rx7 engine rebuild set up for NOS
01-03-14, 12:12 AM
#1
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rx7 engine rebuild set up for NOS
Hi guys,
i just blew my seals on my FD and i thought to my self if im going to rebuild it again i might aswell make it strong enough for NOS. basically i want to know what else is needed so my engine can run NOS comfortably for just a squirt here and there and to purge it for show. bellow are my mods
v-mount
single turbo t04z
x4 1000cc top mount inj
alloy radiator
3" hi flow exhaust
midpipe
downpipe
microtech ecu + hand controller
exeedy heavy clutch + lightened flywheel
turbosmart e-boost boost controller
bosh 550 fuel pump
i just blew my seals on my FD and i thought to my self if im going to rebuild it again i might aswell make it strong enough for NOS. basically i want to know what else is needed so my engine can run NOS comfortably for just a squirt here and there and to purge it for show. bellow are my mods
v-mount
single turbo t04z
x4 1000cc top mount inj
alloy radiator
3" hi flow exhaust
midpipe
downpipe
microtech ecu + hand controller
exeedy heavy clutch + lightened flywheel
turbosmart e-boost boost controller
bosh 550 fuel pump
01-03-14, 09:42 AM
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Step 1, find a better tuner, if you toasted your current engine he isn't up to par
Step 2, just turn up boost
Step 3 stop watching F&F movies, rotaries like nos NA, turbo and nos on pump is a tricky combo
Step 3, if your doing things for "show" you should first add as much neon/ led under light as possible, then strobes, then a louder blow off valve, then as many stickers as possible, all way cheaper than a 500$ nitrous kit
Step 2, just turn up boost
Step 3 stop watching F&F movies, rotaries like nos NA, turbo and nos on pump is a tricky combo
Step 3, if your doing things for "show" you should first add as much neon/ led under light as possible, then strobes, then a louder blow off valve, then as many stickers as possible, all way cheaper than a 500$ nitrous kit
01-03-14, 03:34 PM
#8
The above comment regarding figuring out why your engine blew is spot-on. If you don't understand the root cause of your previous engine failing, adding a level of complexity and risk to your new setup can easily lead to another failure. Nitrous isn't anything to be afraid of in general, especially on simple naturally aspirated piston engines. Do some very careful research on how to control it. I'm not sure what Microtech you have, but you will want to control the nitrous with your ECU using RPM and TPS conditions.
I assume you'll be using a wet shot. You're going to have to experiment with different jetting combinations and start out small. The other thing you need to carefully consider is the effect of the nitrous on boost control and spark timing. The nice thing about nitrous is the very cold intake temps, which is good for knock relief. However, if your boost overshoots you could have big problems.
Here is what I suggest you implement from a controls perspective.
1) nitrous window functionality, so nitrous sprays from perhaps 2000-6000rpm, with TPS in the WOT range.
2) some kind of offset for spark control. You will need timing retard for additional safety margin. This will keep peak combustion pressure from getting too high. You could set it up so that nitrous operation will pull a fixed number of degrees from your timing, or switch to a new map altogether.
3) Bottle heater control, purge, and arming switch could all be manually controlled and not integrated into the ECU.
4) from a failsafe perspective--you at the very least need a carefully selected overboost fuel cut in the event that the wastegate is overwhelmed. It will be especially bad in colder ambient temps.
Again, I don't know what Microtech you have. Considering most (all?) can't even save the mapping to a separate file, I recommend you ditch it and go with something new (not a Power FC, not a 10 year old Haltech) that has flexibility in the outputs and software controls. If you didn't understand what I just wrote, and you're not willing to put in the time, money, and risk, then nitrous isn't for you. Nitrous + Turbo is not for the feint of heart.
As for apex seals and other internal changes... while they might be nice, if you had to focus on any one thing, it is proper controls. IF the spark timing is offset enough through your ECU during nitrous oepration, peak combustion pressure should stay low enough to keep from breaking something as long as severe knock can be prevented. Peak combustion pressure is very sensitive to spark timing.
I assume you'll be using a wet shot. You're going to have to experiment with different jetting combinations and start out small. The other thing you need to carefully consider is the effect of the nitrous on boost control and spark timing. The nice thing about nitrous is the very cold intake temps, which is good for knock relief. However, if your boost overshoots you could have big problems.
Here is what I suggest you implement from a controls perspective.
1) nitrous window functionality, so nitrous sprays from perhaps 2000-6000rpm, with TPS in the WOT range.
2) some kind of offset for spark control. You will need timing retard for additional safety margin. This will keep peak combustion pressure from getting too high. You could set it up so that nitrous operation will pull a fixed number of degrees from your timing, or switch to a new map altogether.
3) Bottle heater control, purge, and arming switch could all be manually controlled and not integrated into the ECU.
4) from a failsafe perspective--you at the very least need a carefully selected overboost fuel cut in the event that the wastegate is overwhelmed. It will be especially bad in colder ambient temps.
Again, I don't know what Microtech you have. Considering most (all?) can't even save the mapping to a separate file, I recommend you ditch it and go with something new (not a Power FC, not a 10 year old Haltech) that has flexibility in the outputs and software controls. If you didn't understand what I just wrote, and you're not willing to put in the time, money, and risk, then nitrous isn't for you. Nitrous + Turbo is not for the feint of heart.
As for apex seals and other internal changes... while they might be nice, if you had to focus on any one thing, it is proper controls. IF the spark timing is offset enough through your ECU during nitrous oepration, peak combustion pressure should stay low enough to keep from breaking something as long as severe knock can be prevented. Peak combustion pressure is very sensitive to spark timing.
