View Full Version : Flat in higher gears
this is from a while back really, but basically at pod i ran a 12.9 1/4 but was pullin 89mph at 1/8 mile with terminal at 105mph, so you can see its dying in the higher gears.
the exhaust system i currenlty have is a single box side exit, full turbo back stainless 2.5" system, BUT the current decat is a magnex silenced effort that is only 2"
car is 1994 clio 16v, f7p 1.8 turbo running 254bhp @15.5psi
so my theory is the decat is restricting the breathing in the top gears, i have a straight through 2.5" pipe, stickin that on likely to cure my woes?
any input or other possible causes much appreciated
cheers
Ben
Adam 005
15-01-2009, 22:17
is 105mph that bad:confused:
is 105mph that bad:confused:
not bad for a gtt! could be higher with what he's running though
for a 12 second 1/4 mile its not great i dont think, and as said in the last 1/8 mile it only went from 90 to 105, after 0-90mph in first 1/8 mile?it also felt flat if am honest
for comparison a throttle bodied f7r powered mark 1 16v clio did 13.3 @ 109mph
Rob@Backyardracing
15-01-2009, 23:21
Ive seen your times and slip times and does look like your losing at top. I wouldnt just put this down to just your exhaust imo, ok you may not have best system on there but you should see this in other gears if it was restricting you thats if you rev to same rpm.. at your power id expect to see 107-110 poss?
you won't have had 254hp when you did 105mph, but maybe that was caused by something going wrong in 4th gear. do you watch AFR's up there ? and I don't mean on a dyno, I mean for real on the drag strip, or road at least. It might be leaning off ? 90mph in the 1/8th is respectable and pretty true of 250hp, so a problem up high for sure.
Rob@Backyardracing
15-01-2009, 23:34
I would have thought more the same too with that one scoff... looking at 1/8s its pretty good going...
Ps cheers for the rim Coops, what a mission that was to get over to you other night :( felt like forever on them B roads....
Andrew Cooke
15-01-2009, 23:47
it could also be charge temps, I agree with the others, it's something that's changing during the run that's restricting power over time rather than something consistent like a restrictive exhaust.
The decat prob won't help, i remember when i had my Rover coupe, it had a magnex back box, it went from a 2 1/2 to 2" through the rear box, i had a powerflow backbox made up & straight away it was up on power, noticably on the road on the way home !
Do you run a chargecooler? If so is it a Pace jobby?
I had one of them on my old GTT & ditched it from a FMIC which made alot of difference also (the Pace unit really is a crock of ****e IMO)
The lads are right, with a true 250bhp you should be seeing 110 traps...
Just a thought.. Is your cam timing out slightly or retarded/advanced ??
Andrew Cooke
16-01-2009, 13:12
The decat prob won't help, i remember when i had my Rover coupe, it had a magnex back box, it went from a 2 1/2 to 2" through the rear box, i had a powerflow backbox made up & straight away it was up on power, noticably on the road on the way home !
Do you run a chargecooler? If so is it a Pace jobby?
I had one of them on my old GTT & ditched it from a FMIC which made alot of difference also (the Pace unit really is a crock of ****e IMO)
The lads are right, with a true 250bhp you should be seeing 110 traps...
Just a thought.. Is your cam timing out slightly or retarded/advanced ??
Steve, what you say about the Cat is right, but you're missing the point that the engine has less power at the 1/4 mile than it does at the 1/8, at the 1/8 it's making good power.
Steve, what you say about the Cat is right, but you're missing the point that the engine has less power at the 1/4 mile than it does at the 1/8, at the 1/8 it's making good power.
Ahh so prob out of the pace core's cooling efficiency then ??
You'd be outside the Pace core's cooling efficiency at anything other than idle...
You'd be outside the Pace core's cooling efficiency at anything other than idle...
Lol, yeah, i reckon Mart, i tried one a while back & they are deffo over-rated IMO (& yours)
I good FMIC is alot better.
Lol, yeah, i reckon Mart, i tried one a while back & they are deffo over-rated IMO (& yours)
I good FMIC is alot better.
Thats if you got space and want to cut the front end apart :(
Is it the core which is the let down or the cooling of the water. Im hoping the rad because ive changed that for a lot better one now.
Lol, yeah, i reckon Mart, i tried one a while back & they are deffo over-rated IMO (& yours)
I good FMIC is alot better.
And my what?
And my what?
