Injector opinions?

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Jan 18, 2008 | 01:20 AM

C5B

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Racer

Joined: Jan 2003

Posts: 411

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From: Newhall CA

Injector opinions?

Folks, as I plan my next upgrades, it's clear I am going to need new injectors. Does anyone have opinions on quality/reliability of injector brands?

Bosch
Lucas
FAST
Siemens

I'd like to get a matched set, but I keep striking out on 36# matched. 36# is all I expect to ever need. 30# might cut it, but I don't want my IDC to be pegged when I finally hit the numbers I want. So, 36# is it (maybe 32#).

Thanks!

- Colby

Jan 18, 2008 | 07:12 AM

see5

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From: Hobart, WI

I have had good luck with SVO36s. If you want to change intakes use the LS2s which are 33 or LS7 which are 40#.

Jan 18, 2008 | 07:19 AM

vettenuts

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Joined: Mar 1999

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From: At the beach in little Rhody

I am running the SVO 30# and they seem to work well and my tuner told me they are easy to tune. In my C4, I installed a set of RC Engineering (Lucas) injectors which are the disc injectors. They solved a lot of the problems typical in an L98 like hot start. They are expensive though.

Jan 21, 2008 | 06:44 PM

C5B

Thread Starter

Racer

Joined: Jan 2003

Posts: 411

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From: Newhall CA

How much whp would a 30# injector be good for? And still have a little room (that is, IDC in 80-85% range).

- Colby

Jan 21, 2008 | 06:53 PM

vettenuts

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From: At the beach in little Rhody

If you go to RC Engineering's web site, they have all the calculators to figure it out. I believe the SVO 30# rating is at a lower pressure (43 or 48 psi) so running them at 58 psi will result in higher flow. Hopefully someone can correct my numbers here, but bottom line is they will support quite a bit of N/A hp.

Jan 21, 2008 | 07:46 PM

see5

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From: Hobart, WI

~35# in a IFR table. Depends, but probably ~450 RW NA.

Jan 21, 2008 | 11:58 PM

C5B

Thread Starter

Racer

Joined: Jan 2003

Posts: 411

Likes: 1

From: Newhall CA

Thanks all! I didn't realize that the stock injector rating was rated at 58psi. I just couldn't understand why the 30# injectors were so popular

So, a 30# injector can support quite a bit more than the stock ones.

Thanks!

- Colby

Jan 25, 2008 | 01:53 PM

chevy406

Tech Contributor

Joined: Sep 2005

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From: New Market AL

I also have been researching injector sizing and selection. A recent data log on my car showed 98% duty cycle at the top of third gear. I found the following formulas on Accel's website:

fuel lbs/hr = (Max HP x BSFC)/(number of injectors x duty cycle)
*typical BSFC for NA engine is .45 to .55 and .55 to .65 for boosted engines

lbs/hr at operating fuel pressure = (square root of (new psi / advertised psi)] x advertised lb/hr

For example:

fuel injector size = (400 hp x 0.5) / (8 x 0.85) = 29.4 lbs/hr

actual flow rating = (square root of (58.5 psi / 43 psi)) x 30 lbs/hr = 35 lbs/hr

By re-arranging the equation you can calculate that 35 lb/hr injectors are good for 476 hp at 85% duty cycle. Remember that this is flywheel HP, and is using an assumed BSFC. But it does prove that the SVO 30# injectors should be good to around 450 rwhp (maybe pushing to around 90% DC at that level).

Anybody have a set of 30# SVO's for sale (also see my WTB in the classifieds)?