Topic: Noob r150f strength question

[Chello]

Hi all,
New to the board.

Just a quick question, sort of a "how long is a piece of string question". I have a 7mgte in a 1980 4x4 Toyota, I have a r150f behind it.
I am currently siting on around 300rwhp and around 800nm of torque, I was going to start leaning on the motor some more, ugrading the turbo.

I use the vehicle for off-road, not much in the way of hills around here in Aus for crawling and I want to drag race it. Using 27"-31" tyres on the strip aired down (unsure of which size yet). Is there anyone who knows how much abuse and or hard launching the transfer will take before giving up?

I know it's a little different direction to most things. But any help and replies would be greatly appreciated

[Snowtoy]

Members at 22rte-trucks.com or supratrucks.com, should be able to tell you more about the longevity of the r150 when running more hp than the stock 150/180 hp/torque that the 3.0 had.  While a few members her have done the 7mg and gte swaps, I don't know of any who have tuned it to the 300+hp mark, and I think most use the W series trans.  In the Supra community, the r154 is good for 3 times the original 230hp of the 7mgte, so you may be fine depending on the mileage of the trans, and where you start building boost.  Is the 300rwhp with just the basic power upgrades, or is that with running the Lexus v8 AFM, 550cc injectors, and 14-16psi boost as well?

[Chello [OP]]

t4 ebay turbo chinese copy. Lexus AFM, SAFC, 550cc injectors, MHG, ARP's etc. Changing to a t04z because the ebay one is starting to get flogged out, alot of movement in the shaft.

I will end up having to change the diffs, at least the front or upgrading a fair bit.

The box feels and shifts fine, just concerened with the transer, if the chain stretches or shears teeth from the gears?

Atm just auto lkockers in it aswell which puts a bit more load on everything. I have smaller tyres because it spins them rather than gripping, more worried if it does hook up what it will do

[Snowtoy]

The 5vze engine uses the same r150f trans and a left drop chain driven t-case, and with the factory supercharger it was supposed to be around 240hp, so the original chain driven case you are using might hold up, for a little while anyways.  Marlin builds transmission for both the Supra and desert racing community, an email into him or BigMike will likely give you all the info you need regarding the durability of the chain driven t-case.  If it wont work, you can swap in a gear driven case using an adapter plate.

If you still have the stock exhaust manifold, you can use a stock ct26 turbo that has been modified to 57 trim.  A lot of people in the Supra community go this route using the 57 trim ct26 and the mods you have made it is supposed to be good for about 450hp w/the right tune.

What amount of boost are you running?

[Chello [OP]]

18psi at the moment.

A few reasons for the t04z, water an oil ball bearing. With a .84 rear which better suits what I want it for. Running less boost to achieve the same power. And actually works out easier for me because I am in Australia, 57 trim etc aren't as easy/popular or as well priced as in the states and I feel that the garrett will be more reliable going from what i have read on various forums. Not to say that is correct though.

Thank you for your qick replies and information Snowtoy

[BigMike]

Hello Chello,

Thank you for bringing this thread to my attention. Snowtoy offered sound info on the R-series transmission, including their successful use behind built 7M's and Supercharged 5VZ's. As for the transfer case, we have done a great deal of upgrading these and have eliminated many weak links, primarily with our world's strongest input gear (info) and our world's strongest front & rear 30-spline output shafts (rear, front). The last remaining issue is related to gearing the transfer case super low for Rock Crawling, in that we need to increase the distance between the input gear and the idler gear. If you are not looking to build a Rock Crawler, and if you use stock 2.28:1 gears with our Total-Spline input gear and 30-spline outputs, the larger idler gear profile would offer great defense against stripped teeth resulting in a pretty stout transfer case.

The best real world example I can suggest is a 4.7-liter 2UZ-FE Tundra XXRA Rock Racer running our transfer case products as shown towards the bottom of this page: http://www.marlincrawler.com/steering/high-steer/25mm-steering-pin-upgrade-kit This rig is using an automatic transmission, so the drive train isn't seeing harsh burn outs, however it does often become airborne which places a huge shock load the moment the rig touches back down.

Please note the gear drive t/case does not use a chain.

The primary question that comes to my mind is how much does your truck weigh?

Also I find great curiosity in your posted engine output numbers. If you're developing 300 HP to the ground, how are you also developing 800 NM of torque to the ground? (I'm assuming 800 NM is RWNM since you've had it dynoed at the wheels) I don't have any formal experience with a 7M-GTE, but shouldn't a torque number like this also produce a RWHP of 600 to 650? I know the 7M is known for producing good torque, as it's stroke is larger than its bore enabling it to develop more torque than horsepower in stock form... But when you go for big power from a small engine the ratio must swing in the horsepower's favor... Unless its purpose built to only have a low RPM power band, which doesn't fit the purpose of a Sports car platform.
Now calling our resident 400-HP MKIII Supra owner reklund5 for some 7M-GTE tech advice!!!  



It is nice that you are using such small tires (more than 20-inches shorter than the ones on the XXRA Rock Racer rig), which is great news especially for your differential of choice.

Please let us know what your truck weighs and we'll discuss this some more!

Regards,
BigMike

[BigMike]

Sorry, despite you stating this in your opening paragraph, I didn't catch that you have a 1980 pickup. Is it under 3,000 pounds with the 7M in there?

[Chello [OP]]

Thank you for the reply BigMike.

I weighed it on a public weigh bridge with me in it came in at 1700kgs / 3747lbs, granted that was weigh bridge at a scrap metal place so who knows how accurate it is.

As for power output, I honestly not sure, according to the dyno sheet that what it showed. So yes, at the wheels, maybe it shows up different with the gear ratios and tyres. 4.88 stocks and around 31" tyres.



The motor is relatively stock internally apart for .20" increase in piston size.

As for the tyres, was looking at the 27-31 inch range for if drag racing it, as I fgured not only quicker from the line but less force on everything involved.

31 inch tyres for daily driving and the biggest I will go is 35" for off-road stuff mainly mud/clay here



It's a little different now, changing the intercooler set-up



Maybe alot heavier than it should be? At 3700 lbs?