Should I get bigger injectors? - GT-R Register - Official Nissan Skyline and GTR Owners Club forum

Bajie · 27th October 2005, 01:34 PM

Hi All

After having "too much" work done on the car I am going the Power FC Pro route and having the car mapped properly in the not too distant future.

I have ...

R34 bottom end, modified for safety but still with standard piston size.
R34 turbo's. Standard.
HKS 264 cams.
HKS vernier pulleys.
Standard intercooler with hard pipe kit.
Airbox.

Now, I have never really been a dyno person. I know that the limiting factor for bigger hp on the car is the airbox and the intercooler [rated at 500sih from the factory]
Would the car benefit from putting 550cc injectors on when the car is mapped?

All help gratefully accepted.

Ian.

Cord · 27th October 2005, 01:40 PM

Nope not needed. And with a decent panel filter I definately wouldn't say the airbox is limiting you.

Pikey · 27th October 2005, 05:50 PM

Hmm, you're gonna be running over 400hp with that setup (?) so you're at 90% duty cycle at that point, which is ok. Any more than that is pushing it a bit.

Do you intend to go any further at any point in the future? And can you afford another £500 at this stage?

Bajie · 28th October 2005, 07:25 AM

Cord, cheers

Pikey: I was hoping you would comment as I've followed your ups and downs with the your car [on here].
I had a long think and discussion about what I was doing with the car next. I don't want to afford injectors at the moment, if it needed to be done I would have but really want the car on the road, driving and making me happy.
I'll leave it as is for now and have pencilled in intercooler, fuel pump and injectors in six to eight months time.

Thanks for the comments. They help. A lot.

GTR-Zilla · 28th October 2005, 10:58 AM

the general rule that injectors should not be run past 80-85% duty cyle, is the one I follow. People could shoot me down in flames, but if your duty cycle exceeds that amount buy some injectors.

Bajie, what ecu have you decided on?

Cord · 28th October 2005, 11:11 AM

With a Tomei/Nismo adjustable fuel reg you will be able to get late 400bhp from stock injectors without running silly duty cycle

skyline69_uk · 28th October 2005, 12:24 PM

I want to move to about 380whp next year and was told that I would need new injectors for this but I'm currently at 311whp and the injector run at ~78% if that helps any.

Eagle Eyes · 28th October 2005, 12:37 PM

Quote:

Originally Posted by Cord

With a Tomei/Nismo adjustable fuel reg you will be able to get late 400bhp from stock injectors without running silly duty cycle

How much increase in fuel pressure are we looking at?

Bajie · 28th October 2005, 01:07 PM

Quote:

Originally Posted by GTR-Zilla

Bajie, what ecu have you decided on?

I started wanting HKS-FConV then got excited by the AEM thread and was going to get one of those.
Then I drove the car to work and one of the blasted intercooler pipes came off [thought the engine had gone bang].
So, after a call to my mechanic he came down, spent £1.40 on some jubilee clips, put the hose back on and the car is ok. Except for the alloy that got scuffed when pulling to the kerb and losing all my power steering when she stalled

Anyway, changed my mind about the AEM and started looking at the Power FC. If I can get one, get it mapped and hide the hand controller I'll be happy[ish].

Car makes me feel like I'm dating the most beautiful looking woman in the world. Except on closer inspection she has sharp teeth, false boobs and a cavern the size of the grand canyon.

gtr mart · 28th October 2005, 02:02 PM

I thought the intercooler was ok upto 550 / 600 bhp. Might not need to spend on that area Bajie.

Fuggles · 28th October 2005, 05:32 PM

Too big injectors can be a problem, the addage "bigger is better" does not always apply. Make sure the injectors are mapped to your engine and adequate but not overprovisioned for your set up.

One of the Club members is writing an article about this for the GTROC Magazine, possibly December, or March 2006.

