decreasing turbo spool rpm
04-25-05, 02:24 PM
#1
decreasing turbo spool rpm
Does anyone have any ideas on how to reduce the rpm at which the turbo spools up?
Do you think headers would help, what about using larger exhaust piping, anything else?
Or is the spool speed the spool speed and thats it?
Do you think headers would help, what about using larger exhaust piping, anything else?
Or is the spool speed the spool speed and thats it?
04-25-05, 02:31 PM
#2
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A larger exhaust will help a bit. You can always install an electric cutout to bypass your exhuast entirely so that you will have faster spool when you want it. It will be loud, but it will spool faster. I have a turbo honda and just simply opening the cutout reduces my spool time by a few hundred rpm. There is always the trusted small shot of nitrous to help spool faster. This is used widely buy the supra guys with their large turbos.
-Nick
-Nick
04-25-05, 04:16 PM
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Actually your wrong, larger tubing for the headers will make it spool slower as it slows down the air velocity.
SMALLER header piping CAN help spool the turbo faster.
What you may have to do is switch to a smaller A/R housing on the turbo.It can limit the HP up top but it will definately spool faster.
What are the specs of the turbo now and what RPM is it building boost?
SMALLER header piping CAN help spool the turbo faster.
What you may have to do is switch to a smaller A/R housing on the turbo.It can limit the HP up top but it will definately spool faster.
What are the specs of the turbo now and what RPM is it building boost?
04-25-05, 05:45 PM
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Originally Posted by morris
to4e t62-1 I believe it was .83ar
autotranny = crap
GT35r would solve this problem...... for $1400..lol
Bigger exhaust/cutout.. is your turbo ball bearing?
What rpm do you see 1psi? When do you hit full boost? What is full boost?
If full boost is 8 psi, you may hit 14 psi 100 rpm later.
04-25-05, 05:50 PM
#7
it comes on at 2800-2900 rpm and hits a full 8 psi by 3000-3100rpm, if I remeber correctly. It really isnt a problem, I just liked the way a SC always had the torque even from like 1000rpm on up.
yes it has the ball bearings but not the ceramic ones.
yes it has the ball bearings but not the ceramic ones.
Originally Posted by bags
autotranny = crap
GT35r would solve this problem...... for $1400..lol
Bigger exhaust/cutout.. is your turbo ball bearing?
What rpm do you see 1psi? When do you hit full boost? What is full boost?
If full boost is 8 psi, you may hit 14 psi 100 rpm later.
GT35r would solve this problem...... for $1400..lol
Bigger exhaust/cutout.. is your turbo ball bearing?
What rpm do you see 1psi? When do you hit full boost? What is full boost?
If full boost is 8 psi, you may hit 14 psi 100 rpm later.
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04-25-05, 06:06 PM
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I know people that would KILL for full boost by 3100 RPM!!!!!!!!!!!!!!!!!!!!
Even with the stock rev limiter that gives you over 3000RPM under full boost.Thats should make for a VERY uasable powerband.
Even with the stock rev limiter that gives you over 3000RPM under full boost.Thats should make for a VERY uasable powerband.
04-25-05, 07:50 PM
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Morris, I out ot kick you in the shin. I'll bet you a Ruth Chirs steak that you have MORE TQ throughout the entire rpm band now. Heck, I bet you your drink of choice that you have 100 ft lbs more @ 3300 rpm
Originally Posted by morris
it comes on at 2800-2900 rpm and hits a full 8 psi by 3000-3100rpm, if I remeber correctly. It really isnt a problem, I just liked the way a SC always had the torque even from like 1000rpm on up.
yes it has the ball bearings but not the ceramic ones.
yes it has the ball bearings but not the ceramic ones.
04-25-05, 08:21 PM
#10
The spool that you have now is not bad for that size turbo..granted it is on a V8.. On a 4 cyl with a 62-1 you are gonna be lucky to see spool by 4500rpm.
Fabricating actual exhaust manifolds with equal length primaries into a proper collector would still drop your spool even more. Also reducing the piping size would help a ton. Looks to be 2.5" on each bank coming off your stock mani's..is that right? I would also have wrapped the tubes (Thermo Tec) or ceramic coated them to keep the heat in.. hot air moves faster and that is what you want in this case.
Overall.. not a bad budget job, but alot of corners were cut.
Your current fuel system worries the heck outta me.
