Elingj, WELCOME to the forum! Enjoy the ride and company.


Richard Migliori

 

Wow, that sounds like its going to be a show car build that will just rip up the street. Can't wait to see your progress!

I haven't placed the order yet but I'll also be a first time builder, I can share your excitement. Congrats on making the jump! So 6-7 weeks turn-around time from FFR?

If you're not utilizing the engine or brakes, does it make sense to go with a donor for you?

Aman

 

I want to watch this build, you are where I was two years ago with the Roadster, now I want a GTM too. Nice.

 

Aman, I'm going with a pallet so I can ask them to omit the engine, engine harness, computer, fly by wire pedal, rotors, and calipers to avoid duplication of parts and save a tiny bit of money.

 

Sounds like a great build! Look forward to following your build... My only suggestion, is to re-think your transaxle. I dont think a G50-03 will survive behind that motor. Consider a G50-50 or GT2-3 box... or a few other non porsche transaxle options.

David

 

The G50-50 is no longer supported by FFR because it is of the 1987 to 1989 case design. In this same vein, the G50-52 is the next best. After that, the Gt2-3 boxes

 

David,

I have been researching the transaxle matter for the past two months asking questions at different forums. I finally settled on the G50/03 because the guys at Ultima have been using the stock G50/03 on their 640hp Ultima and 720hp Ultima without any problems.

Here's some video of them testing and punishing the transaxle:

http://netshow.inetc.net/ultimasports/ultima06.wmv
http://netshow.inetc.net/ultimasports/ultima05.wmv

I figure since the Ultima GTR and the Factory Five GTM are about the weight and I will be using roughly the same type of tires I should be safe. I hope.

 

Traction is minimal in these videos. Wet ground?
Car weighs in at 18-2100Lbs from what I have heard.
When traction does occur use a week material for the axle so that is your fusible link.

 

Sweet

Keep me posted. I also want to build a 700hp GTM using one of the new LSX crate motors. I plan on starting later this year, so I am in the early planning stages... first time builder also

 

Sounds like a fun build... I would steer clear of the titanium valves for anything but straight competition use - the stems and seats will not stand up for the long haul... On a 500 mile race motor, they are pretty screwed up by the time it's done. Just my past experience..

 

Thank you for the warm welcome. I also value and appreciate all of your feedback.

Big-Foot: Let me check on the titanium intake valves. I know the exhaust valves are stainless steel but let me see why LME has chosen to use titanium for the intake. Thanks for pointing this out.

 

Engine

I am not familiar with the LS engine builds, will this be naturally aspirated? If it will be a street motor I am curious if you considered Turbos or Supercharging and what your decision process was. (Again, I do not know if it is one or the other)


Sounds fun, that's for sure.

 

I agree with David

Hay there,

Congratulations on your project. I too am excited for you.

I just wanted to put in my 02 cents regarding your transaxle selection. For the amount of HP and Torque that the LS7 puts out, I would strongly recommend that you go toward a stronger transaxle. A G50/50 or a G50/52 would work well for this application.

If you are content that the G50/03 will do the trick, make sure that you strengthen this gearbox in every way possible. It was not designed to handle torque over about 600 ft/lbs.

I understand that you due to the fact that you saw someone messing around with the Ultima that you think that it will work, but consider what he was actually doing, the wheels were spinning quite a bit. This is not putting too much stress on the transaxle at this point. The stress is when you do not have wheel spin, which usually is the goal.

Now if you stengthen the gearbox with Cryogenic stress relief and REM micropolish, as well as adding a billet side plate, and cooling system, then I agree that you might well be alright. However If I am correct in my calculations, you might well do with a G50/52 for roughly the same cost, if not less.

To give you an idea on what I am talking about cost for your G50/03, unless you are an extremely lucky buyer, with all that I am talking about would far exceed the 11,000 dollar mark.

I have have G50/52 with LSD and Side Plate that I have listed here for $10,800.

I am not trying to take business away from anyone, here, and I hope that no one here thinks that this is the case, I just want everyone to know that when you get over the 600 HP mark there are things that need to be done to the G50/03 to make it handle more HP and Torque without damaging the unit.

In some cases it is better to go to another option, rather then spend that kind of money. The other nice thing about the G50/52 is that it is a 6-speed rather then a 5 speed.

