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buy or build race motor for my 98 c70?

How to go faster, stop quicker, and turn harder. Chips, exhaust, larger turbos, bigger/slotted/drilled rotors, high performance brake pads, manual boost controllers, performance shocks/struts/springs, airbox mods and more! Also discussion on HID and Xenon lights, aftermarket foglights and other exterior lighting.
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kcodyjr
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Re: buy or build race motor for my 98 c70?

Post by kcodyjr » Thu Jan 09, 2014 6:20 pm

You're only going to get so far and no farther. There's a limit to how much contact patch you can create defined by the wheel wells and brake hardware, and a limit to how much traction any tire can achieve defined by the laws of physics.
1997 850 GLT sedan, 152K and WHOOHOO!
RIP 1996 850 wagon, 201K, hit by a runaway 4-wheeler
RIP 1996 850 GLT sedan 5spd, 260K, rearended someone
RIP 1986 245 boring, 200K, rusted beyond inspectability
RIP 1981 242 turbo 5spd, 300K, serious teenage crash

jblackburn
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Re: buy or build race motor for my 98 c70?

Post by jblackburn » Thu Jan 09, 2014 7:20 pm

kcodyjr wrote:You're only going to get so far and no farther. There's a limit to how much contact patch you can create defined by the wheel wells and brake hardware, and a limit to how much traction any tire can achieve defined by the laws of physics.
In addition to this, much wider/taller tires just won't fit this car. The wheel wells are small.

And then you're still stuck with FWD. You can put down the power (to the range of 270-300 hp) or you can steer, but you can't do both at the same time - you end up with huge amounts of tire squeal and epic understeer. On a road course, you may be able to keep up with a V6 RWD...until a corner. Then better weight distribution and physics is in the RWD's favor.

These cars are fantastically quick semi-luxury sedans for their time period, but a true sports car they were not.

I would encourage watching some YouTube clips of a high HP FWD. Something like a 300 HP V8 Chevy Impala SS FWD come to mind, though there are some crazy videos of Volvos out there too. Great V8 engine...FWD piece of crap car that was useless at doing anything but spinning the front tires. I'm completely surprised it even made it into production.
'98 S70 T5
2016 Chevy Cruze Premier


A learning experience is one of those things that says, "You know that thing you just did? Don't do that."

mercuic: Long live the tractor motor!

socompsp
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Re: buy or build race motor for my 98 c70?

Post by socompsp » Fri Jan 10, 2014 9:41 am

when you guys are referring to losing traction, are we speaking in terms of launch? cause i figured that all the power would come in handy while at a rolling start? i understand my c70 is no where near an ideal sports car. i just wanna stick it to him for talking crap about our volvos. how feasible would installing an awd from an 850/s70 be? i realize the c70 is wider, but how likely is it to be accomplished? i have welding skills, and since this is a passion of mine money doesnt really weigh to heavy on my mind. truth be told i wanna beat rob and his eclipse then im prolly gonna start working on modding a lotus.
RIP: My Father 10/17/13 The Spiegel Grove claims another Soul.
"We are all the sum of our choices. The fear is not of dying... it is to not have lived."
Forever loved. Never Forgotten.

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Re: buy or build race motor for my 98 c70?

Post by jblackburn » Fri Jan 10, 2014 9:45 am

The T5's have zero power from a launch anyway - stock, mine doesn't even chirp the wheels if you just floorboard it. When the turbo kicks up, the front tires will spin away at 20-30 MPH.

If you roll into it above 30, you may be alright.

Oh...the limit of the transmission (if auto) is about 300 HP too. Beyond that, boom. Make sure you upgrade the transmission cooling system with more power through it.

AWD would require changing the rear suspension, fuel tank, and transmission...more work than you probably want.
'98 S70 T5
2016 Chevy Cruze Premier


A learning experience is one of those things that says, "You know that thing you just did? Don't do that."

mercuic: Long live the tractor motor!

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kcodyjr
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Re: buy or build race motor for my 98 c70?

Post by kcodyjr » Fri Jan 10, 2014 12:08 pm

Actually, AWD might not be too hard, if you have a complete donor car. The real question is, what models would have a fuel tank that will fit into the C70.

As I read it, jblackburn, this guy might be willing and able... seems he's got a bone to pick. :)

Also, you T5 guys can eat ya hearts out. The GLT launches like a fighter off a carrier deck. Might be able to achieve that if the turbo is sized *just* right.

I think it's also an open question whether a stick or auto is proper for this application. Modern automatics shift faster and smoother than all but a pro race driver, but only if the shift points are tuned right for the amount of power coming through it. It seems the manuals can take much more. Where could he get an AWD manual transmission that'll fit? A wrecked S60R maybe?
1997 850 GLT sedan, 152K and WHOOHOO!
RIP 1996 850 wagon, 201K, hit by a runaway 4-wheeler
RIP 1996 850 GLT sedan 5spd, 260K, rearended someone
RIP 1986 245 boring, 200K, rusted beyond inspectability
RIP 1981 242 turbo 5spd, 300K, serious teenage crash

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Re: buy or build race motor for my 98 c70?

