front end downforce

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mrtwo-red
Posts: 58
Joined: Mon Nov 06, 2017 5:08 pm

front end downforce

Post by mrtwo-red »

as title at speed (on closed road) front end goes really light at 85 clicks . as anybody done any mods , like bonnet vent aka nsx r to deflect air over front of bonnet
SonicSW20
Posts: 3681
Joined: Mon Nov 29, 2010 7:54 pm

Re: front end downforce

Post by SonicSW20 »

Have you got all your undertrays?

Fitting the Rev 5 'speed flaps' helps.
gavsdavs
Posts: 702
Joined: Thu Nov 15, 2012 2:31 pm
Location: saahfeeeeastlaandun

Re: front end downforce

Post by gavsdavs »

Light at 85 sounds like something is wrong. rev 5 speed flaps help with stability but you should be fine well into 3 figures on the stock body.
markstevieandmads
Posts: 2025
Joined: Mon Aug 05, 2013 8:18 pm
Location: Swindon, Wilts

Re: front end downforce

Post by markstevieandmads »

Is your power steering switching off at the correct point?
CalMac
Posts: 1747
Joined: Mon Jan 14, 2013 7:08 pm
Location: Northampton

Re: front end downforce

Post by CalMac »

Struggled with this for ages. After a LOT of experimentation with fabricating splitters, canards, bonnet vents etc. the biggest difference came from getting the geometry sorted! And finally finding a suspension combination which I get on with.

The trick is getting the front end ever so slightly lower than the rear, and minimalising front lip/bumper clearance. Front splitter definitely works but will scrape all the time which is very annoying (at 80+(kmh..) I actually noticed that it would be scraping almost continuously on the motorway, despite there being about 30mm ground clearance when parked. So proven results of downforce!
pbmr2
Posts: 929
Joined: Fri Jun 18, 2010 12:49 pm

Re: front end downforce

Post by pbmr2 »

markstevieandmads wrote:Is your power steering switching off at the correct point?


This ^

Is the car an import?
Some of the speed converters don't turn off the power steering when it should so the handling feels very light and all over the place at speed. Had this issue on my old rev2 glimited.
rainen
Posts: 34
Joined: Sun May 08, 2011 1:43 pm

Re: front end downforce

Post by rainen »

This is a V6 conversion. The Camry ECU has no control over the power steering and therefore it’s on all of the time. For the record this car has all of its under trays. As the builder of this conversion the car had no problems with front end at three digits with coil overs and 17” wheels. The car was sold with standard suspension and Rev 5 wheels so performance is going to be somewhat different with the heavier engine in the back.
gavsdavs
Posts: 702
Joined: Thu Nov 15, 2012 2:31 pm
Location: saahfeeeeastlaandun

Re: front end downforce

Post by gavsdavs »

rainen wrote:......performance is going to be somewhat different with the heavier engine in the back.

You do realise that the engine is IN FRONT OF the rear wheels ? And PFWPF says that means the 'heavier engine' works in your favour if you want to use that argument ?

I believe the steering ECU is speed related - does your speedometer work ?

9 times out of 10, 'light front end' behaviour is down to tyres, bushes, alignment or some other defect, not aerodynamics or weight.
rev3gtturbo
Posts: 424
Joined: Mon Jan 30, 2006 10:31 pm

Re: front end downforce

Post by rev3gtturbo »

mine goes light on the front end when the tyres get down to 2-2.5mm.
rainen
Posts: 34
Joined: Sun May 08, 2011 1:43 pm

Re: front end downforce

Post by rainen »

OK lets just state the facts about the car then members can offer informed suggestions:

Full set of under-trays
New power flex bushes on all suspension components
Lower ball joints all new as are track rod ends
Wheel alignment last done with 17" wheels just before sale
Speedo works fine

However prior to sale:

BC Coilovers replaced with standard rev 5 suspension
17" wheels replaced with standard rev 5 wheels
MOT warning on front offside Tyre (inner edge worn on other car)
gavsdavs
Posts: 702
Joined: Thu Nov 15, 2012 2:31 pm
Location: saahfeeeeastlaandun

Re: front end downforce

Post by gavsdavs »

rainen wrote:
BC Coilovers replaced with standard rev 5 suspension

New or old "rev 5 suspension" ? What's the history of that kit.

rainen wrote:
17" wheels replaced with standard rev 5 wheels

Should improve the ride, but make no real difference.

rainen wrote:
MOT warning on front offside Tyre (inner edge worn on other car)

Might make it feel a bit vaguey and understeery but not light.
rainen
Posts: 34
Joined: Sun May 08, 2011 1:43 pm

Re: front end downforce

Post by rainen »

The Rev 5 suspension is 20 years old having covered 102k miles.
mr2garageswindon
Posts: 282
Joined: Wed Oct 15, 2014 3:02 pm

Re: front end downforce

Post by mr2garageswindon »

Well overdue a refresh then.... Yellow Billies time I recon.
CalMac
Posts: 1747
Joined: Mon Jan 14, 2013 7:08 pm
Location: Northampton

Re: front end downforce

Post by CalMac »

Was the geometry set up again having reverted to the Rev 5 suspension?
rainen
Posts: 34
Joined: Sun May 08, 2011 1:43 pm

Re: front end downforce

Post by rainen »

No. The buyer was made aware of that at time of sale.
pbmr2
Posts: 929
Joined: Fri Jun 18, 2010 12:49 pm

Re: front end downforce

Post by pbmr2 »

The post about the steering never going off, this is the issue I suspect. The steering control only needs a speedo input from the dials, it sorts the rest out if there are no faults.

Is the car an import? Only asking as some speed converters also mess with the steering due to hiding the real road speed from the steering ecu, so the ecu never turns off the assist.

The alignment does sound like it needs doing again, not mega money and should sort tyre wear and help handling. though prob won't fix the front float in this case.

should all be simple fixes :D
rainen
Posts: 34
Joined: Sun May 08, 2011 1:43 pm

Re: front end downforce

Post by rainen »

Now that's an interesting post. Yes it is an import and yes there is a speed converter sitting behind the instrument cluster. I did review the wiring diagram to check how the Power Steering ECU interfaced to the cars speed. I've got a picture of what it is and how its wired behind the cluster if the new owner needs it (unable to figure out how to post pictures on this forum!). I never really had a major issue with the car but also never thought that the speed convertor could interfere with the operation of the Power Steering ECU. I've learned something new today...................
mrtwo-red
Posts: 58
Joined: Mon Nov 06, 2017 5:08 pm

Re: front end downforce

Post by mrtwo-red »

thanks for all the replies very happy with the car as rainen said susp is 20yrs old so am going down the coilover route i had a set of hsd on my gs430 sport which transformed the car ( plus being set up by centre gravity -porcshe susp specialist ) so looking at them at moment ,or do members have another set they can recommend .. i want fully adj to soften ride up after lowered .. cheers
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