Just my opinion on this and I would certainly like to hear from others on this one. I always want to know if what my gut is telling me actually equates to the real world. The GTM afterall is just a bit different from both Ultimas and Porsche cars.

Thanks all

Erik Johnson
Carquip Sales
(303) 443-1343 ext 2 work
(720) 980-9407 cell

PS David this may be a really good option for your next build, as well.

 

All the LS7 heads have Titanium intake valves. The thing to watch is the Intake rocker geometry - they have been known to fail (pushing the trunuien
(sp?) out losing all the needle bearings in the motor.)

Also I know LME put's out some good motors, but they have also put out several motors that have failed after a couple of miles.
I would ask them who is assembling the short block, If there getting Erik at HK enterprise to do it then it will be done right.

Just looking out for ya.

 

Interesting about the Ti valves.. They must be doing something different with the stems, ends and seats from the Del West or Ferrea valves we've used in the LM engines.. You had to use lash caps on them even with hydraulic cams. The stems would wear quickly as well.. Seat wear was more of an issue with those engines that were run over 9,000 RPM.. They had to have a lot stronger springs..

The LS7 is an impressive engine even in stock form. Interesting article:

http://www.popularhotrodding.com/tech/0504phr_chevy_ls7_engine_review/index.html

 

700 hp in a GTM.............How does that song go again?,.................I'm going home in a bodybag, do-dah, do-dah, I'm going home in a bodybag, oh do-dah day..........

 

i was looking at this
http://www.ffcars.com/forums/showthread.php?t=178698
and i too think the transaxle will die with that to it would the gt40 transaxle be better ?

 

Gary: Thanks for the vote of confidence.

Big-Foot: Here's what LME said about the titanium intake valves (similar to what 98Aggie said): "The titanium intake valves are not a problem. As long as they have the proper coating on them they will last a long time. The factory LS7 heads come with titanium valves from the factory. GM will not build something that they do not feel will make their warranty. GM had a couple of years and many dollars in testing the LS7. I would not hesitate to use the titanium valve in your engine. We have actually seen problems with folks trying to use a stainless 2.200" valve in an LS7 head. The problem is due to the weight of the valve. The hyd. roller springs will not handle the weight with the lobe profiles of a performance camshaft."

98Aggie: I was at the UCLA/A&M basketball game during March Madness. Most impressed by the cheerleading team...but that's off topic. The Rocker arms will be LS7 intake and exhaust rocker arms w/Harland Sharp trunion modification to resolve the problem you mentioned. Also thank you for the tip about Erik at HK doing the build.

fostereast: This will be a naturally aspirated engine. My goal with this engine is basically to have my cake and eat it too. I wanted it to start right away without a lot of cranking, I wanted a smooth idle, I wanted monster power at my fingertips, and I wanted all of this with reliability without making the engine bay too hot. I explored supercharging but it looked like the engine bay does not have enough room for it unless you do some cutting and other creative mods. Turbos were out for me b/c of heat which may degrade the reliability of the rest of the parts in the engine bay.

Transaxle: I am certainly concerned about the viability of a G50/03 or G50/05 for this set up. I share the concerns with the rest of the group here. Then I see these videos:

Standard G50/03 running 9.941 at 143mph
http://netshow.inetc.net/ultimasports/quartermile2006-3.wmv

Standard G50/03 w/720hp hot lapping around a track
http://netshow.inetc.net/ultimasports/TGLapRecord1.wmv

Is proof in the pudding? I don't know. The driver lapping around the track will push the transaxle more than I ever can. So we have 1/4mi runs, burnouts, and hot laps on video...Am I still concerned? Yes. Should I be? Not sure.

 

One other thing on the transaxle. Someone please check my math on this.

The G50/03 was designed to handle a max of 600 ftlbs of torque on a 3400 lb porsche.

The GTM weighs roughly 2450 lbs. This means the porsche weighs 30% more than the GTM.

Increasing 600 ft lbs by 30% = 780 ft lbs of torque for the GTM.

I will also consult a professional physicist to double check this.

 

The G50/03 was designed to handle a max of 600 ftlbs of torque on a 3400 lb porsche.

