correct, the hp gained won't be exactly matching as to the size shot you run when you get close to maxing out the capabilities of the turbo/turbine wheel. This is where and why back pressure readings are so important to know when you start dabbling with two power adders.
I would think that if you were running say a PT70/71 GTQ with an .85 A/R 3-bolt turbine housing and were wanting to run N2O with it, downpipe size and exhaust size would be the most critical aspect to have to deal with due to the discharge limitations on the .85 A/R housing. I would run a minimum 3.5" dp and minimum 3" dual exhaust with straight flow through mufflers and no internal bends or step downs if wanting to run larger than a 150 shot. The major long term concern to consider would be the added pressures that would be applied to your piston rings and the excess pressure that can build up in the crank case if you have any significant blow by. Some might not think N2O is that big a deal, but when you're dealing with 900-1000psi of N2O added with 30psi of 900cfm compressed air, things can get real tricky in a hurry. I wouldn't even think of trying to run boost plus nitrous on a stock ECM. The only way to successfully pull off running a serious combo and a large shot is with an aftermarket EMS system that has Wide Band O2 fuel correction factors and a custom N2O timing curve. (FAST & BS3) I witnessed a couple of guys back home take a stock turbos deep into the 11's with N2O and custom N2O chips, but it was only a matter of time before things came apart. Sure it flys now, but you will eventually pay when you play with N2O.
Sorry to ramble on, very good post btw.
Patrick
When you run N2O with boost, there is a chance of over speeding the turbine wheel due to the excess exhaust flow created with the N2O. This is another reason why it is so critical to run a larger than normal external wastegate mounted before the inlet of the turbine housing. In the Import world, especially the Supra guys, they typically run a large turbine housing A/R and either spray off the line to spool up, or spray the entire run to make more mph and keep the huge turbo spooled up between shifts. I know Boost Logics record setting Supra ran a GT4788 turbo with the largest housing available (1.08 A/R T5 style housing) and a 250 hp shot of N2O that was run during the entire run. This car also ran a best of a 7.86 @ 186 using this method. What I have seen in my years not only with PTE but friends experiences in the past, the turbo will always be the bottle neck, due to not only the turbine housing discharge area (how large of a discharge on turbine housing) but also what the turbine wheel can safely handle. If the turbo is rated to support say 900 fwhp, this would typically be at round the 30-32psi or at the point that back pressure would exceed the 2:1 ratio. With regards to back pressure, the general rule of thumb states, Whenever your back pressure exceeds the 2:1 ratio (Ex: 60 psi of back pressure measured just before the inlet of the turbine housing vs 30 psi of boost measured at the discharge of the compressor cover) the turbine wheel is either out of it's efficiency range, or the turbine housing is too small. I've seen huge gains in hp, sometimes over 100hp in full blown racing applications, by simply stepping up the size of the turbine housing. This is where some have gotten into trouble, either they run too much N2O & over speed the turbine wheel, or the back pressure builds up so high that no matter what they do, no more power is made. What can happen when you over speed a turbine wheel you ask? Shrapnel not pretty. Also, Razor is correct, the hp gained won't be exactly matching as to the size shot you run when you get close to maxing out the capabilities of the turbo/turbine wheel. This is where and why back pressure readings are so important to know when you start dabbling with two power adders.
I would think that if you were running say a PT70/71 GTQ with an .85 A/R 3-bolt turbine housing and were wanting to run N2O with it, downpipe size and exhaust size would be the most critical aspect to have to deal with due to the discharge limitations on the .85 A/R housing. I would run a minimum 3.5" dp and minimum 3" dual exhaust with straight flow through mufflers and no internal bends or step downs if wanting to run larger than a 150 shot. The major long term concern to consider would be the added pressures that would be applied to your piston rings and the excess pressure that can build up in the crank case if you have any significant blow by. Some might not think N2O is that big a deal, but when you're dealing with 900-1000psi of N2O added with 30psi of 900cfm compressed air, things can get real tricky in a hurry. I wouldn't even think of trying to run boost plus nitrous on a stock ECM. The only way to successfully pull off running a serious combo and a large shot is with an aftermarket EMS system that has Wide Band O2 fuel correction factors and a custom N2O timing curve. (FAST & BS3) I witnessed a couple of guys back home take a stock turbos deep into the 11's with N2O and custom N2O chips, but it was only a matter of time before things came apart. Sure it flys now, but you will eventually pay when you play with N2O.
