Whats wrong with this combo
Thread Starter
Teching In
Joined: Feb 2009
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Whats wrong with this combo 408 lsx block, 240/240/112lsa 600lift cam, 9.1 comp, l98 heads ported/ polished, patriot gold springs, 1.7 yella terra rockers, morel link bar lifters, fast 102 mainfold, 92mm thottle body, 60pound injectors, ase twin walbro surge tank set up , ase t-1000 turbo kit .76 front . 1.3 rear housing, turbo 400 9.5inch tce 4000rpm converter, 346 gears true track, makeing no power on dyno 320rwkw on 7psi 280rkw on 15psi but sounds real strong mixtures 11.5 i have played with timing rangeing from 8degrees to 14 comp tests has even 150kpa its a fresh motor, on my dd dyno it does 6800rpm at 190km which is low but converter feels real tight like u woundn't know it has one but the dyno graph pulls hard 2 a little over 4000rpm then starts 2 break down by the graph but engine sounds strong boost pressure even , spark etc it feels good on the road but its hard 2 get traction etc thanks for any ideals help u can provide as its doing my head in. also runing street e - boost.
9 Second Club
Joined: Nov 2003
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From: Norn Iron
If traction is a real problem, then assuming you have decent tyres etc then clearly it is making more power than the dyno suggests.
But there are lots of variables. Who is tuning it, and what are their thoughts ? ( or the dyno operators ? )
Plus, track performance may be a better indicator of power, than going by dyno comparisons with other people.
By the numbers you give, it sounds like you are on Aus, and not the US. DD numbers will often be much lower than many US dynos which makes comparisons misleading too.
The drag strip doesnt tell lies though, especially trap speed.
But there are lots of variables. Who is tuning it, and what are their thoughts ? ( or the dyno operators ? )
Plus, track performance may be a better indicator of power, than going by dyno comparisons with other people.
By the numbers you give, it sounds like you are on Aus, and not the US. DD numbers will often be much lower than many US dynos which makes comparisons misleading too.
The drag strip doesnt tell lies though, especially trap speed.
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Joined: Jan 2004
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From: New Zealand
408 lsx block, 240/240/112lsa 600lift cam, 9.1 comp, l98 heads ported/ polished, patriot gold springs, 1.7 yella terra rockers, morel link bar lifters, fast 102 mainfold, 92mm thottle body, 60pound injectors, ase twin walbro surge tank set up , ase t-1000 turbo kit .76 front . 1.3 rear housing, turbo 400 9.5inch tce 4000rpm converter, 346 gears true track, makeing no power on dyno 320rwkw on 7psi 280rkw on 15psi but sounds real strong mixtures 11.5 i have played with timing rangeing from 8degrees to 14 comp tests has even 150kpa its a fresh motor, on my dd dyno it does 6800rpm at 190km which is low but converter feels real tight like u woundn't know it has one but the dyno graph pulls hard 2 a little over 4000rpm then starts 2 break down by the graph but engine sounds strong boost pressure even , spark etc it feels good on the road but its hard 2 get traction etc thanks for any ideals help u can provide as its doing my head in. also runing street e - boost.
are you hitting a reduced power mode, any codes comeing up ?
maybe valve float at 15 psi, what springs/seat pressure are you running ?
Maybe the 408 is chokeing the turbo up top (turbo to small).
First, I dont think that a 60# injector is enough to support 15 psi of anything on a 408.
Can you post the graph? You could be severely blowing thru the converter on the dyno at that power to load in the top of 3rd. Are you actually making full 3rd gear pulls on the street? I would think that you would be able to feel that immediately.
Can you post the graph? You could be severely blowing thru the converter on the dyno at that power to load in the top of 3rd. Are you actually making full 3rd gear pulls on the street? I would think that you would be able to feel that immediately.
Thread Starter
Teching In
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Hi guys, thanks for ur help, we do our own tuning etc with efi live on our own dyno , dyno pulls are done in top gear from 2500/3000 n turbo 400 with 3.46 diff gears i see 190km at 6800rpm ( which i feel is low) a/fs are 11.5 have tryed different amounts of timing ie from 8-14 degrees converter is 4000rpm stall so i have even tryed starting a run at that speed , It dos look like a valve spring prob by the chart but they are brand new and engine builder asssures me pressures were check etc spark gap is .8 if springs were a problem would mainfold pressures be all over the shop. I'm located in oz . also injectors duty cycle hasn't been any were near 80% it has a pretty good fuel system intank walbro pump feeds custom external surge tank with 2 600hp walbros and also has a return line fitted pressure dosn't drop under 60psi. regards Jason
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A 60# injector can only deliver so much fuel. No matter how good the stuff behind it is. A 408 that is really consuming 15 psi should make well over 700 to the wheels which should be pushing them static. The fact that you haven't seen the 80% IDC means that you aren't either making the power or the load. The fact that you are starting a pull over 4K RPM with a 4K stall doesn't matter. If you are blowing thru it, the converter is eating up all your engine power. Was the converter custom built for this application or was it carried over from somewhere?
What do you mean by manifold pressures all over the shop? Is boost fluctuating really bad?
What do you mean by manifold pressures all over the shop? Is boost fluctuating really bad?
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Verdad Gallardo Thread Starter
Teching In
Joined: Feb 2009
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Hi, ya right about the injector size etc but its not makeing the power if i was makeing the power ie 700rwhp they will be maxed out but i feel the dyno is pretty right as i took it for a good drive out on the open road it feels strong but not 700hp strong and boost keep spiking to 15psi when i have it on low boost for i think the trans or converter is slipping etc but i dosn't feel like a flat out slip if that makes sense the motor/ box / converter have all been built to handle 15psi 800rwhp , maybe any transmissiong / converter specialist may be to jump in and give a few ideas is there any thing in a t400 that could be incorretly fitted etc to cause this?, its a full manual box etc , i meant that boost pressures inside the intake manifold would be all over the place if i have wreak valve springs etc but they are nice and even on the dyno at least on the road i feel the trans converter is causing it 2 spike etc.
