RWD vs. FWD: A Personal Experiment/Showdown

[EricF]

I have two Volvos, one is a front-wheel-drive 850 turbo from 1995, the other is a rear-wheel-drive 240 turbo from 1984. They are competing to reach 13 second ETs, and to reach 105+ mph trap speeds.. Here are the two contestants:

---------------------------------------
Current Standings:
850 Turbo: 14.5 at 105
240 Turbo: 14.0 at 100.2
---------------------------------------

FWD-- The 850 Turbo:
Since getting the car, I've:
-Returned to stock injector size
-Increased fuel pressure
-Removed S-AFC
-Increased boost a little
-Replaced walbro pump with stock unit, fuel pressure stability at higher boost levels fixed
-Fixed the Aquamist (in a ghetto but reliable and cool way.. 240 idle switch welded on as a WOT switch that grounds the aquamist at WOT)

This video was taken with a little shorter tires, ~70 degrees ambient, ~17 psi, no aquamist but the tuned ECU and stock injectors without the S-AFC. It went 14.7 at 99.5 or so on a perfect 1/4 mile run set up in this manner (it cannot get off the line on account of its lack of bottom end.. cam timing testing is still underway)


Here it is with the aquamist, lower ambient (~55 degrees F), and 16ish psi boost.


I also reset the ECU after I got the aquamist running, so there shouldn't be any stored timing pull algorithms or anything like that.

Aquamist is the 1S system, with a 0.5mm nozzle, right before the throttle body. There is a wiring short inside the pump, so the hobbes switch does nothing anymore.. Once the ECU sees power, coil (+), and ground, it starts injecting. So I have a WOT switch on the throttle wheel assembly that grounds the aquamist at WOT. It's not perfect, but it beats opening up an extraordinarily complex pump to fault trace: http://www.aquamist.co.uk/cp/sys1/techsys1/pump.html

For those unfamiliar, this is the 850 that replaced my T-boned platinum 850 turbo. I took a one-way ticket to Buffalo NY after buying a sight-unseen non-running 850 turbo of a friend of mine with whom I'd been chatting about the car for years. It had a wiring problem and sat non-running for about 2 years. I drove it back after finding the problem (some 1200 miles), and have been trying to get it back into shape ever since then.

It has:
Turbonetics ceramic ball bearing T3/T04E (54 trim, stage 3 turbine wheel)
HKS external wastegate off divorced downpipe flange, controlled by Apexi AVC-R
3" SS downpipe, high flow cat, and 2.5" SS BSR cat-back with two mufflers
Aeromotive adjustable fuel pressure regulator
Aquamist 1S system
ECU from our friend Janne in Sweden (the previous owner of this car is the person who first introduced me to Janne years ago)
KW V2 full coilover suspension
IPD swaybars

I am piecing a manual conversion together for the car, I think with R compound tires and good brake pads, it would be a demon on a track with the manual. KW coilovers are really incredible.

I'll try to get some videos at low ambient temperature, because it seems under ~40 degrees the boost is harder to control and sits around 18-19 without touching the boost controller. So it's of course faster at those levels.

Anyway, looks like the aquamist makes it a little more than a second faster from 25-80 mph, so that's kind of cool. And I suspect the traps up over 100 now too.




Its three timeslips to its name are
14.8x at 94.5 with a 2.3 60 foot (without changing anything, 16 psi on the big injectors, S-AFC, walbro pump, fuel pressure ~stock)
14.7x at 99.5 with a 2.4 60 foot, setup as seen in first video
14.7x at 99.7 with a 2.5 60 foot, setup as seen in first video but with 19 psi and hung it off the limiter gate-shifting out of first.. indicates possible trap of maybe 101ish?

All track times were done with the car fully loaded up on the stall, launching around 4-5 psi with no wheelspin at 2500 rpm..

-------------------------------------------------------------------------------------------------------------------------------------------------


RWD-- The 240 Turbo

I acquired this car in trade from Jeremy (coondog240) for the pristine 244 that I got from Kenny (and improved upon, as did Jeremy, car is currently for sale from Jeremy btw ). Since acquiring it, I have:
-Converted from K-jet to megasquirt with EFI intake and R injectors
-Converted from 60/63 T3 with Volvo w/g housing to TD04HL-19T with ported conical outlet housing
-Increased ignition timing advance a ton (runs base timing of 22-24 degrees BTDC)

Just basically done a lot of tuning and started taking the foundation that Jeremy built closer to its potential (do we see a trend here? buy cars with good foundations and doing finishing work).

Its current setup:
-freshened B21FT
-405 BCP head, heavily ported, finely polished exhaust side and chambers, stock valves, 5-angle valve job, shaved a bit, copper sprayed HG and old style bolts
-TD04HL-19T with ported conical outlet housing, running 23-26 psi fading to 19ish by redline
-heavily ported 90+ turbo manifold
-EFI intake manifold with R injectors controlled by 8x8 Megasquirt fuel-only
Stock intercooled B21FT mechanical distributor, 22-24 degrees initial advance
-Precision Intercooler mounted behind grille
-Full 3" exhaust with one muffler
-HKS SSQV blowoff valve
-Stock M46, flat flywheel and stock non-intercooled turbo clutch and pp (8.5" disc)
-4.10 1030 rear end, open
-old style Falken Azenis 205/50/15s on virgos
-Bilstein HD's and cut EST springs
-Momo 1000 Lakes Evo carbon/kevlar seat

Here's the one poor video I have of it..


