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Vt 5l not going as expected

Ash 5l vt commy

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Hi All,
I hope ive posted in the right section, just wondering roughly what hp my 5l should be around,

Standard stroke 5l
Full rebuild, with arp studs
Flat top pistons, 0 deck height
41433rh cam - [email protected], 110 lobe seperation and 607/603 lift roller cam
Crow timing kit, lifters, roller rockers
Fully recon heads machined for double valve springs, but no porting
Edelbrock air gap manifold, 4 barrel throttlebody
Greentop ls1 injectors

Maffless tuned with kalmaker and only made 230rwhp, does this sound right?
Thanks
 

immortality

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That does seem a bit low. Fit a small open spacer under the throttle body, those manifolds have a slight distribution issue which a open spacer fixes. What fuel was it tuned on?
 

Ash 5l vt commy

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Hi Thanks for all the fast replies,
3.45 diff grears 3000 stal, auto
Ill try dind the dyno sheet tonight, it was also tuned only on 91 octane, tuned by alan gibbs at kalmaker perth
Very keen to try that spacer idea,
Thanks for replies
 

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Your problem is the fuel. Should have been tuned on 98. With flat top pistons and zero deck with VT heads (59cc chamber) you are over 10:1 compression.
 

Ash 5l vt commy

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Ok so you think fuel is the whole problem? Would head work be advisable as well?, another thing was it loved timing ran best at 32 deg, thought it was cam timing but double checked it and it is corect, thanks again
 

Deuce

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No real need for headwork at this stage.
Try the spacer, better fuel and a retune before you look at any major work.
What exhaust? Good headers and twin 2.5" system?
 

Ash 5l vt commy

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Thats the next thing on my list, it still has stock headers, the back half of the is twin 2.5 inch, but the front section with the cats are not, not sure what size but definately smaller than 2.5 inch, i will do that next, thanks
 

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Ok so you think fuel is the whole problem? Would head work be advisable as well?, another thing was it loved timing ran best at 32 deg, thought it was cam timing but double checked it and it is corect, thanks again
That doesn't sound right at all. What is the base timing on the dizzy?

The VT heads have a more efficient chamber and generally require slightly less timing coupled with the higher CR it probably shouldn't need that much total timing in it. The fact it takes that much timing on 91 makes me think something else isn't right.

Have you done a compression test?
 

Ash 5l vt commy

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The other thing i remember the tuner saying is the map sensor wasnt reading a even pressure it was jumping around alot, tryed a new position and a new map no change?,
 
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