When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi everyone I am from the UK and looking for some advice and routes to go.
i have Opel Astra J Vxr which has LHU engine which is basically the same as the LNF which was running 415hp / 420 lb-ft at 1.8 bar but dropped it to 1.6 bar till I sort the problem and all on pump gas. I bought it from new in 2012 and currently on 38000 miles.
There’s only 2 or 3 running this power in the UK so not much info to go on.
my spec,
tubular Manifold with EFR 7163 turbo
Turbo back with no cats,
Airtec intercooler,
Pro alloy Radiator,
EP induction kit,
Fully Forged Engine,
Stage 2+ cams,
Stage 4+ clutch,
Uprated Valves and valve springs,
Balancing Shaft Delete,
HPFP
When the car is being live mapped on the dyno there’s a slight misfire round about 5500/6000 rpms so makes a dip in the graph at the end.
My tuner is saying either the coils or the sparks plugs or both are not up to the job so been looking at ZZPs coil packs and ACdelco plugs, would use recommended these? Or what plugs and coils would use recommend?
the coils and plugs have been changed twice already and still the same result. On standard coils and NGKs plugs.
Pictures to show what my car looks like and what I have done to it. Also what the plugs look like after about 6000miles.
Last edited by briangorman; 02-18-2018 at 10:51 AM.
Brilliant thanks for that, Will message my guy and see what it’s running then hopefully get it in during the week to see if that helps. Will report back once it’s done.
Thanks for your help. My car was running 0.82 lambda with stock gap for plugs but got the car mapped today with it running 0.85 lambda and a gap of .028” for the plugs and now has sorted the issue.
it made 413bhp, the graph above shows it hits a wall and doesn’t keep climbing. Stays at 413bhp for most of it.
does the power sound right for what I have done to the car?
if not would it help by raising the fuel pressure as that’s still at stock?
or possibly the injector could be slightly out of sink?
low-mid range is all good but when it gets to the high end it just doesn’t want to give anymore.
Last edited by briangorman; 02-26-2018 at 10:02 AM.
Here is the GM Stage 1 fuel pressure table. You need to be logging commanded pressure vs. actual to make sure you aren't running out of fuel if you do raise the pressure.
As for what to bump it up to, I'd try bumping it up just a little and see if it can meet that pressure. I would start with 16 max and see if it changes.
Here is the GM Stage 1 fuel pressure table. You need to be logging commanded pressure vs. actual to make sure you aren't running out of fuel if you do raise the pressure.
As for what to bump it up to, I'd try bumping it up just a little and see if it can meet that pressure. I would start with 16 max and see if it changes.
Thanks a lot for all that info.
Originally Posted by umrdyldo
Also which HPFP are you running?
If you are truly running out of fuel then switching to the LT1 direct injection pump might be your next step.
I doubt you are running out of fuel though.
actually I have a ASNU fuel pump which is in the tank and that does the low pressure side. I still have stock pump for High pressure side. I take it the next step is to change out the High pressure side?
actually I have a ASNU fuel pump which is in the tank and that does the low pressure side. I still have stock pump for High pressure side. I take it the next step is to change out the High pressure side?
Yes
If you do find you are actually running out of fuel, contact mongorat427 on here.
He installed the Corvette LT1 and LT4 high pressure pump. I think you need adapters but I'm not 100% sure. The LT4 runs much higher pressure and flow than the LT1 or LHU HPFP. https://www.cobaltss.net/forums/2-0l...l-pump-324991/
I am not sure if he has test fit one to other platforms but I'm guessing it works just fine.
If you do find you are actually running out of fuel, contact mongorat427 on here.
He installed the Corvette LT1 and LT4 high pressure pump. I think you need adapters but I'm not 100% sure. The LT4 runs much higher pressure and flow than the LT1 or LHU HPFP. https://www.cobaltss.net/forums/2-0l...l-pump-324991/
I am not sure if he has test fit one to other platforms but I'm guessing it works just fine.
thanks a lot for that. How much are the HPFP? As ZZP have a direct fit one for $700. What one would you recommend?
Last edited by briangorman; 02-26-2018 at 04:42 PM.
So went to get the car finally mapped today and it went all bad. Done 1 dyno run to check if it was all ok but was down a little power then done 2-3 other runs and by the end of it was down 80bhp. So turned the car off then turned it back on and was a really loud knocking noise so engine needs to be fully stripped down now to check crank, rods, pistons etc to see what the damage is.
Is there a uprated crankshaft for it? And also is the oil pump good enough to run this power or does it need uprated?
ur gap is to big. I had bad blowout at stock gap on my 257. lower to .028 like stated. and lean out ur lambda to .87. even .85 is rich .87 is just fine. even .88 is good.
ur gap is to big. I had bad blowout at stock gap on my 257. lower to .028 like stated. and lean out ur lambda to .87. even .85 is rich .87 is just fine. even .88 is good.
My new plugs were gapped at .028 and lambda is .85
do you know if there is an better oil pump or is standard fine?
Engine is warped etc so fucked, looking at getting the shell of an engine, rods and piston.
think it was down to an oil issue so getting to warm. Is there any upgraded oil pumps? Looking at fitting a oil cooler aswell.
is there any better design than the plastic guides for the timing chain?
What the check happened. I have similar issue at same rpm. Popcorn backfire though. Dont Think nothing is broke though. How did ur rod break
the oil lines run very close to the turbo so reckon the oil got cooked before it went into the engine, So all the lines are being relocated along with new engine etc.
Aftermarket rods broke and the crank got trashed, can't say I've seen that happen a whole lot. How high were you revving it? I've done several dyno pulls before and never had issues. Can't believe you trashed the engine just doing that. What kind of power were you making? Was the clearance in the bearings too tight?
Aftermarket rods broke and the crank got trashed, can't say I've seen that happen a whole lot. How high were you revving it? I've done several dyno pulls before and never had issues. Can't believe you trashed the engine just doing that. What kind of power were you making? Was the clearance in the bearings too tight?
yes all trashed and engine is warped aswell. Revs were set at 7k. I was only making 420bhp, should of been a lot more but just wouldn’t make the power. That could of been a possibility but not sure. There’s some serious heat damage so reckon was down to that and cooked the oil.
the oil lines run very close to the turbo so reckon the oil got cooked before it went into the engine, So all the lines are being relocated along with new engine etc.
02-18-2018, 10:43 AM