Basically he is saying your over-rated :laugh:
Basically he is saying your over-rated :laugh:
Yeah, what Dale said :wasntme:
The pace units are over-rated, i thought you felt the same about them :crap:
okay so its possible leaning off or charge cool issue
yes its a pace setup, but i really dont want to hack up the front of the car with a big gay as **** intercooler, they look dreadful imo and i refuse to hack up my bumper. is there anyway i can improve the efficiency of the chargecooler?different coolant in it?wet jet the cooler rad? anything at all?
i dont know about the ignition timing, the car is set with a generic off the shelf fastchip and on the rr days its been to the fuelling is okay but not great, doesnt lean off to my knowledge, but it may do so in 'real world' conditions granted. would a proper live map help? and if so would it need to be live mapping on road and as such stand alone? of could it improve with a remap on current managment on a rr?
obviously with other areas screaming for cash also i dont have an unlimited budget to work with but would ideally like to at least feel like its pulling up the strip after the 1/8 as i was shocked when i did first run and i didnt get told i'd need a helmet due to clocking over 110 trap if am honest
cheers
Coops
oh n rob, no danger mate, as u say bit of a trek but decent roads at least!lol
Not so sure it is a charge cooling issue causing your top end prob's, but if you're thinking of swapping out your cooler anyway, give DaveAVT (or whatever he's called these days) a shout & enquire about one of the PWR charge-coolers...
http://www.advancedvehicletuning.co.uk/avtpwr.htm
Andrew Cooke
17-01-2009, 09:12
Sounds like it's time to stop guessing and start measuring. Get yourself a K type thermocouple with a thin wire probe and a chap multimeter with a K type input. You'll be able to use this to first measure the charge temp, then the charge cooler water.
Then either get, or borrow, a wb lambda - ideally plugged onto your down pipe, and see what the fuelling is doing.
Test kit sounds expensive, but it's cheaper than blindly trying to fix things that may not be a problem.
this looks fun
http://cgi.ebay.co.uk/2-K-Type-Digital-Thermometer-w-Thermocouple-Sensors-b_W0QQitemZ330299820405QQcmdZViewItemQQptZLH_Defau ltDomain_3?hash=item330299820405&_trksid=p3286.c0.m14&_trkparms=72%3A1298|66%3A2|65%3A12|39%3A1|240%3A13 18
the sensors need swapping for something else though, a bit like this
http://cpc.farnell.com/labfacility/kmi-1x500-iec/k-type-temp-probe-1mm-500/dp/SN35290
Admittedly on my 1.4 pushing 200hp but when i did a bit of a blast with the CC on the water was almost to hot to touch.. I know for a fact, as soon as i changed to a FMIC it made a noticable difference, i didn't measure charge temps on the CC but the intercooler was 37-40 deg on boost of 24 psi manifold...
I think it's said the water inlet/outlets are a bit on the small side, as well as the water tank...
turbo ted
17-01-2009, 12:31
allright steve l hows it hanging
i run your old charge cooler with a single intercooler and have no problems infact it runs to cool so this year i be running charge cooler on its own i can't see how a charge cooler would over heat in 12 sec run.around a track it would be useless but for short runs that whats its designed for:burnrubber:
allright steve l hows it hanging
i run your old charge cooler with a single intercooler and have no problems infact it runs to cool so this year i be running charge cooler on its own i can't see how a charge cooler would over heat in 12 sec run.around a track it would be useless but for short runs that whats its designed for:burnrubber:
I ran it on it's own, i'd be interested to see the results without the intercooler Rob :)
I may come up for pod day just for the crack & 'borrow' a car :)
i know it isnt the best judge of temp, but i stick my finger in the charge cooler header tank after most runs and its never other than luke warm, like a cup of tea u've left on the side for too long,lol
altho i never checked it after the strip run
i'll get hold of a temp gauge etc for the air and water in the cooler and see
cheers lads
Ben
before you do anything you really want to get out with some wideband to see what's happening in 4th.
Rob@Backyardracing
18-01-2009, 13:25
If your ever up my way feel free to go for a blast with my WB..
might sound stupid but what about something like a split dump valve diaphgram leaking more boost under load in higher gear?
before you do anything you really want to get out with some wideband to see what's happening in 4th.
it ran fine on rr in 4th, fuelling well within safe zone, but am guessin loading would be totally different in real world conditions?
cheers rob, may just take u up on that offer once the cars mot'd,etc and back on the road
THE MASTER
19-01-2009, 03:03
it ran fine on rr in 4th, fuelling well within safe zone, but am guessin loading would be totally different in real world conditions?
cheers rob, may just take u up on that offer once the cars mot'd,etc and back on the road
listen to scoff no RR has a fan to produce a 100mph wind ;)
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