In the past year there's been a few hard core NA KA guys using bike throttle bodies to run indepentant throttle bodies on their motors. The advantage to running 4x40mm tb's to 1x60mm is obvious, but one can only wonder how much of a difference this would make on a boosted KA. The RB26 comes with ITB's stock. But in order to run them the runner lenth would be cut in half, would this take much away from the low end torque we all love so much? Or would the hp gains and throttle respose be worth it?
Redline
ITB's under boost...
Re: ITB's under boost... (Redline240)
I would think that ITBs would be better. I think that the low end torque that is lost (if noticable) would be worth the throttle response and high end gained.
-
AmoebAssassin
- Posts: 2424
- Joined: Wed Nov 17, 2004 7:11 am
- Car: 1991 Base fastback 5spd, black
Re: ITB's under boost... (mikerbike)
+1mikerbike wrote:I would think that ITBs would be better. I think that the low end torque that is lost (if noticable) would be worth the throttle response and high end gained.
As with any boosted application, flow is your friend. If you're really worried about losing low end, properly size your turbo so that your turbo spools low enough in the rev range to make up for losing low end NA punch.
This is precisely the setup i'm going for on my SOHC, using a garrett GT35/40R with GSXR 1000 43mm ITB's.
Although as most of the NA guys use rubber couplers to connect them to the lower manifold, i'm using flanges to eliminate any chance of leaks, expansion at the couplers due to boost etc.
The plenum design will also allow it to be disassembled to be cleaned or upgraded if necessary.
Although as most of the NA guys use rubber couplers to connect them to the lower manifold, i'm using flanges to eliminate any chance of leaks, expansion at the couplers due to boost etc.
The plenum design will also allow it to be disassembled to be cleaned or upgraded if necessary.
-
Checkered-Member
- Posts: 1593
- Joined: Wed Sep 24, 2003 7:14 am
- Car: 1998 Nissan Altima (modded)
2003 Audi A6 2.7T (stock) - Contact:
One restrictive plate >>> 4 restrictive plates
ITB is not the holly grail of engine mods, your engine can only take in so much air, 4x40mm TB or 4x100mm it's still going to flow the same amount, more then one TB, but if you want more flow, extrude hone the intake mani, port the head and add high duration cams...same result and you get to keep your low-end TQ
TQ >>> HP
Why make your car drive like a Honda?
In my opinion ITB is a waste on a boosted car, ITB's will only flow a little more because there are other flow restrictions
ITB is not the holly grail of engine mods, your engine can only take in so much air, 4x40mm TB or 4x100mm it's still going to flow the same amount, more then one TB, but if you want more flow, extrude hone the intake mani, port the head and add high duration cams...same result and you get to keep your low-end TQ
TQ >>> HP
Why make your car drive like a Honda?
In my opinion ITB is a waste on a boosted car, ITB's will only flow a little more because there are other flow restrictions
Re: (Checkered-Member)
Even if the engine can't suck in much more air/fuel, ITBs make the air more readily available. That is why there is a better throttle response. I would assume that they would be better suited to N/A applications though, because the air is already pressurized on a turbocharged engine. Oh well, try it and let us know.Checkered-Member wrote:One restrictive plate >>> 4 restrictive plates
ITB is not the holly grail of engine mods, your engine can only take in so much air, 4x40mm TB or 4x100mm it's still going to flow the same amount, more then one TB, but if you want more flow, extrude hone the intake mani, port the head and add high duration cams...same result and you get to keep your low-end TQ
TQ >>> HP
Why make your car drive like a Honda?
In my opinion ITB is a waste on a boosted car, ITB's will only flow a little more because there are other flow restrictions
-
Checkered-Member
- Posts: 1593
- Joined: Wed Sep 24, 2003 7:14 am
- Car: 1998 Nissan Altima (modded)
2003 Audi A6 2.7T (stock) - Contact:
Re: (mikerbike)
Better response...yes...but on a turbo application it will still be lagymikerbike wrote:
Even if the engine can't suck in much more air/fuel, ITBs make the air more readily available. That is why there is a better throttle response. I would assume that they would be better suited to N/A applications though, because the air is already pressurized on a turbocharged engine. Oh well, try it and let us know.
Re: (Checkered-Member)
Checkered-Member wrote:Better response...yes...but on a turbo application it will still be lagy
No it won't...ever heard of a little nissan motor called the RB26DETT?
4 throttle plates = higher intake velocity = higher VE = more TQ.
In a similar concept as the MAF, with ITB's each cylinder is getting near identical airflow.
You'll only lose low end torque if you go too short on the runners and/or don't tune the ecu to suit the itb's properly.In most cases ITB's will make the most difference in mid range torque, which reflects what i said about obtaining higher VE from higher intake velocity.
-
nissanfanatic
- Posts: 1314
- Joined: Mon Nov 01, 2004 8:41 pm
- Car: 1992 Nissan 240sx SE
- Contact:
Same concept as tubular exhaust manifolds Vs log manifolds.
Key here would be tuning the runners for where you want to make power. Or actually for where your cams make best power. If you can tune the intake runners spot on with where your cams make peak power and supply the necessary fuel, you'll have a golden setup. Even NA, it would scoot.
Key here would be tuning the runners for where you want to make power. Or actually for where your cams make best power. If you can tune the intake runners spot on with where your cams make peak power and supply the necessary fuel, you'll have a golden setup. Even NA, it would scoot.
-
WDRacing
- Moderator
- Posts: 15983
- Joined: Mon Nov 25, 2002 2:00 am
- Car: 95 240SX, 99 BMW 540i, 01 Chevy Express, 14 Ford Escape
- Location: MFFO
- Contact:
ITB's rock, to argue is gay...
In the end, its all about flow and intake air velocity...period. No one is going to fab a new intake manifold without modding most everything else first.
A new intake manifold will let the KA rev higher, sine the stocker is a very restrictive. Matched with a ported head, cams a good ex-mani and turbo combo you'll have a recipe for success.
It's simple really, and has already been said, but allow me to reitterate. What is the BESt engine Nissan has ever produced? What is the BEST IMO, but atleast in the top 5 best engines made period.
THE RB26DETT
In the end, its all about flow and intake air velocity...period. No one is going to fab a new intake manifold without modding most everything else first.
A new intake manifold will let the KA rev higher, sine the stocker is a very restrictive. Matched with a ported head, cams a good ex-mani and turbo combo you'll have a recipe for success.
It's simple really, and has already been said, but allow me to reitterate. What is the BESt engine Nissan has ever produced? What is the BEST IMO, but atleast in the top 5 best engines made period.
THE RB26DETT
Re: (WDRacing)
ITB's are great and all... But you notice how many BR26's install the veilside 110mm single TB? They all seem to do this for the high end power, even though ITB's are more responsive.
We should feel lucky thats one less thing to mess with for high power.
We should feel lucky thats one less thing to mess with for high power.
Re: (Red-KAT)
They are usually dyno queens/drag cars that do this.Red-KAT wrote:ITB's are great and all... But you notice how many BR26's install the veilside 110mm single TB? They all seem to do this for the high end power, even though ITB's are more responsive.
We should feel lucky thats one less thing to mess with for high power.