Landracing Forum
Tech Information => Technical Discussion => Topic started by: Sumner on July 27, 2008, 12:13:34 PM
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So I don't screw up Mike's other thread I thought I would post this here:
Turbos and nitro! Can I watch!!!! :-o
The poor guy that wrote the story had a hard time some of which is just plan messed up, turbo with nitro I dont think so tim. maybe a little alky
Ok I'm curious and will ask the dumb question.
Why can't you use the two together?
I tried to google this without much success, but really only found this article on a 4 cylinder that is or is going to run that combination...
http://www.turbomagazine.com/tech/0202tur_norwoods_racing_funnycar_integra/index.html
..... while trying to find out if the car actually has run and what the results were I found that the builder Bob Norwood is no stranger to the salt......
http://www.bobnorwood.com/Norwood%20Story.htm
.............. was that his Ferrari that was totaled at Speed Week a couple years ago running a BBC?
Well back to the turbo/nitro thing since you can run a roots blower with nitro obviously and compressed air would seem to be compressed air I would think the turbo would work on the compressor side. So then I thought maybe the problem is on the turbine/exhaust side, but according to that article if it is right the EGT's are lower with nitro than gas even though we see all those flames coming out of the exhaust on nitro cars. He said that is because it burns slow and is still burning when the exhaust valve is opening.
So I guess I'm would like to still know why the two won't mix.
Thanks,
Sum
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You certainly can run turbochargers with nitro. In the early 80's Gale Banks, Jerry Verheul, & George Sitko ran a fuel dragster with turbos. Lot of teething problems like any untried project. Like any other development program it took tons of $$$$. NHRA also banned turbochargers from the fuel classes soon after this program was shut down.
Chase Knight also ran a twin turbo & blwon alky dragster for years on the east coast.
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Mike,
I was at LA County one day when Gale and the boys brought the car out. They were definitely having some teething problems. Like you say once you get off the beaten path and try new things it can be very expensive.
Tom G.
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I'd think it would be *extremely* challenging to be able to tune a nitro/turbo combo with only mechanical fuel injection. To do it on EFI would take fuel injectors too large to imagine (I'm guessing there's an industrial application somewhere but...)
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The fuel curve is the problem. @ 20-30% I would think it would`nt be to hard, but if you get greedy, and you will, backing the engine down after a run could be a problem. A roots or screw blower will usually be consistent with the boost. However in my experiance, the turbo is a little harder to spool up the same way every time. Im I wrong Mike? :mrgreen:
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No you're right John. It all depends on load, we can load the engine the same almost every time on the dyno but at the drag strip or the lake bed it's a lot tougher.
You can still back the engine down using the belt driven starter drive just like a blown car.
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Mike,
What is a belt driven starter drive and what is it used for?
Thanks in advance and thanks for all of the information you have shared with us on this forum.
Harvey
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Hi Harvey,
In applications where a crank or flywheel mounted starter won't fit for chassis or other reasons shops like RCD have a system where they mount a blower pulley on the crank and another in front of the timing cover with a bracket that mounts a starter drive like on a blower but without the blower. The belt connects the upper pulley with the lower pulley so you can install a 36 volt starter to rotate the motor. This same pulley will allow you to back down the engine afterwords.
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Thanks Mike,
I see what the pulleys and belts are used for now. I still can't understand what " back down the engine" means. Is it to turn the engine over by hand?
Don't want to miss anything that may help get an extra MPH.
Harvey
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No hp or mph in backing down the engine Harvey. It's a term used by fuel or Nitro racers. It means to turn the engine over backwards by hand after you shut it down from warm up. If you try to start the engine and it still has fluid in the chamber it can go off and do severe damage to the engine or even people. I'll let promachine tell you a story or 3..........
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Also not a bad idea before start up of any liquid cooled engine that might have suspected internal seepage problems. Helps in preventing short rods, cracked pistons, or other damage resulting from hydraulicking a cylinder.
Ed Purinton
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...........I'll let promachine tell you a story or 3........
