Weird RR results, opinions please.

S

skiddusmarkus

Active Member
Had my car mapped at Fusion on saturday and it was throwing out some weird results.Spec is a forged engine with mostly Tomei parts and a turbodynamics md214(basicly a gt2876).Car has fmic and water injection,oil cooler and massive sard rad fitted so temperature isn't an issue.Tried it with and without WI(lost 3bhp with it on 100% water)and no noticable change to the graph



These figures are at the wheels with standard injectors more or less maxxed out (the 700ccs I took with me couldn't be used due to a damaged pintel cap).The problem is the power curve flattens out at around 5500rpm whereas it should be still climbing and the torque peaks at around 5000rpm and falls off quite quickly whereas on my old standard engine it used to peak at 4k and stay level until 6500 or so.

Ed said it was really struggling to breathe and Red Reading was there on the day and he suggested it could be that the Tomei 260 cams might need dialling in on the verniers(more specificly the exhaust cam).I just want people's opinions on what it could be as I want to get it sorted and get back to Ed's to have it tweaked and mapped at 1.5 bar or so-its only at 1.1bar atm.

Flywheel figures were 315bhp/300lbft and on the road it does feel quick but I know there's a lot more to be had and want it as the spec is wasted on such low boost.

Ed also gave me a nice ecnomical part of the map around 60-70mph and I managed to get 38mpg driving home compared to 30mpg on the way down, both times driving like a nun with absolutely no boosting at all.
 
P

pulsarboby

Guest
engine timings out i reckon
set the vernier pulleys to 0 initially it should make good power at that.
have you put a strobe on it to check ign timing? thats generally a good teller if the engine timing is out as youll have trouble getting 20 degrees btdc if its out
 
red reading

red reading

Active Member
There was no problem with timing it up bob, i think it is the exhaust cam is retarded slightly. that graph simon has posted is 266.7bhp at the wheels not the fly. simon i said that you'd get 38mpg ish when its been mapped thats what i get on a off boost run......... it's better than the wife's 1.4 astra

And bob the pulleys are 0'd
 
P

pulsarboby

Guest
ah right
actuator not holding???
or maybe because injectors are maxed out as said, could be a number of things really
 
S

skiddusmarkus

Active Member
Actuator was holding a steady 1.1, peaking at about 1.2 initially.I am probably going to get a 1bar+ one though as its only a 0.65 bar actuator so might struggle with more boost.
I'd have thought the injectors being maxxd wouldn't really have affected it until higher rpm and wouldn't shift the torque curve so far to the right?It doesn't feel as laggy as the graph suggests at all but could obviously be even better.When I was picking bits for the engine I got a 5kg flywheel, all the pulleys are alloy, crank has been lightened and balanced, compression is raised with 1mm hg, basicly I did all I could to help the engine rev faster.
 
red reading

red reading

Active Member
I still think its static timing simon,that would also explain the turbine surge at tickover too,advanced inlet cam and retarded exhaust will do that in theory
 
S

skiddusmarkus

Active Member
Is there normally enough adjustment on verniers to dial in/out enough to sort this?

Its annoying as when you look at the graph it looks as if it should be making more like 350bhp on that boost.
 
red reading

red reading

Active Member
Have you still got the cam spec sheet?,because it maybe that the cam's need setting up with a degree wheel and such properley
 
Fusion Ed

Fusion Ed

Active Member
Not really helpful to the thread, but that's nice pick-up in MPG :)

Next step for me would be to pull the cam cover off and have a look visually at the cam positions, as yes it was behaving as if it had a restrictor plate on it or something.
 
gtirx2

gtirx2

Member
Stretched timing chain putting the timing out?
I had a chain that was around half a link longer than other stock chains i had once.
Cant say i noticed any performance difference,but i was using stock cams.
I threw some rockers once and that when i spotted it.
 
campbellju

campbellju

Moderators
Staff member
Simon, were you trying to raise boost past 1.1Bar or just showing what happened at this boost level? I'm far from an expert but if your actual boost was your target boost to the redline then your actuator is doing what it's meant to. Changing it if you want to go for 1.5Bar later is wise. Unless your static timing is way off then I'd have thought you need to look for air leaks to find out where your missing air has gone. What was your MAF doing? If the air volume continued to increase but your power flattened off then your intake side may be leaky.
 
S

skiddusmarkus

Active Member
I don't Danny but i will contact tomei and do some searching on the neterweb.

The timing chain was replaced when the engine was built, so has only done about 800 miles or so.
 
Fast Guy

Fast Guy

Moderators
Staff member
What air filter do you have? It looks almost like something on the intake has maxed out airflow wise and is a restriction. (although at 266bhpatw it shouldn't be the case)
Would cam timings flat line like that? I just thought they moved the whole power curve to the left or right depending which way they were out.
 
S

skiddusmarkus

Active Member
The air filter had crossed my mind too Carl.On the day I did switch from my homemade inlet and mabsolutely massive Blitz filter to a larger 3" inlet with Z32 MAF and a smaller blitz filter.I'd be surprised if it was this though as its still a fairly decent size and ultimately is now sucking through a larger diameter MAF.Its from a Skyline twin entry into single turbo setup.
I'll take some pics of the old and new when I finish work.
 
red reading

red reading

Active Member
Fast Guy said:
What air filter do you have? It looks almost like something on the intake has maxed out airflow wise and is a restriction. (although at 266bhpatw it shouldn't be the case)
Would cam timings flat line like that? I just thought they moved the whole power curve to the left or right depending which way they were out.
Click to expand...
Depends on what the cams are set at carl, in theory your correct but if you have say one cam retarded and one advanced you will not move the power you won't make it to start with!
 
S

skiddusmarkus

Active Member


The picture isn't great but gives you an idea of the size in relation to the z32 maf.It is blocked off from the front by the expansion tank and has a temporary cardboard heatshield but what you cannot see is the huge cold air feed that is directly above it when the bonnet is down fed by the sparrow slicer.
 
P

pulsarboby

Guest
i reckon i know whats wrong with this as ive seen similar thing happen before!
i bet you that when you remove the rocker cover that the hex bolts on the vernier pulleys have come loose and the timing (as danny has said) has advanced on inlet and retarded on exhaust, this will give you chatter back through the airfilter on idle and lower rpm and flatline the graph further up the rev band.
if i were you i would not drive this car any further untill you've whipped the cover off to take a look
 
You must log in or register to reply here.
Top