Discussion
xrtim said:
It’s an LS1 4.8 twin turbo which I built with quite a few mods, most of the fabrication has been done by myself (exhausts, intake, dry sump and water meth tanks) running Megaquirt MS3 Ultimate staged injection (16 injectors) boost and traction control
What turbos are you running again? Sorry I can’t remember. Can’t wait to see the final dunk numbers for this car. Should make stack of power.
Is it an iron or ally block? Have you thought about getting a ally 5.3 block? Any reason why not? They run the same bore I think. The 4.8s just run a shorter stroke (I think and could be wrong).
chuntington101 said:
What turbos are you running again? Sorry I can’t remember.
Can’t wait to see the final dunk numbers for this car. Should make stack of power.
Is it an iron or ally block? Have you thought about getting a ally 5.3 block? Any reason why not? They run the same bore I think. The 4.8s just run a shorter stroke (I think and could be wrong).
Turbo's are Holset HX35, 120mm Twin Scroll housing, should start boosting around 2800rpmCan’t wait to see the final dunk numbers for this car. Should make stack of power.
Is it an iron or ally block? Have you thought about getting a ally 5.3 block? Any reason why not? They run the same bore I think. The 4.8s just run a shorter stroke (I think and could be wrong).
Its an Iron block got a great deal from Summit Racing for a new block and at the time when I researched Iron vs Aluminium I read quit a few posts saying that at around 800hp the liners become unstable so iron it was, 4.8 uses shorter stroke crankshaft than 5.3 but same bore, changed the reluctor wheel to a 58 tooth, decided to go with shorter stroke for the extra rpm potential it provides, figured that the motor wont be struggling for HP or Torque. Took a while to sort out forged rods and pistons as I wanted to use flat top pistons not dished, research went on and on until I got there
I think I will stay with the iron block at $350 for a brand new finished honed block is unbelievable (+tax and shipping) and if I wanted the car lighter I could always look in the mirror, quite a lot to loose there. Turbos are good for 600hp each and I wouldn’t want to rev past 7500rpm although internals fitted could probably go higher
^ Thanks, makes sense. When I built my first turbo ls1 I used the truck heads (fitted with ls6 sodium exhaust valves) to lower the compression. I also paid out a fortune to have custom pistons made with a dish which mirrored the quench pad in the head. I sent the manufacturer a piece of cardboard cut to shape :-) Compression was quite low but I had the option of fitting stock ls6 heads to raise it 2 clicks.
Can't believe it, motor started on fist attempt admittedly running quite rich but Megasquirt started to autotune that down a bit before I had to shut down. Had a couple of small fuel leaks from the fuel rails and an oil leak from the turbo return but over the moon its all working. Alot of tuning ahead to get it running nice but sounds awesome.
After I sort that, its engine out and get the body ordered, I'm being drawn to the dark grey with gold wheels, it will be nice to get back to ordering parts and installing them rather than custom fabrications all the time
After I sort that, its engine out and get the body ordered, I'm being drawn to the dark grey with gold wheels, it will be nice to get back to ordering parts and installing them rather than custom fabrications all the time
Been held up for some time, after engine start found out that the alternator wasn't working so after a bit of research decided on an uprated version from Mechman and it just happens that the 240 amp billet polished one wire LS version was on offer. It has just arrived and looks great, shame it won't be seen in the engine bay. All I need to do now is change out the battery wiring for 335amp cable and check to see if I need a shorter belt as it uses a smaller pulley, we will see 
And a little bit of welding, charge cooler feed pipe just needs cutting to length and a screw tip welding on, alternator needs new mount making as the mounting holes are slightly different, hopefully by the end of next week I will be back where I started with a running engine ready to continue tuning 
Thank you
I'm working on the chargecooler pipe work at the moment and have remade the Ultima heater bypass assembly as I am unhappy with the fit in the engine compartment and because my installation has the pipe work routed to the rear and into a gearbox oil laminova cooler/heater and re routes to the opposite side of the engine bay back to the bypass assembly. Picture is off the new assembly
I'm working on the chargecooler pipe work at the moment and have remade the Ultima heater bypass assembly as I am unhappy with the fit in the engine compartment and because my installation has the pipe work routed to the rear and into a gearbox oil laminova cooler/heater and re routes to the opposite side of the engine bay back to the bypass assembly. Picture is off the new assembly
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