Where did you get that info? I 'thought' early non turbo transaxles had below 300ft lbs of torque capacity as rated by porsche.(although a conservative rating)

David

 

A video of a car making a run with that power and that transaxle is a far cry from putting 50,000 miles on it without maintenance. YOu have no idea how many times they might have had to repair things in those transaxles. On a track...possible replace it during a race and certainly tune it up after every race. A video is not representative of somethings longevity.

 

Hayabusa02: You are absolutely right. I was thinking about that last night as well. The factory can rebuild the transaxle whenever they feel like it. Who knows how many times it has been done. On the other hand would a reputable company like Ultima suggest a stock G50/03 to its customers if they know it will go down the tubes just after a year or two? Wouldn't they make more money if they asked their clients to buy a beefed up transaxle from themselves instead of telling people they can source it where ever they like? Especially if it would help with the reliability or longevity of the vehicle. Their reputation is very important to them. Would it make business sense? Again I don't have an answer to any of these questions.

 

On the other hand would a reputable company like Ultima suggest a stock G50/03 to its customers if they know it will go down the tubes just after a year or two? Wouldn't they make more money if they asked their clients to buy a beefed up transaxle from themselves instead of telling people they can source it where ever they like? Especially if it would help with the reliability or longevity of the vehicle. Their reputation is very important to them. Would it make business sense? Again I don't have an answer to any of these questions.

Well..what does a stock Ultima have for power? Is it 700? or is it a stock LS engine. MY guess is it is a stock LS engine just like ours is and with teh same 350-450 HP rating. A 700HP car is definitely not what the company is planning for as a stock basic option. And I highly doubt they were saying G50/03 for that upgrade.

 

David: Erik at Carquip post #12 "If you are content that the G50/03 will do the trick, make sure that you strengthen this gearbox in every way possible. It was not designed to handle torque over about 600 ft/lbs. "

 

I was referring to what Porsche rates the transmission at.

BTW, the gear sets are all pretty close, or are the same. Its the ring gear and case strength that comes into question with the non turbo boxes.

If your not investing big money in the box, give it a shot and report back....

David

 

Hayabusa02: I called the Ultima Factory at 011-44-1455631366 and asked them about the gearbox.

He said they use a stock G50/03 without additional reinforcements. They sell it for $5,000 USD. It can only be purchased through them if you buy the Ultima.

They said because of the light weight of the vehicle it can actually handle the power of the 800hp Ultima. They are so confident with the G50/03 that they offer a 12 month warranty with it. They said that all of the testing in the videos were with their stock G50/03. It is "absolutely bullet proof".

 

Ealingj. Welcome. We have built a 667 HP LS7 powered GTM with the G50/52 gearbox cryo treated and are turning 345/30R/19 PS2's, that's 13.5 inches a side on the back. If you go this route we might be able to help with tranny mount fabrication, dry sump, engine and trans cooling and a whole bunch of other stuff that we learned along the way. The people on this forum have been extremely helpful in our build and we would be glad to give something back if we can help you. I'm a first time builder and we made alot of changes; challenging for sure but I think you will have fun doing it! Good Luck

Jim

 

Ealingj,

Have you seen the post on gearbox spray cooling?
Is that something you're going to do?

 

WEll, I for one am curious. WIth all the different opinions and claims, I want to see someone who has >500Hp put 10,000 miles on an untouched G50. I didn;t want to risk it so I invested a lot in upgrading my G50-20, but I will put 50k miles on the car.

 

Ive got almost 3000 miles and 450ish HP on a stock used G50-20. I'll keep you posted (although I think 700HP is a complete and totally different situation)

David

 

Jeff Schwartz, without a tranny cooler. I am amazed myself, but it's true.
I don't even know how many miles he has on that Ultima now but it's a lot. He's been power touring it for years as well running the 0-200-0 classic challege. Still running the same gearbox untouched. A 50/52 I think.

Personally, I wouldn't run anything but a 50/50, 50/52, or GT3 in any high-hp app.

Jeff S has chewed through a bunch of axles though. Covered on another thread somewhere.

My 2 cents, and I in no way claim to be an expert, but I got to believe that whacking a trans with 600 ft/lbs with a N/A motor right from the get-go cannot be good. However, a motor that comes up semi-gradually, like a turbo motor, I just have to believe that is gentler on the gearbox.

Jeff