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Motor for an Ultima

General engine tech -- Drag Racing to Circle Track

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Motor for an Ultima

Post by j-rho » Sat Aug 01, 2020 4:43 pm

Hi Speed Talk!

I recently ordered an Ultima RS (a small, British, enclosed Le-Mans style car) to use for a mix of road trips and hot laps on the road course. It won't be here for at least 6-7 months; in the meantime, have to decide how to power it.

The motor is the heart of the car and I'd like to put together something really special - would love this group's input on ideas.

Ultimas have been using GM V8s for decades, most recently LS and LT variants. Others have fit in European V10s and I think even small BMW V12s. The GM stuff is by far the most popular though - in addition to their size and weight benefits, adapters to affix them to mid-engine transaxles are plentiful.

I'd like to stay away from forced induction and anything finicky or high maintenance. Already have a '67 Camaro with a hot 302 for when I feel like dealing with a carburetor and SBC oil leaks :)

I intend to run Motec engine management with traction control, where it would be easy to switch between 91, 100, and 109 octane tunes depending on fuel available. The car will be used primarily at One Lap of America - an event where you run a bunch road course laps and then drive 5-600 highway miles 7 days in a row all over the country, with some drag racing thrown in. The motor needs to do this over and over and over and not break a sweat.

Power target is 750-800hp crank on 100 octane. For road course driveability, would like as flat as possible a torque curve from ~4000rpm to redline.

Some candidates:
A fully built 7-ish liter LS from Katech, Lingenfelter, Texas Speed, or the like (easy button)
Mercury Racing's SB4 (LS7 block with quad-cam heads, reliable 8000rpm redline)
Dodge Viper V10 with heads/cam (I ran Vipers for years and am fond of how understressed they are)

Had looked at an SB2 but maybe doesn't meet the "finicky" bar. The motor needs to idle in traffic and allow the car to get going smoothly from a stop.

There's more height available to fit a taller intake than you could in a front-engined car, which maybe helps.

Thank you in advance for your thoughts!

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Re: Motor for an Ultima

Post by pdq67 » Sat Aug 01, 2020 5:01 pm

IF it will fit, no more than an old-school Chevy 427 L88 engine with no more than headers on it. Should be like 540 or so hp(??).

Will be solid as a rock!!

I can see, "Can Am", written all over it.

Sure its old-school, BUT it will RUN!

If weight is a problem and you have money, A ZL-1 spec'ed as an L-88 all aluminum one...


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Dave Koehler
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Re: Motor for an Ultima

Post by Dave Koehler » Sat Aug 01, 2020 5:12 pm

That's a neat looking piece.
LS is the prudent route.
The V10 is the cool factor route.
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Re: Motor for an Ultima

Post by Paul Kane » Sat Aug 01, 2020 5:50 pm

Are you firm on the engine being non-forced induction? I have a 1200 HP Twin Turbo World Record Setting Quad 4 that will be listed shortly.


You could detune it with some tiny turbos for your "reliable" 800 HP. Of course your desired torque curve will certainly be there. And like your car, it is made with British (Cosworth) components. And hey, talk about power-to-weight ratio. :)

Or if you'd prefer we have a 32-Valve Olds Aurora Indy Car engine sittign at the back of the shop that will be put up for sale shortly as well.

Either would be very unique.
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Re: Motor for an Ultima

Post by rebelyell » Sat Aug 01, 2020 6:02 pm

RY45 variants

turbo camino
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Re: Motor for an Ultima

Post by turbo camino » Sat Aug 01, 2020 8:07 pm

Mercedes M119.

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Re: Motor for an Ultima

Post by ptuomov » Sun Aug 02, 2020 2:45 am

Wouldn’t you want to get an engine that is dry sumped or semi dry sumped in its original application?

Like Porsche Cayenne engine. Would that fit, either in factory turbo version or the normally aspirated version? The turbo version should get one to a reputable power levels with minor tweaks. But that’s just one dry sumped or semi dry sumped option.
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Re: Motor for an Ultima

Post by englertracing » Sun Aug 02, 2020 2:55 am

Incase you didn't know what an ry45 is....

I'm personally fond of twin screws
How about a pair of Whipples on an aluminum LS?
The torque and throttle response are better in every way.

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Re: Motor for an Ultima

Post by Bwh998 » Sun Aug 02, 2020 4:51 am

96 kg. 520hp @ 10,000 rpm, naturally aspirated.


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