fd 93 dd
bnr stage 3 sequentials
power fc
full exhaust
meth

im sure responsiveness is mostly an NA subject but ide like to decrease turbo lag as much as possible as well.

so what are some good mods that give you a snappy powerband a sequential setup?

 

It doesnt get much more "snappy" than a sequential setup You could rebuild the engine with higher compression rotors but thats really about it.

 

can you dictate what issues you are having with response? what problems are you having because like was stated .. sequential system is kind of made for this kinda things , I can maybe walk you through some tricks to get better response but can you give me more details on your issue , what power you're running , was the car tuned?

 

If you are having a problem with lag on a sequential setup then it is probably the control system, may want to think about upgrading that.

 

One biggie is swapping out the rear gear in the diff. I went from the stock 4.10's to 4.44's from an RX-8. Really improves response and makes the car more "eager". You can get used RX-8 diffs cheap, but you do have to swap the ring and pinion. Search on my user name, I have a substantial writeup on this mod.

Dale

 

what RPM does your primary turbo reach target boost ? how's the transition ?

 

i dont have a problem with the lag i was just looking for ideas. changing the final gear is a good one what about pulleys?

 

there are things that could increase responsiveness without changing a single part .

but I need to know certain things to help you out .

 

i haven't driven the car with the bnr twins on it yet i guess that would help. im at stock boost until i get fuel so it should be about the same as stock twins but ill have them at 15psi soon.

 

Your tune when you get the extra fuel will be a big thing . I'd watch your AFRs and take it very easy on the car . as you may be overboosting .

 

If you have no heard of my Custom Solenoids. Maybe you can check out my GB link.

The custom solenoid system I provide "almost" eliminated the transition "dip". It is also heavy duty good with boost pressure up to 100PSI.

I currently have 2 extra sets available for purchase. These baby will make your BNR more lively ;-).

-AzEKnightz

 

what would cause overboosting? can i spot it with a boost gauge?

what about porting in regards to power agility or increasing the redline.

obviously i don't much about the subject. when i search i get topics about small turbos.

 

that's deffinatly going on my list. i love the sequentials but that dip could be potentially dangerous and not it's very track friendly.

 

i thought this thing spell checked. how could it do this to me

 

If the sequential system is working properly in stock form, the transition shouldn't be that noticeable. There can be issues with the control system which can create lag. However, the more boost you attempt to push, the more ineffective the stock sequential system becomes.

A few things that can help responsiveness (now whether you do them or not is up to you as there are typically some trade-offs):

* Add some backpressure (using like a racing based catalytic converter).
* Using an effective blow-off valve. One that will react quickly will increase responsiveness.
* Rear gear in the diff as mentioned by Dale.

There are always trade-offs so you need to determine which ones make sense for your use of the vehicle.

 

a tired engine will also create lag, perhaps a compression test to see where it is at may shed some light on poor performance which will never increase much if so.

 

hah , well I'd say start with the fuel . you dont want to have a blown engine because of lack of fuel .

yes you can tell if you overboost by the boost gauge , if your boost goes over 10 PSI , then you are over boosting , but more importantly your wideband gauge . because 10 psi on the BNR's may be much more , then 10 PSI on the stock twins . the ECU will think it needs this ammount of fuel but it needs more . and you may be going lean .

You need both a wideband , and a boost gauge to compare . your afr's at certain PSI's

 

My list for engine/turbo response-

Low restriction exhaust with as large as possible downpipe- twin tube design works well on FD.

Low restriction intakes to turbos with cool air available (as opposed to radiator waste or engine bay air).

lightweight flywheel.

Avoiding engine bay/intercooler heat soak with vented hood or isolating components.

Rear end gear (haven't experienced this, but it will always provide acceleration).

Light wheels/tires.

Modifying your sequential turbo system for full boost on primary turbo if running more than stock 10psi.

 

Lightweight flywheel, minimize IC piping length (what IC do you have?), as mentioned light wheels/tires but also an overall diameter not larger than the stock 25ish inch..... oh, and some white lithium grease on the business end of your throttle cable linkage

 

i've got a stock IC. i'm going to go for a 3 inch stock mount with the shortest pipes possible.

you bring up a good point with the throttle cable. maybe i should start another topic (or i could research...) about it but... what about car control responsiveness like steering and throttle. like a short shifter would be a good example.

i'de rather spend money on the driving experience and quality than hp and looks. at least for now.

 

I do not think increaseing the piping width will give you any improvement as it will still bottleneck at the Y pipe , and the intercooler itself .

but I'm not well versed in thermal expansion soo I wont give you a definittive answer .

and yes I agree asoon as the care is safe to abuse.. DO IT! thats kind of my thing

 

3" core IC, 2.50" pipes.

some one said a little exhaust restriction is good and one said to go for a free flowing exhaust.

which is it? but why?

 

Back pressure is good , because it keeps you from overboosting . IE a cat . will keep the car from boosting to 15 psi when it should be at 10 .

, free flowing you will get more power , and response , But risk the wastegate not being enough and boost creeping / spiking

you give up a little pwoer and response for safety

The stock IC Core / pipping are all 2.75 inches.

 

its the balance of free flow and exhaust velocity. Everything you do for an engine's powerband is a give and take.

The bigger the ports, the better your high rpm powerband will be at the expense of the low rpm range.

the smaller the intercooler, the faster the boost will build due to filling less volume, but the sacrifice will be in overall cooling ability at higher flow rates.

its all a give and take. what type of powerband you want. where you want that powerband, and how good is your tuning.

the sheer number of variables involved in answering this question is pretty astronomical.

 

some one said a little exhaust restriction is good and one said to go for a free flowing exhaust.

Backpressure is never going to be good except as noted above in reducing boost creep- in which case, the further from the turbo the better the spool will be for the same restriction in total flow.

Velocity can be a good thing to increase response and low end power.

In the case of the stock sequential system, I believe post turbine velocity won't be a factor as the tiny primary turbo turbine smooths all the exhaust pulses even at low low rpm and there is a constant velocity flow downstream of it. A smooth expansion to large diameter downpipe increases the pressure delta at the turbine to help spool (ie turbo response).

In the case of a really large single or parallel twins there may be some advantage to having a smaller diameter downpipe as the larger turbine sections will not completely damp the pulsations in velocity at low rpm and the engine has to push the exhaust out as the pulsations stack up and slow the overall exhaust velocity in the downpipe (ie naturally aspirated exhaust tuning theory).

I have only seen dyno evidence of a drop in low end power with big exhaust on 4cyl engines with big turbos. The general theory of turbo exhaust tuning theory is bigger is better.