Yes he told me when I was there. I didn't see the evidence, but was convinced none the same that it wasn't a pretty picture.
We made the mistake our second year about not pulling the plugs and turning the motor over and hydraulicked it in the morning after it had set all night with a bad seal on the blower that we didn't know about and the blower oil leaked down. We were done with the bad seal and didn't hurt the motor, but could have.
Learn from others mistakes,
Sum
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Well, the way I see it, when you back the engine down, you will push some of the remaining fuel in the cyl. out into the ex. I don`t think I would want the fuel pushing into the turbo housing. Maybe I am a little gun shy.
Remember Mike, you have to break a few eggs to make an omlett. :-o
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When Precision Auto was talking to Fast Electronics about which system to use on the 222 car they mentioned a car using nitro and one of ther systems making 4500 hp. I assumed it was turbocharged.
JL222
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I tryed to feed a 698" blown alky chevy with a Fast system once and ended up going back to mech. inj.. 16 nozzles, 4 pumps and 4 days on the dyno.
I don`t think they make nozzles big enough or pumps for that matter. It took a room full of batterys just to keep the pumps running. And we had to separate the dfi from everthing else that was 12 volt.
Nitro would take alote more, I just don`t think its possible. I could be wrong, anybody seen it done?
sign, Boom Boom.
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When Precision Auto was talking to Fast Electronics about which system to use on the 222 car they mentioned a car using nitro and one of ther systems making 4500 hp. I assumed it was turbocharged.
JL222
I assumed wrong its a roots type blower. The guys at Precision Auto thought thought nitro would be real hard on turbine wheels as the nitro burns so far and hot in the exhaust.
JL222
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I tryed to feed a 698" blown alky chevy with a Fast system once and ended up going back to mech. inj.. 16 nozzles, 4 pumps and 4 days on the dyno.
I don`t think they make nozzles big enough or pumps for that matter. It took a room full of batterys just to keep the pumps running. And we had to separate the dfi from everthing else that was 12 volt.
Nitro would take alote more, I just don`t think its possible. I could be wrong, anybody seen it done?
sign, Boom Boom.
We will be using a waterman cam driven fuel pump to get around the electrical drain (on our new Fast system) as we don't have an alternator, just 2 batteries.
JL222
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That seems to be the ticket. Good luck!
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I tryed to feed a 698" blown alky chevy with a Fast system once and ended up going back to mech. inj.. 16 nozzles, 4 pumps and 4 days on the dyno.
I don`t think they make nozzles big enough or pumps for that matter. It took a room full of batterys just to keep the pumps running. And we had to separate the dfi from everthing else that was 12 volt.
Nitro would take alote more, I just don`t think its possible. I could be wrong, anybody seen it done?
sign, Boom Boom.
We will be using a waterman cam driven fuel pump to get around the electrical drain (on our new Fast system) as we don't have an alternator, just 2 batteries.
JL222
Another trick to avoid power coupled noise, is to run a decent sized capacitor for the FAST. Does a nice job of smoothing out the rpm spikes caused by other electrical noise on the shared power source.
-scott
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If you need a capacitor there is something else wrong. Generally poor grounding either Battery negative as in ground loops poor connections or wire size. You can also have poor grounding inside the ecu. Any system that uses battery - as a sensor return wire would be suspect. Well designed systems have an internal ground plane isolated from battery- for sensor returns(ground sort of). You might also check the altenator as bad diodes will cause all sorts of problems most suspect or me are single wire import ones.
I had a fast system I was called to fix that was firing the ignition with key on engine off and not just one you could hear the coil buzzing away pretty shakey setup in my mind.
Dave
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JL, will the cam driven fuel pump have enough pressure while cranking to fire the injecters?
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JL, will the cam driven fuel pump have enough pressure while cranking to fire the injecters?
That was one of my concerns along with primeing because pump is above gas,but they say no problem. Will find out soon, i hope, no parts yet, today or tommorrow . If a problem we'll tap in our existing electric fuel pump that we use to prime with to pressurise the system.
JL222