Sorry to ramble on, very good post btw.
Patrick
Humm I was going to use a small shot of nitrous and add a alky kit to my grand national for next year, Use the nitrous just to spool the 9'' 3400 art carr off the line, Didn't know there was so much trouble, Would the alky and nitrous work ok together
With a small amount of N2O for spoooling there shouldn't be a big issue it looks like when you are spraying a lot of N2O all the way down the track that you start maxing out the exhaust housing flow and running into issues.
ks
BillyRValentine
Capricorn
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I was a nitrous junkie long before getting into turbo cars and as many others the Turbo Buick was my first foray into the turbo world. Several years ago I was spraying 50/75/100-shots on my previous Turbo-T. My current GN will use a 50-shot from the same plumbed up-pipe. At first I used it to help spool the turbo before the installation of the Vigilante. On the Dyno this is what I saw with a 50-hp wet shot (Turbo 487-RWHP/525-RWTQ then N20 545-RWHP/610-RWTQ). See the difference in the torque? That is where my car really began to shine. It was a little bit rich according to the dyno's O2 sensor so I leaned it out with the fuel jet and it responded with 562-RWHP/628-RWTQ. I also noticed that with the N2O it moved by peak down several hundred RPM. I ran it like this for several years. It worked so well that I sold my front mount and put on of Jack's stock location intercoolers in place. The car didn’t slow one bit and that is what has pushed me into my current thought process regarding N2O and stock location intercoolers. I never did dyno that combo but am currently building a very similar one for my current GN but with a little smaller turbo just to test a theory I have. I WILL be using one of Julio's alcohol kits as it too is part of my theory and I want to be able to compare my results. I will post my results and thought process after everything is said and done. I can tell you this with confidence - that little blue bottle makes a wonderful addition to a turbo car. I have found that the further away the nozzle (Within reason to soften up the hit.) the better it atomizes with the incoming air of the turbo. By doing so it helps to spread the oxygen molecules around within the incoming stream and seems to make a much better torque curve instead of being so linear. I found this route to be more usable for getting the power to the ground. Again these are just my findings and others may experience different results. Keep in mind that allot of people disapprove the use of N2O on turbo cars but I can tell you that the two absolutely love one another when used with a little common sense. On another note I found that when the shot begins to rise and "STOOPID" power can be made but the ignition had best be dead nuts on, but that is another story. Take care and I hope this helps.
Julio, the answer to your question from my findings is - yes N2O will raise the bar of the turbo in relation to how much HP/TQ it will make max. Even though it is being assisted it will still lay down the numbers all else being the same but I cannot stress the importance of the ignition system. I would LOVE to see a N2O/Alcohol kit somewhere in the near future. Having run alcohol on the fuel side of my N2O kits for years I can say it has always given me a piece of mind due to it's ability to keep pre/post detonation in check. If you need any additional info PM me for my number and I will gladly share with you my findings.
Jim C.
Julio, the answer to your question from my findings is - yes N2O will raise the bar of the turbo in relation to how much HP/TQ it will make max. Even though it is being assisted it will still lay down the numbers all else being the same but I cannot stress the importance of the ignition system. I would LOVE to see a N2O/Alcohol kit somewhere in the near future. Having run alcohol on the fuel side of my N2O kits for years I can say it has always given me a piece of mind due to it's ability to keep pre/post detonation in check. If you need any additional info PM me for my number and I will gladly share with you my findings.
Jim C.
