Handling/drive-ability for optimistic engine options.

Handling/drive-ability for optimistic engine options.

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Discussion

rhosch

Original Poster:

23 posts

121 months

Wednesday 2nd September 2015
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Thanks Stig... saw the option from AS. Factory "approved" and kinks worked out is certainly appealing. The only reason I'd consider reinventing the wheel is because in this part of the US it is so common that labor and support is relatively cheap, and I'd likely save quite a bit of cash for a similar result. Haven't ruled that out. May settle on NA but aside from cost and complexity (only, ha!), a bit of boost seems an easier (or at least more durable) way to get there than NA tuned to the nines.

Could I tease more comments out of you about your previous GTRs and whether you felt it was hard to control traction vs your experience with turbo setups?

deadscoob

2,263 posts

259 months

Wednesday 2nd September 2015
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Is there any chopping about still required for SC engines?

Storer

5,024 posts

214 months

Wednesday 2nd September 2015
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I is worth remembering that you are buying a hobby and not just a car.

If you think about a hobby it is seldom a finished product, and the item is constantly changing. This can be the case with an Ultima. It is best not to think of it as finished, but as a work-in-progress.

With this in mind you can build the car with a 'plan' to fit FI but start with NA. Make the upgrade doable without starting again, but if you decide to stay with NA it is not an issue.

I will probably fit a mild cam upgrade at some point (more a case of testing my abilities in engineering as well as driving) but probably not because the car needs more power on the road.

If you are building for a short term ownership, then do what you want, but don't expect to get anything like what you have spent back on resale.


Paul

rhosch

Original Poster:

23 posts

121 months

Wednesday 2nd September 2015
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Definitely would plan for the long haul. I've thought about the "upgrade path" engine option. I suppose it could be build "FI ready" but that would mean lower compression and different cam profile far from optimal for a NA engine. I wonder how much base power might be made? 400 hp or so perhaps, which would probably be fine and scare me just as well. smile Would require likely repurchase of some stuff later mainly associated with pulleys, accessory mounting, and main belt, would have to pay for tuning twice, maybe some duplicated cost in engine control electronics... not the most efficient. But my biggest concern is cooling. Not sure I could or would want to properly fit intercooler and supporting pump, etc., without the charger in place, and wouldn't it be a lot harder to do on the back end?

Still an appealing option. I'm just trying to think through how it all could play out so that I don't get more of a headache later by trying to avoid one up front!

Stig

11,817 posts

283 months

Friday 4th September 2015
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rhosch said:
Thanks Stig... saw the option from AS. Factory "approved" and kinks worked out is certainly appealing. The only reason I'd consider reinventing the wheel is because in this part of the US it is so common that labor and support is relatively cheap, and I'd likely save quite a bit of cash for a similar result. Haven't ruled that out. May settle on NA but aside from cost and complexity (only, ha!), a bit of boost seems an easier (or at least more durable) way to get there than NA tuned to the nines.

Could I tease more comments out of you about your previous GTRs and whether you felt it was hard to control traction vs your experience with turbo setups?
Traction isn't an issue - plenty of rubber on the road for that at the rear, but can overwhelm the fronts a bit on turn in.

Can't comment on turbo I'm afraid as I've not had that setup in an Ultima, but were I do to so, I'd make sure it was as lag free as possible to avoid any unwelcome mid-corner surprises! Centrifugal superchargers may be the middle ground, but I preferred the 'stomp' from zero of a roots.

A bigger issue will be under canopy temperatures - it gets very toasty under there bit a supercharger, so would expect even more so with Turbos - and consequent effect on general cooling.

Making big power is one thing - making big power and it behaving whilst stuck in traffic in high ambient temperatures is quite another.

The latter gets tedious very quickly in my experience.

It's been 12 years (OMG!) since I build my first Ultima and the engine game has moved on a long way since. Ultimately (excuse the pun!), it's down to how you'd like to use it and what you'll enjoy when building/driving it. If that means mega power, trips to the strip and short journeys for high days and holidays then go for it. If however you want it to be both a wolf and a kitten, then a stock LS7 may serve you better.

