DI Write Up (good info...)

[Redline MS]

This just hit the web the last couple days...wrote it a few months back but after reading it again maybe some of the newbies might be able to take something out of it.....this is what 13 hours on a plane to UAE will make you do!! LOL

http://www.superchevy.com/how-to/eng...n-the-gen-v-8/

If you want to go back further this one we did over a year ago as an ice breaker...

http://www.superchevy.com/how-to/eng...-get-familiar/

HT

[Higgs Boson]

nice article Howard!!

[Ben Charles]

Good read... interesting info on the traditional pistons used on the Camaro build

[Redline MS]

Good read... interesting info on the traditional pistons used on the Camaro build

For sure...we had been working with Wiseco Pistons way back when the LT1 came out and we where all freaked out about that "scooper" on the top of the piston....and so where they....we assumed it was there for cold start and if it was eliminated it wouldn't start and run....

When we built the 427 with the Camaro we needed a -21cc dish to get the compression down to work with the boost we where going after...well...it needed a big dish so bye bye scooper. The car actually starts better then a stock DI motor and we've had no issues. Also since then I found out why that scooper exists.

Its there to move fuel into the exhaust port to help raise temps to make the cat light off sooner.. sooner the cat is warm the sooner the cat works and for emissions that's a big plus. Every time we build a DI motor I can help but wonder how much that scooper effects flame travel in the chamber....

[schpenxel]

Good read

[GHuggins]

Magnuson's been testing a higher output high pressure fuel pump that's supposed to deliver another 20 or 30 percent over the LT4's and will be at SEMA this year with their new bigger blowers, but as you've already pointed out it boils down to the injectors and rails abilities to support the fuel demand... I would really like to see a hybrid setup come from GM like some manufacturers out there have gone to... This way you can optimize injection timing like the gen 4's while still having the idle and cruise efficiency of the DI... I've had some customers reporting back with up to 27mpg after I've tuned them with a CAI and tune only and I'm talking about 6.2l 4door 4wd Silverado's... Can't argue with DI being better for economy or efficiency, but it's not worth much for WOT - at least for the big HP builds - too much high pressure fuel being sprayed on cylinder walls leading to other problems in my honest opinion...

[JnJSpdShop]

For sure...we had been working with Wiseco Pistons way back when the LT1 came out and we where all freaked out about that "scooper" on the top of the piston....and so where they....we assumed it was there for cold start and if it was eliminated it wouldn't start and run....

I also heard from various sources that it was indeed for cold engine starts. Glad to hear you disproved the theory

[Joshtuning]

Pretty awesome write up

[Redline MS]

Magnuson's been testing a higher output high pressure fuel pump that's supposed to deliver another 20 or 30 percent over the LT4's and will be at SEMA this year with their new bigger blowers, but as you've already pointed out it boils down to the injectors and rails abilities to support the fuel demand... I would really like to see a hybrid setup come from GM like some manufacturers out there have gone to... This way you can optimize injection timing like the gen 4's while still having the idle and cruise efficiency of the DI... I've had some customers reporting back with up to 27mpg after I've tuned them with a CAI and tune only and I'm talking about 6.2l 4door 4wd Silverado's... Can't argue with DI being better for economy or efficiency, but it's not worth much for WOT - at least for the big HP builds - too much high pressure fuel being sprayed on cylinder walls leading to other problems in my honest opinion...

I think your going to see some interesting developments in DI hard parts by April......

[GHuggins]

We just talking about rails, pumps, injectors, pistons and things of this nature or whole new hybrid systems

[Chevy406]

I feel quite humbled after reading Howard's articles and the conversation here. The realization that the more I learn, the more I find how much I don't know was never quite so brutal.
Very appreciative of the guys that are willing to share their knowledge with us part-timers.