Maybe if the SAFC were boost mapped it would be good.. but right now it is running your fuel based on throttle open %.. and a turbo is non-linear in it's boost and fuel needs..unlike a supercharger.. Drive carefully.
Fabricating actual exhaust manifolds with equal length primaries into a proper collector would still drop your spool even more. Also reducing the piping size would help a ton. Looks to be 2.5" on each bank coming off your stock mani's..is that right? I would also have wrapped the tubes (Thermo Tec) or ceramic coated them to keep the heat in.. hot air moves faster and that is what you want in this case.
Overall.. not a bad budget job, but alot of corners were cut.
Your current fuel system worries the heck outta me.
Maybe if the SAFC were boost mapped it would be good.. but right now it is running your fuel based on throttle open %.. and a turbo is non-linear in it's boost and fuel needs..unlike a supercharger.. Drive carefully.
04-25-05, 08:36 PM
#11
Originally Posted by LMSguy
I know people that would KILL for full boost by 3100 RPM!!!!!!!!!!!!!!!!!!!!
Even with the stock rev limiter that gives you over 3000RPM under full boost.Thats should make for a VERY uasable powerband.
Even with the stock rev limiter that gives you over 3000RPM under full boost.Thats should make for a VERY uasable powerband.
Hehehe.. I just got in from road testing a car I just finished building a kit for..2000 Prelude..stock engine. t3t04e with stage3 wheel, 7psi, tubular manifold and intercooler and fuel system were all built here in-house. Starts making boost at 1800rpm and full 7psi by 2800rpm. Granted that is in 5th gear.
In 3rd just squeezing on the gas(about 40% throttle) I'm making boost starting at 2300rpm and full boost by 3200. Going to the dyno tomorrow looking to make about 280 fwhp.
04-26-05, 04:14 AM
#12
Bags, I'm not complaining I am very happy with the outcome. Everyone that has driven or ridden in it both with the Supercharger and with the turbo says it feels like it is much faster and making much more power now. Once it hits 3000 rpm it is almost like you have to hold on, in fact it is scary on curves, I try to already be in the boost on corners so that the rear doesnt suddenly break loose
I am new to turbos so I am real curious about the engineering aspects and how it all works, thats my primary reason for making the thread. I didnt know if the spool rpm was fixed or if it could be altered without altering the turbo.
The pipes I believe are 2" or 2.5" it is the same size as the manifold pipes, so you cant really make it smaller without shrinking it more than the manifolds which I believe would be a bad thing and they are now coated, that was one of the delays, getting it from the powdercoater. While it isnt a $25,000 SRT twin turbo setup, I dont know if I would say lots of corners were cut. For what I had as a budget it is a pretty darn good setup if I do say so myself and when you add on top of that the fact that it is all hand made, first prototype kit and that there are no existing setups to use as a template to follow, what more could you ask for.
Yes I guess you could use smaller turbos that would spool faster but then you loose out on the top end so there is always a level of compromise, there are tons of turbo combinations you could try it is only a matter of time and money.
I am expecting to replace the SAFC with a differetn Piggy back very soon, I am currently leaning heavily towards the Split second fuel timing computer. With the leaky rings I am sort of babying the throttle any how. I know Lextreme has had very good results with it and is well satisfied with split second.
I am new to turbos so I am real curious about the engineering aspects and how it all works, thats my primary reason for making the thread. I didnt know if the spool rpm was fixed or if it could be altered without altering the turbo.
The pipes I believe are 2" or 2.5" it is the same size as the manifold pipes, so you cant really make it smaller without shrinking it more than the manifolds which I believe would be a bad thing and they are now coated, that was one of the delays, getting it from the powdercoater. While it isnt a $25,000 SRT twin turbo setup, I dont know if I would say lots of corners were cut. For what I had as a budget it is a pretty darn good setup if I do say so myself and when you add on top of that the fact that it is all hand made, first prototype kit and that there are no existing setups to use as a template to follow, what more could you ask for.
Yes I guess you could use smaller turbos that would spool faster but then you loose out on the top end so there is always a level of compromise, there are tons of turbo combinations you could try it is only a matter of time and money.
I am expecting to replace the SAFC with a differetn Piggy back very soon, I am currently leaning heavily towards the Split second fuel timing computer. With the leaky rings I am sort of babying the throttle any how. I know Lextreme has had very good results with it and is well satisfied with split second.