Having built a track-focussed supercharged GTR and a far more road biased Can-Am, they fulfilled different desires/requirements - but the latter was definitely the more usable in either environment.

But as I said, it's down to personal choice and what you'll enjoy from the experience - both building and driving smile

Edited by Stig on Friday 4th September 14:43

rhosch

Original Poster:

23 posts

121 months

Friday 4th September 2015
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Thanks... I certainly value input that comes from experience on both sides of a question! It's hot in the southern US, and cooling may well make the choice for me.

2001ultima

234 posts

154 months

Saturday 5th September 2015
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My opinion is to go with a NA high RPM ~500-600hp engine (modified LS7 with stronger internals to sustain high RPMs) and a Bosch ECU and invest the money that would have gone into an expensive 1000 hp setup into a sequential shift transaxle. Then you are setup for further future upgrades like paddle shift, Bosch traction control, Bosch ABS. Oh, and the long front wishbones with the widest front tire possible. If time is available, possibly wait for the rumored mid-engine GM supercar to arrive, not sure what transaxle GM will use but then that could be an option with the GM ECU.


Racingroj

488 posts

162 months

Saturday 5th September 2015
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Spot on Jim. My ideal.

Storer

5,024 posts

214 months

Saturday 5th September 2015
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2001ultima said:
My opinion is to go with a NA high RPM ~500-600hp engine (modified LS7 with stronger internals to sustain high RPMs) and a Bosch ECU and invest the money that would have gone into an expensive 1000 hp setup into a sequential shift transaxle. Then you are setup for further future upgrades like paddle shift, Bosch traction control, Bosch ABS. Oh, and the long front wishbones with the widest front tire possible. If time is available, possibly wait for the rumored mid-engine GM supercar to arrive, not sure what transaxle GM will use but then that could be an option with the GM ECU.
Please tell me when you envisage holding more than 7000rpm for more than a very, very short period. An Ultima is a light car and torque creates the acceleration, so you spend more time in the torque band than at high revs. An LS engine is not a Ferrari flat plane crank engine so trying to get an LS to perform like flat plane crank is pointless.
You are not building a dragster. You would start with something very different if you were!

As said above, a sequential box or a PDK/automated shift gearbox would make the car a better track car (and probably a better road car, but not sequential).

Every prospective builder that comes here after 'big power', and builds it, is back later with issues that spoil the ownership experience. Many have 'downgraded' to lower power to get a car they can enjoy.

This is a hobby so you can do what you want, but making a car that is fun to drive is not all about high revs and big power.


Paul



2001ultima

234 posts

154 months

Sunday 6th September 2015
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Paul, Good points. I'm speaking from a One Lap of America perspective, for example, one of the tracks on the rout this year was 3.1 miles I believe. We did one practice lap and then full on for 3 more laps. I was at max RPM for pretty much the entire 3 laps and part of the practice lap. There were some very fast cars/drivers in the event. I would like to do the One Lap again and would want the dream setup described above to help be competitive. Jim

deadscoob

2,263 posts

259 months

Sunday 6th September 2015
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Something with the low down torque of an ls7 that revved to 8k would be fantastic.

Paul is right re road use though - although you could class the power delivery of these modern engines as a little "dull", there's no real step up in their power delivery which I like.
I'm of the opinion you can only enjoy the performance fully on track too, but also agree with Paul about owners going for big power then scaling back. But if that's what you want to do, then do it, you can't be rational with these things smile

andygtt

8,344 posts

263 months

Sunday 6th September 2015
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The problem with the high power cars is they often forget the basic physics and don't pay enough attention to managing them.

As a rough rule all engines convert 1/3 of the power into BHP, the other 2/3 goes to noise, vibration, heat etc. We have to keep the noise down and want to eliminate vibration therefore more heat is the main by product. This is true for FI or NA although with turbocharging you retain some of this heat in the car to drive the charger and thus have to manage that.

simple fact is a cooling system which is adequate for a 400bhp ultima simply won't and can't cope with a 600 bhp engine, you MIGHT get away with it on idle as both engines may be producing the same power at that point.... But come in from teach into the pits and expect the 600bhp To pull the temps down and it won't.... You need to upgrade the cooling to the same extent as the engine OR accept to have issues in certain circumstances.