I think it's faster since then though. And it wasn't stupid-shifted into second gear like usual. Its best timeslip is seen here:


Times that night ranged from 14.0-14.2, I think 7 in total. Traps were all high 98s to I think 101? 60 foot times ranged from 2.2 to 2.4, and seemed to have little bearing on the ET (though there was correlation with the 1/8 mile ET). The only noticeable difference between any of the runs that was seen on the slips was my lowest ET (14.2x) and highest trap on a run where I slow-shifted into second to keep from spinning. It's a very fast and fun and consistent car, along with being dead reliable although not very comfort-oriented (no blower motor, no radio, no power steering or AC).



And my desktop background:


The blue car also has a T5 transmission, modified M46 bellhousing, adapter plate and driveshaft front half sitting in the trunk weighing it down currently


So, let's hear some commentary!

[242Bleek]

Very cool eric, How in the hell do you get a M46 to live up to 26 psi from anything, let alone a non IC stock clutch I think you forgot to mention the 10 kilo's of magic volvo pixie dust in your trunk as well Also, what map sensor are you running on your MS to make it digest 26psi?

[EricF]

Originally Posted by 242Bleek

Very cool eric, How in the hell do you get a M46 to live up to 26 psi from anything, let alone a non IC stock clutch I think you forgot to mention the 10 kilo's of magic volvo pixie dust in your trunk as well Also, what map sensor are you running on your MS to make it digest 26psi?

I drive it like it's stolen too... I mean, every mile it's driven is more or less WOT and speed-shifted. It's the ultimate fun car. Stock MAP sensor (2.5 bar), just have very rich top bins in the midrange (it's only another 4 psi, on this setup I don't think there is much difference between 22 and 26 psi, it fades pretty quickly too). Once I put the angle-outlet housing on the car, I might have to keep boost in the MAP sensors range though as the VE goes up a bit.

[DecalServiceBrett]

convert to msNs

then lets talk

[EricF]

Better picture of the 850,



Taken today after I thawed out the nozzle at the self serve wash place and rinsed it off.

[coondog240]

ooh I'm gonna make one of these shootouts too. The 240 does seem a bit nastier since the incident, I lowered the boost to 17-18 and it's good. The 850 is coming right along, so we'll see.

[JohnMc]

240 will hit the ET target first, the 850 will hit the trap speed first?

RWD dig gets it the better ET even with less HP.
FWD gets the HP easier because 20V >>>> 8V.

[EricF]

Originally Posted by JohnMc

240 will hit the ET target first, the 850 will hit the trap speed first?

RWD dig gets it the better ET even with less HP.
FWD gets the HP easier because 20V >>>> 8V.

This is kind of what I am thinking, although I think the hardware setup on both cars is capable of hitting the trap speed so it will be interesting (well, once the 19T has an angle-outlet housing).

It also depends on what I do over Christmas break. Either the 240 gets the T5 and the angle-outlet housing plus some tuning.. Or the 850 gets a manual transmission and some tuning. If the 850 gets the attention, it should get the trap by the end of the year, if the 240 gets the attention it should get the ET and the trap by the end of the year I think the 240 is just a repeat trip to the track away from 13s, but it's also in south Florida some 800 miles away from me..

Jeremy, I want to see that 244 with the exhaust manifold ported like the blue one's is, and a 19T straight-outlet turbo in it.. And your 850 with good tuning. I wonder who would have the lowest combined ET and highest combined trapspeed between us

[EricF]

The 850's air/fuel ratios are at a fatty 10.0-10.5:1 before 5000, and lean out a tad up to about 11.5:1 before the shift. This, at 16 psi (well, 16-17 psi according to the Autometer electronic boost gauge, 1.2-1.25 bar according to the AVC-R). I may back fuel pressure down a little, but first I want to datalog on some cold days when the boost is more like 20 psi.

BTW, Autometer Ultra Lite wideband air/fuel gauge kit is awesome. It has a WOT switch output for a peak lean WOT recall function, datalog output for EMS (will be nice when the 244 borrows it), and the price including a Bosch LSU sensor and 8 foot wiring harness is around 230-240 shipped on fleabay.

After both of my rear upper shock mounts in the 850 ripping the other day, it's back on the road with Bilstein HD's in the rear with the KW springs... The KW shocks will need to go out for rebuild time. Might take another video sometime to show the air/fuel, boost and fuel pressure cluster as the car accelerates

[EricF]

Going to the track today... Ambient should be around 60, full weight 850 with a good amount of gas in the tank. Boost should be 17ish psi, might turn it up a little higher. Any guesses?

[maxman142001]

times, times, times?!?

[EricF]

Originally Posted by maxman142001

times, times, times?!?