Post by socompsp » Fri Jan 10, 2014 1:10 pm

my girl has a v70glt, it does scoot off the line, but once you hit like 40mph theres no more real power. the t5 does take longer to spool, but thats cause of how the managment system is setup. if i wanted to bend my connecting rods i could get 7psi under 2k as well. anyway, if i were gonna go and do the whole awd system then i may as well strip the interior and make it a legit racecar, put a foam rubber tank where the seats would normally be. i may be ok with fwd, i know people with 700hp honda civics and they run 8's. its just a matter of cutting away some of the fender and extending the hub. im gonna toy around, 425 is modest i think, my original plan was 600, but as you pointed out i dont just want an expensive smoke machine.
RIP: My Father 10/17/13 The Spiegel Grove claims another Soul.
"We are all the sum of our choices. The fear is not of dying... it is to not have lived."
Forever loved. Never Forgotten.

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kcodyjr
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Re: buy or build race motor for my 98 c70?

Post by kcodyjr » Fri Jan 10, 2014 2:25 pm

The GLT has a 13G turbo on the 2.4L block, at 9.5:1. Keys points are:

* Tiny ass turbo relative to the size of the engine.
* Higher than normal compression for a turbo.
* Done on the NA block that lacks sleeves.

It's well established that 200 ft-lb of torque at 1600RPM is easily handled.

The power fall-off comes from the tiny turbo unable to maintain pressure at higher flow rates. A 16T turbo mated to a wider exhaust would be only slightly more balanced toward the high end. A pair of NA cams would more than make up for that.

The slower spool on the T5, although enforced by the ECM via the TCV, is more to avoid overshoot than to protect the rods at the low end. The root cause is the delayed buildup of pressure that rapidly sends the turbine flying. Less load on the turbine (smaller compressor, or larger exhaust, or both) equals less delay, which permits a snapper spool up without overshooting.

In a race, launch and follow-through are both important. Spooling up to 20psi won't help if the other guy is already halfway to the finish line, and blasting off the line won't help if the other guy goes flying by at 50.

FWIW, the 40mph mark is about when mine is shifting into 2nd, if I've got it to the floor, but I've learned it's better to back off and let it shift sooner, so the RPM is lower in the next gear. In fact, I swapped in a TCM from a 96 NA wagon, into my 97 GLT sedan. It improved mileage, acceleration in sport mode, and controllability in econ mode.

I don't see why you'd need to strip the interior to get the AWD hardware into it, unless your plan is to skip the under-chassis fuel tank entirely. I'm not sure if a "legit" race car would really address your objective, though. Your knucklehead pal might just say 'well duh, of course your race car beat my street legal car'.
1997 850 GLT sedan, 152K and WHOOHOO!
RIP 1996 850 wagon, 201K, hit by a runaway 4-wheeler
RIP 1996 850 GLT sedan 5spd, 260K, rearended someone
RIP 1986 245 boring, 200K, rusted beyond inspectability
RIP 1981 242 turbo 5spd, 300K, serious teenage crash

socompsp
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Re: buy or build race motor for my 98 c70?

Post by socompsp » Fri Jan 10, 2014 10:45 pm

yes he would most likely say something like that out of shame, but he has mentioned on more than one occasion that the volvo would NEVER beat his car. and i was being a bit sarcastic when i talked about stripping the interior lol. i think im just gonna toy with the stock motor for a bit. do some light mods and add a manual boost controller. if i want to set it to 15psi, and i put the valve between the tcv and wastegate so i dont bend the rods? or will it be fine just hooked straight in? its a conflict in my mind, i dont know if the ecu will get in the way.
RIP: My Father 10/17/13 The Spiegel Grove claims another Soul.
"We are all the sum of our choices. The fear is not of dying... it is to not have lived."
Forever loved. Never Forgotten.

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kcodyjr
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Re: buy or build race motor for my 98 c70?

Post by kcodyjr » Fri Jan 10, 2014 11:07 pm

Don't screw with an MBC. It's just going to fight the ECU, and deprive the ECU of its ability to keep the motor from blowing itself up. Just go straight for an ARD tune.

Have you done an HD TCV yet? Silicone vacuum and air hoses? Anything that removes a variable, especially an unsensed one, or that makes reality more closely match the math, will help the ECU get more out of the engine.

You might try a set of NA cams in it.

Air intakes seem to be questionable, though, the factory box is well tuned especially for the low end.
1997 850 GLT sedan, 152K and WHOOHOO!
RIP 1996 850 wagon, 201K, hit by a runaway 4-wheeler
RIP 1996 850 GLT sedan 5spd, 260K, rearended someone
RIP 1986 245 boring, 200K, rusted beyond inspectability
RIP 1981 242 turbo 5spd, 300K, serious teenage crash

socompsp
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socompsp

Re: buy or build race motor for my 98 c70?

Post by socompsp » Fri Jan 10, 2014 11:40 pm

nothing special has been done with the car yet. once my son was born it took a back seat, and has been sitting since i got my bmw. im now getting around to researching what i want to do and have a plan set in stone, then almost the whole car is coming apart and being rebuilt as best as reasonably possible.
RIP: My Father 10/17/13 The Spiegel Grove claims another Soul.
"We are all the sum of our choices. The fear is not of dying... it is to not have lived."
Forever loved. Never Forgotten.

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