As for the revs debate, I'm a firm believer that higher revs in a lightweight car make for a faster machine.

2001ultima

234 posts

154 months

Sunday 6th September 2015
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Right, it's all what the Ultima will be used for. Another nice engine choice for a builder that will track their Ultima would be the new Ford flat plane V8 5.2L engine, 8,250 RPM redline and 526 hp. I'm sure with headers and a few other basic modifications the hp level might be a little higher.

listen to the sounds in this video: https://www.facebook.com/caranddriver/videos/10154...







2001ultima

234 posts

154 months

Sunday 6th September 2015
quotequote all
andygtt said:
simple fact is a cooling system which is adequate for a 400bhp ultima simply won't and can't cope with a 600 bhp engine, you MIGHT get away with it on idle as both engines may be producing the same power at that point.... But come in from teach into the pits and expect the 600bhp To pull the temps down and it won't.... You need to upgrade the cooling to the same extent as the engine OR accept to have issues in certain circumstances.
I wonder if there are any cooling upgrades for the new 1000hp EVO? Possibly large radiator, bigger fans, fan shroud and front canopy enhancements to clear larger cooling hardware.

jmwram

123 posts

212 months

Sunday 6th September 2015
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listen to the sound in this video also ,old school 383 chevy on carb with cherry bom rear silencers http://1drv.ms/1M4geCy

UltimaCH

3,155 posts

188 months

Monday 7th September 2015
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2001ultima said:
Right, it's all what the Ultima will be used for. Another nice engine choice for a builder that will track their Ultima would be the new Ford flat plane V8 5.2L engine, 8,250 RPM redline and 526 hp. I'm sure with headers and a few other basic modifications the hp level might be a little higher.

listen to the sounds in this video: https://www.facebook.com/caranddriver/videos/10154...
Now that definitely sounds more modern smile

jmwram

123 posts

212 months

Monday 7th September 2015
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2001ultima said:
I wonder if there are any cooling upgrades for the new 1000hp EVO? Possibly large radiator, bigger fans, fan shroud and front canopy enhancements to clear larger cooling hardware.
The evolution has fans now fitted in front of the radiator to alow for a bigger core rad i would guess,also the fans would be a lot more powerfull more air movement,could also have an electric water pump ?,i have the moroso electric pump that works well.

chuntington101

5,733 posts

235 months

Monday 7th September 2015
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jmwram said:
2001ultima said:
I wonder if there are any cooling upgrades for the new 1000hp EVO? Possibly large radiator, bigger fans, fan shroud and front canopy enhancements to clear larger cooling hardware.
The evolution has fans now fitted in front of the radiator to alow for a bigger core rad i would guess,also the fans would be a lot more powerfull more air movement,could also have an electric water pump ?,i have the moroso electric pump that works well.
Are the fans in front for a larger core or to allow the charge cooler low temp rad to fit in front?

Also pusher fans generally don't move as much air as pullers.

My guess is there is very little difference in radiators. Would the factory really have the recourse to develop a new radiator for 1 engine configuration?

You probably aren't going to be using the 1000bhp for much of the time! So the stock cooling system may have sufficient capacity to cope with the increased load when you are on it.

jmwram

123 posts

212 months

Monday 7th September 2015
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i think the intercooler rads are each side of the rad air intake [small grills] ,radtec would make a rad with a bigger core for not much more money,i know them quite well and there always developing rads and intercoolers for small companys so not to expensive also mainly in alloy.i have just upgraded to better flow fans 1160 cfm each and only 10" thats about + 1/3 more airflow each than was previously fitted and works a lot better .

V8Dom

3,546 posts

201 months

Monday 7th September 2015
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jmwram said:
listen to the sound in this video also ,old school 383 chevy on carb with cherry bom rear silencers http://1drv.ms/1M4geCy
bottom s at Shelsley walsh.. not alot of space each side is there,,hahahha