decreasing turbo lag

G

garry goodall

Member +
how do you decrease spool time on your turbo, full boost comes in about 3,500 rpm on a ct9.

other mods: hks actuator at 0.7bar, uprated air filter, blitz nur spec, magnacore ht leads, fmic.

thanks in advance.
 
kellygt

kellygt

Member +
garry goodall said:
how do you decrease spool time on your turbo, full boost comes in about 3,500 rpm on a ct9.

other mods: hks actuator at 0.7bar, uprated air filter, blitz nur spec, magnacore ht leads, fmic.

thanks in advance.
Click to expand...

Aftermarket manifold and decat and shorten the hot pipe that should decrease your turbo spool time significantly or you could buy an electronic boost controller and get it set up by a tuner to bring the boost in faster and stronger
 
corofin12345

corofin12345

Member +
garry goodall said:
how do you decrease spool time on your turbo, full boost comes in about 3,500 rpm on a ct9.

other mods: hks actuator at 0.7bar, uprated air filter, blitz nur spec, magnacore ht leads, fmic.

thanks in advance.
Click to expand...

uprated manifold..decat and a bigger filter. or a ct9b

"edited"
 
Last edited:
Guye

Guye

Lifer
Copied from an old post I made in a similar thread:

Two main factors affect spool up...
1. The turbo's characteristics in relation to the engine it's paired to.
2. Wastegate control methods used.

No 1 is pretty straight forward. For example if you were to take the little ct9 and put it on a 2000cc high compression motor, it will spool like a supercharger because of the shear volume of exhaust gases the larger motor produces. Take a td05 and put it on a low compression 1000cc motor and well...you get the idea. Once the housing somehow increases or optimizes the exhaust gas flow around the turbine, the response will incease.

No 2 is a bit more complicated but is probably being used in this case. As you know the wastegate controls boost by diverting some of the exhaust gases away from the turbine, slowing it down to a stable rotation/boost level. Changing you stock actuator with a uprated unit will help keep the wastegate closed more efficiently, increasing spool up response slightly. Also, with the stock solenoid controlling it wastegate begins to open very early in the spool up cycle, hampering the overall response of the turbo (lets say you start seeing boost @ 2500rpm using this unit). Most bleed valves and mbc, while being used to increase the overall boost levels, also have the added advantage of keeping the wastegate closed fractionally longer than the stock solenoid. With the extra gases acting on the turbine for a longer period, you will notice that you spool up is quicker, and peak boost is seen at a lower rpm. The limitation is that with manual units, the wastegate, while opening later, still opens progressively, so the maximum response physically possible for the turbo cannot be acheived.
This last bit has been debated on this site before: IMO, the ultimate way to increase your spool up response is by using a ebc with the appropriate gain setting adjustments. While these are far more expensive and complicated than other wastegate control units (this is what all actuators, springs & boost controllers are anyhow) they allow the user who is willing to invest the time in tweeking the settings to get the maximum response from the turbo. E.g. with a good ebc you can set it so that the wastegate is forced to stay shut right up to the milisecond where the desire boost is reached (even if that level is stock boost) the open to slow the turbine, stabilizing the boost. If set correctly, it will seem as if your boost "spikes" and holds at the set level until redline. That spike is actually the massive response you gain with such settings. Hope this helps.

edit: just thought I would cover all factors relating to "what effects spool up" while I was at it...sorry for the essay.
__________________
 
G

gedis

Member +
Guye said:
Copied from an old post I made in a similar thread:

Two main factors affect spool up...
1. The turbo's characteristics in relation to the engine it's paired to.
2. Wastegate control methods used.

No 1 is pretty straight forward. For example if you were to take the little ct9 and put it on a 2000cc high compression motor, it will spool like a supercharger because of the shear volume of exhaust gases the larger motor produces. Take a td05 and put it on a low compression 1000cc motor and well...you get the idea. Once the housing somehow increases or optimizes the exhaust gas flow around the turbine, the response will incease.

No 2 is a bit more complicated but is probably being used in this case. As you know the wastegate controls boost by diverting some of the exhaust gases away from the turbine, slowing it down to a stable rotation/boost level. Changing you stock actuator with a uprated unit will help keep the wastegate closed more efficiently, increasing spool up response slightly. Also, with the stock solenoid controlling it wastegate begins to open very early in the spool up cycle, hampering the overall response of the turbo (lets say you start seeing boost @ 2500rpm using this unit). Most bleed valves and mbc, while being used to increase the overall boost levels, also have the added advantage of keeping the wastegate closed fractionally longer than the stock solenoid. With the extra gases acting on the turbine for a longer period, you will notice that you spool up is quicker, and peak boost is seen at a lower rpm. The limitation is that with manual units, the wastegate, while opening later, still opens progressively, so the maximum response physically possible for the turbo cannot be acheived.
This last bit has been debated on this site before: IMO, the ultimate way to increase your spool up response is by using a ebc with the appropriate gain setting adjustments. While these are far more expensive and complicated than other wastegate control units (this is what all actuators, springs & boost controllers are anyhow) they allow the user who is willing to invest the time in tweeking the settings to get the maximum response from the turbo. E.g. with a good ebc you can set it so that the wastegate is forced to stay shut right up to the milisecond where the desire boost is reached (even if that level is stock boost) the open to slow the turbine, stabilizing the boost. If set correctly, it will seem as if your boost "spikes" and holds at the set level until redline. That spike is actually the massive response you gain with such settings. Hope this helps.