04-26-05, 06:40 AM
#13
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Originally Posted by LMSguy
Actually your wrong, larger tubing for the headers will make it spool slower as it slows down the air velocity.
SMALLER header piping CAN help spool the turbo faster.
What you may have to do is switch to a smaller A/R housing on the turbo.It can limit the HP up top but it will definately spool faster.
What are the specs of the turbo now and what RPM is it building boost?
SMALLER header piping CAN help spool the turbo faster.
What you may have to do is switch to a smaller A/R housing on the turbo.It can limit the HP up top but it will definately spool faster.
What are the specs of the turbo now and what RPM is it building boost?
I guess I forgot to type that. opps.-Nick
04-26-05, 07:48 AM
#14
The 3" on the exhaust and V Band flanged downpipe is about as good as it gets. I was referring to the size of the piping used for the lower portion of the manifolds itself and the restrictive airflow of the stock upper manifolds.
No need to buy another fuel mgmt unit than the SAFC, just make it think differently. What does the rest of your fuel system consist of now? Upgraded pump? Larger injectors? The reason you could use the SAFC for your fuel mapping with the SC is b/c a supercharger is always the same boost and fuel needs at the same RPM..give or take a few %. That is why it was okay to use the SAFC which uses Throttle Open % (TH Point) to meter the fuel betwen the Lo/Hi throttle maps. A turbo is a much different animal.
I have had much success converting the SAFC to a boost sensing fuel mgmt computer and it would work for you as well. Your problem would be solved and you would be running safe (once dyno tuned) and could save that extra money for the rebuild. Retard your base ignition timing about 2* and you should be safe there as well..again a dyno will determine this for sure.
Happy boosting.
No need to buy another fuel mgmt unit than the SAFC, just make it think differently. What does the rest of your fuel system consist of now? Upgraded pump? Larger injectors? The reason you could use the SAFC for your fuel mapping with the SC is b/c a supercharger is always the same boost and fuel needs at the same RPM..give or take a few %. That is why it was okay to use the SAFC which uses Throttle Open % (TH Point) to meter the fuel betwen the Lo/Hi throttle maps. A turbo is a much different animal.
I have had much success converting the SAFC to a boost sensing fuel mgmt computer and it would work for you as well. Your problem would be solved and you would be running safe (once dyno tuned) and could save that extra money for the rebuild. Retard your base ignition timing about 2* and you should be safe there as well..again a dyno will determine this for sure.
Happy boosting.
04-26-05, 02:10 PM
#15
Stock fuel pump and 310 injectors, what do you have in mind for a fuel and timing management computer. I was thinking splitsecond but now I think it is only good for 1 atmosphere = 14.7 pounds. I would like to do 18 pounds if possible.
Originally Posted by Epik
The 3" on the exhaust and V Band flanged downpipe is about as good as it gets. I was referring to the size of the piping used for the lower portion of the manifolds itself and the restrictive airflow of the stock upper manifolds.
No need to buy another fuel mgmt unit than the SAFC, just make it think differently. What does the rest of your fuel system consist of now? Upgraded pump? Larger injectors? The reason you could use the SAFC for your fuel mapping with the SC is b/c a supercharger is always the same boost and fuel needs at the same RPM..give or take a few %. That is why it was okay to use the SAFC which uses Throttle Open % (TH Point) to meter the fuel betwen the Lo/Hi throttle maps. A turbo is a much different animal.
I have had much success converting the SAFC to a boost sensing fuel mgmt computer and it would work for you as well. Your problem would be solved and you would be running safe (once dyno tuned) and could save that extra money for the rebuild. Retard your base ignition timing about 2* and you should be safe there as well..again a dyno will determine this for sure.
Happy boosting.
No need to buy another fuel mgmt unit than the SAFC, just make it think differently. What does the rest of your fuel system consist of now? Upgraded pump? Larger injectors? The reason you could use the SAFC for your fuel mapping with the SC is b/c a supercharger is always the same boost and fuel needs at the same RPM..give or take a few %. That is why it was okay to use the SAFC which uses Throttle Open % (TH Point) to meter the fuel betwen the Lo/Hi throttle maps. A turbo is a much different animal.
I have had much success converting the SAFC to a boost sensing fuel mgmt computer and it would work for you as well. Your problem would be solved and you would be running safe (once dyno tuned) and could save that extra money for the rebuild. Retard your base ignition timing about 2* and you should be safe there as well..again a dyno will determine this for sure.
Happy boosting.