I'm running 42lb SVO injectors as well. No problems at all...as stated before it's all in the tune. These injectors where recommended to me by the original tuner of the engine.
My experience covers much more than just increasing the displacement. In addition to the work on the rotating assembly (0.030" overbore on the cylinders and a 3.75" crankshaft), major work was done on the intake to increase airflow. The LT1 cylinder heads were ported, so that the intake flow increased from the stock 210 CFM to 272 CFM (cu. ft. per minute) at max valve lift. The stock intake was also ported, and the 48mm throttle body was replaced by a 58mm body. To keep up with the increased airflow, the standard 22#/hr injectors were replaced with 30#/hr. The exhaust work had already been done - long tube headers, high-flow cats, and an X-pipe.
All engine builds have to be done as part of a plan. Increase just one component and the results will be disappointing, because some other part of the engine now becomes limiting. For instance, when I installed the HotCam without any changes to the intake or exhaust, my best time on the quarter increased my a measly 0.05 seconds! Then, when I changed out the exhaust, I got a full three tenths off the quarter, and the intake became the limiting factor.
Finally, to answer how the change feels, it is now scary fast. Estimated 0-60 time is about 3.4 seconds, and the 0 to 100 time is about 8.5 seconds. When I hit the gas while cruising at 30 MPH with traction control off,, the back end skitters back and forth as the car leaps forward with a screaming roar. In the quarter mile, I took almost a full second off my previous best, and increased my trap speed by 10 mph.
I have a very similar build as LT4POWR, but LT1 heads, and used his build as a guide.
I also use 42's on a 350, so you will be fine if you get a good tune.
I have a very similar build as LT4POWR, but LT1 heads, and used his build as a guide.
I also use 42's on a 350, so you will be fine if you get a good tune.
Todd it made sense to go with a proven setup, so I'm glad to know that I wasn't the only one thinking down that path! Very nice numbers on your LT1, very nice indeed.
Quote:
Originally Posted by Bluewasp
442rwhp...
Thanks Rob!........I knew it was over 500CHP, but wasn't sure what your Rear Wheel was.
How well do the AFR heads flow? Do you have any information on the heads you purchased?
They are listed at 300 at .600, and I have general info that came with the heads, but no specific flow sheet for these heads. I did talk to Tony over at AFR after speaking with AI and LE, so that had almost everything to do with my decision.
SBC 195cc-LT Comp Pkg.L98
8019 Hyd Roller Valve Spring
8mm 2.080 Std Race Int Valve
8mm 1.600 Street Exh Valve
SBC Eliminator 7 Deg.Ti Ret
Upgrd 3/8 Studs to 7/16
8mm Valve Locks- 7 Degree
LT1 Hds-Angl Mill Hds and
Quote:
Originally Posted by Bluewasp
Also, Why did you buy the AFR heads vs one of the other LTx heads on the market now..
Because after speaking to LPE, AI, and LE everyone wanted $1500 to over $2000 to take my LT4 heads and port-polish and then send my heads back, with or without a cam. For less than $1000 more, I bought a set of superior heads outright which outflow anyone's port and polish job that can be done with the stock LT4 castings. I also looked at other off the shelf heads, but for the LT4, AFR's rep was far far better (In MY research of heads), than anyone else. When I have a guy willing to sell me a set of LT4 P&P heads, because he's running AFR's on his LT4, AND the guy building my motor is telling me that he's running AFR heads but I can go with whomever I want for the P&P. Eventually you have to question what is being said to you. There's a reason that AFR's are replacing stock head castings all over the place. But when I made a change to the AFR's, because of the superior combustion chamber my rods and pistons had to be changed. SO, IMHO, it was about getting the most bang for the buck, maximizing efficiency of the motor and only having to do it once.
Noland
Last edited by BlackHarleyMan; 06-10-2008 at 05:32 PM.
You guys with the 383's and 30/42 lb injectors: what fuel pumps are you running? Stock? Walbro 190? 255?
Walbro 255, but it actually wasn't really needed. I wanted to replace the pump and happened to get one at a good price. I watched the FP with the stock pump and it held fine all through the RPM range.
You guys with the 383's and 30/42 lb injectors: what fuel pumps are you running? Stock? Walbro 190? 255?
+1 for the ford 30 lb injectors. I am running the stock pump. I have been told that the ford 30lb injectors flow about 32lb on the Vette due too a little higher fuel pressure than the Mustang.
__________________
1996 LT4 383 All forged, Eagle 3.75 crank, Eagle 6.0" Rods, Mahle Forged Pistons, 11.0:1, Comp XFI 467, Ported factory LT4 heads, PAC 1518 Beehives, TFS Hardened 7.100" push rods, Comp Pro Mag rollers, Double Roller chain, Guide plates, Elec. water pump, Keyed balancer hub, TPIS Long tubes no cats, no resonator, Magnaflow. M/T ET Streets.
But when I made a change to the AFR's, because of the superior combustion chamber my rods and pistons had to be changed. SO, IMHO, it was about getting the most bang for the buck, maximizing efficiency of the motor and only having to do it once.
Noland
This may be a stupid question, but why did you have to change pistons and rods when you decided to go with the AFR heads? Compression ratio?
This may be a stupid question, but why did you have to change pistons and rods when you decided to go with the AFR heads? Compression ratio?
Your car is going to be nasty dude........
Yes mainly for the Compression ratio. AFR didn't want to cut the heads downto 55cc. If we used the pistons I orginally speced for the stock heads (Wiesco 20cc dish) it wouldn't have had enough compression.
Moving from the 5.7" rod to a 6" rod was 2 fold. Mainly because, honestly the only really nice pistons (with the correct dish) I could get him a deal on at the time were the Manleys and they were for a 6" rod... but since the AFR heads have a very eficient combustion chamber, I knew I get away from the shorter 5.7" rod (orginally speced because the faster piston speed on and of TDC reduced the chance for detonation) and take advantage of the less side loading of the longer 6" rod, without having to worry about detonation.
I also knew I would need to change the cam lobes to take full advantage of the new AFR heads and I could juggle the Intake Valve Closing point around a few degrees to help compliment the long rod and its slower piston speed/longer dwell time at TDC.
OK, JUST to let YOU know..........Alot of the research on this build came from your combo!...........You send me the specs on your engine awhile back and I've used it as a template for this setup! SO, Thanks to you, here I sit BROKE AS A JOKE!.......Thanks!
Noland
P.S. I would love to see your dyno sheet if you have one for your motor. When I saw your combo, I knew that if a stock bottom LT4 could make that type of power and be driven daily, then a stroker would kick Azz!
N
Quote:
Originally Posted by 95wht6spd
I have a very similar build as LT4POWR, but LT1 heads, and used his build as a guide.
I also use 42's on a 350, so you will be fine if you get a good tune.
Thanks guys, and no problem
I'm actually thinking about doing a 383 this fall/winter, so this thread has me really interested.
I've got my dyno sheet scanned, but it's pdf and photobucket is giving me problems uploading it...if someone PMs me their email, I'll email it to them and they can host/post it.
Quote:
Originally Posted by Mojave
You guys with the 383's and 30/42 lb injectors: what fuel pumps are you running? Stock? Walbro 190? 255?
I'm still running the stock fuel pump.
__________________ 1996 LT4 Corvette 416rwhp/375rwtq (SAE) - NA Stock Bottom End
416rwhp/375rwtq (SAE) - NA Stock Bottom End 