27th October 2005, 01:34 PM	#1 (permalink)
Bajie Banned Join Date: Dec 2001 Location: London Posts: 3,698	Should I get bigger injectors? Hi All After having "too much" work done on the car I am going the Power FC Pro route and having the car mapped properly in the not too distant future. I have ... R34 bottom end, modified for safety but still with standard piston size. R34 turbo's. Standard. HKS 264 cams. HKS vernier pulleys. Standard intercooler with hard pipe kit. Airbox. Now, I have never really been a dyno person. I know that the limiting factor for bigger hp on the car is the airbox and the intercooler [rated at 500sih from the factory] Would the car benefit from putting 550cc injectors on when the car is mapped? All help gratefully accepted. Ian. __________________ Kakimoto Exhaust for Sale tulibu dibu douchoo 360 spinner at Spa Jaffa survived a trackday with me MX5 VR limited Combination A RK500 with Serious Performance バジエアールケイ五百＝　セリウズ　パフォーマンス

28th October 2005, 07:25 AM	#4 (permalink)
Bajie Banned Join Date: Dec 2001 Location: London Posts: 3,698	Cord, cheers Pikey: I was hoping you would comment as I've followed your ups and downs with the your car [on here]. I had a long think and discussion about what I was doing with the car next. I don't want to afford injectors at the moment, if it needed to be done I would have but really want the car on the road, driving and making me happy. I'll leave it as is for now and have pencilled in intercooler, fuel pump and injectors in six to eight months time. Thanks for the comments. They help. A lot. __________________ Kakimoto Exhaust for Sale tulibu dibu douchoo 360 spinner at Spa Jaffa survived a trackday with me MX5 VR limited Combination A RK500 with Serious Performance バジエアールケイ五百＝　セリウズ　パフォーマンス

28th October 2005, 12:24 PM	#7 (permalink)
skyline69_uk GTROC Member Join Date: Jan 2005 Location: NI Posts: 2,833	I want to move to about 380whp next year and was told that I would need new injectors for this but I'm currently at 311whp and the injector run at ~78% if that helps any. __________________ Do it right or don't do it at all. "You're a pack of a**holes!" - Jim Richards 1992. スカイライン６９　UK

28th October 2005, 05:32 PM	#11 (permalink)
Fuggles GTROC Chairman Join Date: Jul 2001 Location: UK Posts: 16,936	Too big injectors can be a problem, the addage "bigger is better" does not always apply. Make sure the injectors are mapped to your engine and adequate but not overprovisioned for your set up. One of the Club members is writing an article about this for the GTROC Magazine, possibly December, or March 2006. __________________ . GTROC chairman Please feel free to contact me with any GTROC questions send an email to info@gtr.co.uk or send a PM

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27th October 2005, 01:40 PM	#2 (permalink)
Cord GTR Register Member Join Date: Aug 2002 Location: RB Motorsport Posts: 1,566	Nope not needed. And with a decent panel filter I definately wouldn't say the airbox is limiting you.

27th October 2005, 05:50 PM	#3 (permalink)
Pikey GTR Register Member Join Date: Feb 2004 Location: Cheltenham Posts: 4,151	Hmm, you're gonna be running over 400hp with that setup (?) so you're at 90% duty cycle at that point, which is ok. Any more than that is pushing it a bit. Do you intend to go any further at any point in the future? And can you afford another £500 at this stage?

28th October 2005, 10:58 AM	#5 (permalink)
GTR-Zilla Banned Join Date: May 2005 Location: London Posts: 2,099	the general rule that injectors should not be run past 80-85% duty cyle, is the one I follow. People could shoot me down in flames, but if your duty cycle exceeds that amount buy some injectors. Bajie, what ecu have you decided on?

28th October 2005, 11:11 AM	#6 (permalink)
Cord GTR Register Member Join Date: Aug 2002 Location: RB Motorsport Posts: 1,566	With a Tomei/Nismo adjustable fuel reg you will be able to get late 400bhp from stock injectors without running silly duty cycle

28th October 2005, 02:02 PM	#10 (permalink)
gtr mart GTR Register Member Join Date: Mar 2004 Posts: 1,637	I thought the intercooler was ok upto 550 / 600 bhp. Might not need to spend on that area Bajie.