edit: just thought I would cover all factors relating to "what effects spool up" while I was at it...sorry for the essay.
__________________
Click to expand...

good info lad, any advice on external wastegate setup with ebc?
 
corofin12345

corofin12345

Member +
kellygt said:
A bigger turbo would increase lag, removing the air-con and relocating the filter to the front would decrease spool up time
Click to expand...

what the fook was i saying.. i ment 2 say bigger filter.. dont know why i said that...:homer: fooking mnc is rotting my brain:haha:
 
Last edited:
Guye

Guye

Lifer
gedis said:
good info lad, any advice on external wastegate setup with ebc?
Click to expand...
Decide what you will run as a low boost level (10psi for e.g) and install the correct spring to set the external wastegate to that pressure. On the ebc, your low boost setting will be 0% since you will not be able to go lower than what your wastegate spring is set to. Depending on the features of you ebc, you will the use the set boost, start boost and gain settings to select and fine tune not only your peak boost levels, but also lower the rpm at which spool up begins and the overall time it takes from spool up to peak boost. If it is tuned for max response, the power delivery will be violent and sudden, almost like a controlled boost spike. If tuned for a progressive/linear spool up, the feel will not be as exciting as the violent low rpm surge you will get from max response, but the car will be more drivable with an easier to use/control power delivery. Make sure to set the boost limiter (a feature offered on many ebc) to below the ultimate boost your setup will support. In case of any spike or creep, the unit will default to a lower boost level of your choosing automatically while displaying a warning to protect against unintentional over boosting.
 
Fatman

Fatman

Member +
Some great info posted so far. I'm sure I posted extensively in a similar thread a while back.

Other than added spool from an electronically controlled external wastegate, any further significant gains are going to come from improving the efficiency of combustion and minimising or making the best compromise on other factors such as total intercooler pipe/core volume, reducing detrimental exhaust backpressure, simplifying piping route etc

The most successful way to significantly increase the responsiveness of the turbo package is to increase engine capacity. A 5e/ct9 setup is a joy to drive, the response is addictive.

Secondly is to increase engine static compression. Higher compression means more efficient combustion, increased exhaust velocity, earlier spool. A high compression (e.g 9.8:1 rather than the 4efte standard 8.5:1) also makes a very noticeable difference to the turbo response.

A good friend of mine, finx from these forums runs a ct9b on a standard internals 5e-fhe at 9.8:1 cr. I've seen 5-6psi at just over 1200rpm in 4th gear under load, it's quite amazing! Additionally he runs very short intercooler piping (2 inch) through a relatively small vr4 sourced intercooler. Tuned correctly (and with realistic expectations about how much power you're going to get) a setup along these lines is an ideal street driven power package, delivered torque when you need it without lag in virtually any gear.
 
glanza_dan

glanza_dan

Fresh Recruit
Defo somethink going rong there you be geting full boost by 2800-3,000 RPM
on the ct9.








garry goodall said:
how do you decrease spool time on your turbo, full boost comes in about 3,500 rpm on a ct9.

other mods: hks actuator at 0.7bar, uprated air filter, blitz nur spec, magnacore ht leads, fmic.

thanks in advance.
Click to expand...
 
finx

finx

Member +
three letters NOS


but on a more serious note...

i havnt read all the posts as its late but from my experience,i have see stock ct9s kicking in around 2500-3500rpm. depends allot on internal engine condition as much as whats bolted to the outside of it.

front mount with correct sized piping and core will gain spool up. trying to keep the piping one size the whole way and no larger than your T/B size also helps a great deal.
the correct sized aftermarket down pipe makes a huge difference to spool up (the rest of the exhaust system also needs to be upto scratch obviously)

aftermarket headers dont really increase spool up, some may tell you otherwise but from personal experience it didnt make a difference on my car or on numerous other turbo vehicles i have done work and moddifications and fabrication jobs on.

many more things that influnence turbo spool characteristics but allot has already been covered by the knowledgeable lads who have posted in this topic



cheers
Ryan
 
Franza1

Franza1

Supermoderator & Area Reps Manager
Like Bob said above by far the best and most effective way to decrease lag is an electronic boost controler, just to give you an idea.

i'm running 15 on the gain on my Blitz SBC, ported and polished head, heat wrapped Japspeed exhaust, filter re-located to front, heat wrapped Zisco de-cat and heat wrapped Toytuning mild steel manifold and i am getting full boost ( 1 bar ) at just about 2k and starts to boost at about 1.2-1.5k
 
Franza1

Franza1

Supermoderator & Area Reps Manager
Personally i'd stay away from the HDI ones, the solenoid has been known to fail. I'd go for a Blitz SBC they are very very easy to use and mine hasn't missed a beat since being in the car. nice beefy Solenoid on it too and around the same price from the states.
 
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