My dyno results - what's holding the car back?

[Odin_S]

Just over a week ago I got my car on the dyno. Not as high as I though given the spec. My temps were fine. Just felt the car was holding back. I got 311bhp at the wheels at 1.4bar

I'm thinking it's the map. Although safe I think unless you know about 3S-GTE it will be conservative in mapping. Abbey Motorsport did mine but they are mainly Nissan specialists. Anyway enough from me here's my spec. I've got a 4 bar map sensor for which I'll maybe take the boost up to 1.6 but I should I think have had more for 1.4bar

Garret Gt3076R on standard manifold 63AR I think
Wossner 8:0.1 pistons standard conrods
800cc sard
Link G4
Phoenix Power intercooler

[ashley]

What cams? Looks like they might need dialing based on the drop in initial torque you're getting after it's come on boost

Any idea what your EGT's look like?

[Odin_S]

Standard rev 3 cams. I'm unsure of EGT. That exhaust temps? The WG is plumbed back into the downpipe

[jimGTS]

id say they've mapped it on the lean side of "safe" imo.

"safe" afrs are low 11s, high 10s really, you are at the upper end of what some people would regard as ideal. ideal folks say 11.5. anything more is getting on the lean side for a boosted car on pump fuel.
least your RED run, your best is in the high 11s, not the 12s i can see in BLUE.

also, bare in mind thats 310-ish at the hubs, not the wheels. so maybe 350 flywheel at best and it does peak at 1.5bar going by the graphs for your RED run.


got to be a timing issue or silly high intake temps (which you said it isnt).
i would look at cam and ignition timing. (if either of these are out, you will need to look into remapping again).
or even worn ignition components could be causing issues.

both can be easily looked into though.

edit
or could just be lazy mapping, which i hope it isnt.

[Odin_S]

I'm thinking it's the timing hence why I said need a Toyota mapper.

Ignition is all new including spark plugs. I asked for 1.2bar low and 1.4 bar high. Add I'm still on 2.5 map sensor. AVC-R is controlling boost

[Odin_S]

I just remember on your rev 5 Jim you got a lot more at just 1.3bar. I know you had HKS cams.

Can someone Luke from Pacific Work check the timing? Or is it the person mapping? I'd much rather Luke do it.

[jimGTS]

with timing we can talk about a number of possibilities.

mapping, the mapper isnt advancing timing much, either due to det/knock, or because they dont know the 3sgte well. this is a mapping category.


physical timing, ie the camshaft timing is wrong, something luke can double check, same goes for "base" ignition timing. this alsoneeds to be set correctly, physically. i would be more comfortable with someone who knows 3sgte's do this.

mapping, someone who maps celicas/mr2 also in an ideal world.
most mappers can map most things, but depending on quirks with the engines, ecu's, it can be a mine field getting the combination right if they dont have much experience of that platform.

[ashley]

I reckon you might need to advance your inlet cam by 1 tooth, I would defo be checking the cambelt is timed up correctly- that double dip don't look right. I thought it might be the boost backing off too much once the waste gate opens, but looking at your boost plots it doesn't dip that far

As Jim says- I'd be checking the basics first- static ignition timing is a good call as well...then back to the dyno.

Out of curiosity- was this on fresh 99ron fuel??

EGT = exhaust gas temperature, it's a good indication of back pressure- you mentioned you're on the smallest GT30 housing, so you might find EGTs are pretty high...but I'd expect you to be alright up to 1.5bar unless something else is happening. What exhaust do you have (what bore is it all the way through)?

[Odin_S]

I reckon you might need to advance your inlet cam by 1 tooth, I would defo be checking the cambelt is timed up correctly- that double dip don't look right. I thought it might be the boost backing off too much once the waste gate opens, but looking at your boost plots it doesn't dip that far

As Jim says- I'd be checking the basics first- static ignition timing is a good call as well...then back to the dyno.

Out of curiosity- was this on fresh 99ron fuel??

EGT = exhaust gas temperature, it's a good indication of back pressure- you mentioned you're on the smallest GT30 housing, so you might find EGTs are pretty high...but I'd expect you to be alright up to 1.5bar unless something else is happening. What exhaust do you have (what bore is it all the way through)?

Car is always run on 99ron, in this case v power. 3 inch downpipe and exhaust

[ashley]

Fair play, unlikely to be back pressure issues at that boost level then...back to the drawing board

[jimGTS]

how was the engine run in out of interest?

some revs and small amount of boost i hope.

[Odin_S]

The car is running fine on boost. Idle still needs a small tweaking. The fluctuations are less than the last map.

[abovetherim]

I'll just throw this in the mix even tho I know nowt about turbos but...

In this months practical performance Dave walker was mapping an mr2 turbo and had problems with the MAP pulsing. Solved with an inline fuel filter.

[kev8611]

Please delete

[ashley]

I had a similar double dip until we swung the cams

[Kongaroo]

Can you connect to the ECU with your laptop and look at the ignition timing you are running under boost?

If it's particularly low - like maybe between 10 to 14 degrees then you may well have your answer.

If the timing figures look reasonable then maybe need to check your base timing is correct?

[kev8611]

Please delete

[Kongaroo]

error - wrong thread - pls delete

[jimGTS]

This is very similar to mine except i made 330 but only 260 odd at the wheels.

I have the same dip in my graph too.

260 at the wheels with a 3076?

[kev8611]

Please delete