Ugh. 15.0 at 96, 15.3 at 95, 15.6 at 93... I was having some difficulties with the AVC-R. For some reason this car and this tune just doesn't like starting from a stop. By the time I was almost home, the car started pulling well again, and now it's more or less back to normal. For this reason, I'll be focusing on the blue car over the holidays

[linuxman51]

you need to ditch the avc-R and get a normal ebc/mbc.

[Nick]

my favorite pic of that blue car

[SteveP]

Love the 244... is that a Volvo front splitter?

[MikeHardy]

don't like cold air on ether car eh?

getting that filter extended down to near the front on the 850 might help a bit

[DaButcher]

man, that 240t IC is TINY!
You can fit a huge ic in the frontal area, like 12" tall and 24" wide.

[EricF]

Originally Posted by ravennexus

don't like cold air on ether car eh?

getting that filter extended down to near the front on the 850 might help a bit

Agreed... I will do that when I mess with piping and do a front mount intercooler on the car

Originally Posted by DaButcher

man, that 240t IC is TINY!
You can fit a huge ic in the frontal area, like 12" tall and 24" wide.

Also agreed, but it is a high-flowing high-quality Precision IC core, and with boost levels of ~20 psi the intake temps rarely exceed ambient by more than a degree or two

[boostin'xr4]

Originally Posted by Nick

my favorite pic of that blue car

That's now my desktop background.
...and motivation for me to get the new FMIC hooked up.

[EricF]

So, although it's behind the boat in terms of time priority, I think the blue car will come apart this summer to take care of some hanging issues and get some updates. Plans:
-Install the T5 in the trunk, with stock PP, cable clutch engagement, clutchnet 4-puck sprung hub disc on a stock resurfaced flat flywheel. Driveshaft to be determined after it's mocked up..
-Install the angle-outlet turbine housing in the car, rebuild the 19T with a new turbine wheel (bent a fin taking the conical housing out because I'm all thumbs). Will be accompanied most likely by a Mike downpipe with a v-band disconnect right after the turbine outlet-- for future possible use of bigger turbo and ATP ultimate internal gate
-Replace the horrendously damaged steering rack, this time with power steering. Possibly A/C but still up in the air on that.
-New front seals on the engine, have a little oil caking around there now
-Megasquirt spark control, probably just with an ignition module and LH 2.2 distributor.. Nothing fancy.

I think that hardware setup will carry the car to my fastest-ever 1/4 mile times, possibly best traps too... Depending on how it holds up, and the power numbers it produces, I may put the fancy turbo from the 850 on afterwards.

As an 850 update, the USB turbo tuner software is currently on order. I will have full spark control and full fuel control with the stock EMS. I think with a manual boost controller and full tuning capability, the car should be catapulted forward in performance.

It is now at 59 pounds base fuel pressure, as with the colder weather the boost has been climbing to ~20 psi... AFRs lean out to about 12.5 by 6000 RPM from the mid-low 11s. When the USB tuner software is installed, I'll probably put the green injectors from the blue car in, and get some bigger injectors for the blue car.

This is just an update as to what's been going on (aka not much). I think the 850 might reach the trap and ET targets before the blue car simply because the blue car is off the road now. But I also think once the blue car is back and tuned, it will eclipse the 850 in both trap and ET...

More later

[EricF]

Still without any real times... But here is the 850's latest youtube appearance. ~17-18 psi, and low (sub-40F) ambient temps.


I still have inconsistent WOT AFRs in the car, even with some nice Volvo 'blue' injectors (350cc/min at 3bar, nice multi-nozzle spray pattern, found in 99+ T5 Volvos). Today I heard a couple of very light and very isolated detonation events at a couple points when the AFRs mysteriously leaned a bit. It's a lot different than in redblocks. You hear one knock and it stops because the ECU has knocked back timing immediately thereafter Still unnerving.

The boat is still on top of the list, but next week I'll be back down south and will be near the blue car again, so it's anyone's guess. I may get the car going with the M46 and old clutch still in it, just to see what the angle-outlet housing performs like. Given the rest of the HW setup I expect a drastic change in character.

I am also house-shopping, so as soon as I have a house with garage, the 244 with get some jackstand time and have its issues addressed fully. It may well win this battle yet

[boostin'xr4]

Your 244 is still my favorite.
The color combo is great. :D

[EricF]

Not so insignificant things have been ordered for the 850....

Meanwhile the 244's parts (transmission, turbine housing, LH2.2 distributor etc) continue to reside in trunks only.

[Alex Buchka]

You should put those not so insignificant things in the 240 instead along with one of those newfangled aluminum engines.

[EricF]

Originally Posted by Alex Buchka

You should put those not so insignificant things in the 240 instead along with one of those newfangled aluminum engines.

Not impossible in the future at some point... But right now I think the M56 and all the 850-specific shifter and **** goes into the 850. The tune in the car is more or less dangerous as it sits, with AFRs ranging from 10s to 14s at WOT with no real rhyme or reason. The 240 will get its time, and a whiteblock is not out of the question

That has been my ultimate goal for some years now. The T5 trans with redblock takes some of the fabrication work out of an eventual whiteblock swap, and the VEMS setup in the 850 makes for an easily duplicated such setup in the 244. I have considered these things