Help 60ft our jy turbo tercel

Ok....

So some friends and I built this tercel out of some junk and used parts. It’s gotten faster and faster each trip to the track but despite my holding the brakes with my iron leg you can only hold it back on the converter until 2800rpm or so. Problem being our turbo doesn’t spool until mid to high 3k rpm. 

We don’t want to spend anymore money on the set up, and we’ve trapped as high as 98mph so we know we have the power to run reasonably quick. But our aem fic won’t support launch control and nobody is making a high stall converter for a Toyota tercel.

I know that you grass roots enthusiasts know how to make junk go fast. So where can we look to help our 60ft for free.

In reply to 1SlowVW :

I don’t have anything to contribute other than to say “build thread or banned!” Imagine getting smoked by a terdsel?

_ said:

In reply to 1SlowVW :

I don’t have anything to contribute other than to say “build thread or banned!” Imagine getting smoked by a terdsel?

Here you go, also I don’t need to imagine, I have smoked others and been smoked by the car.

https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/the-party-ice-story/136974/page1/

Smaller turbo?  Nitrous at the line to get more exhaust volume / spool?   Vornado?

Damn, that's about equal to my M3Ti. I guess I need to go faster to not be blown away by a tercel

In reply to AngryCorvair :

We have thought of nitrous, but it’s around 12$/lb up here...so that’s not budget friendly. (Not on a 600$ drag car)

We did consider a smaller turbo, but I think the lag is helping save our rods. 

We’re really leaning towards swapping to a coupe shell and ditching the slushbox. It’s kind of a shame because the car is really easy to run consistently right now...but I feel like with a stick and decent clutch we could get the thing to leave a lot harder.

Unless some Toyota guru can tell us another oem torque converter that we can bolt in and have a higher stall.

Thinner fluid?

I'm no expert, but there has to be a way to get a looser converter. Either look at other toyotas with similar transmissions (but maybe heavier cars that would've needed more RPM to build before moving off?), or just the old school method of DIY modifying a converter, there has to be a way to do it.

I also like the thinner fluid idea for nearly free.

I’m no expert on hooking up a FWD car, but what have you done?  Is it load jacked?  Tires?  Wheelspin?  Pressures?

Your 98 mpg number rings a bell- the Mumpkin ran 98 mpg too.  But we did 1.6 second 60’ launches, and cut more than a full second off your quarter mile times. 

Of course, that’s a bad comparison. That car was RWD, manual trans, running full drag slicks. 

But my first question is are you hooking up?  Are you lacking traction, or lacking torque?

Hows your gearing?  Is it bogging at the start, or running out of steam at the end of the track?  Is it near the top of a gear at the finish, or does it upshift 90% of the way down the track?

Can you adjust the shift points on that car?

These might help with traction:

http://gusmahon.org/html/traction.htm

basically corner weight the car and shim/adjust the sway bar to balance the weight on the front tires, then add an air shock in the rear opposite the driver to help slow weight transfer off the opposite corner of the car.

The converter is hurting you, so I’d look at how to modify one DIY style (they are all pretty similar) or have one made.

Here’s some info on Torque Convertor modifications, etc.

https://forums.nasioc.com/forums/showthread.php?t=101950

Compressed air system to help counter the lag?

Shooting it through the exhaust could spool the turbo faster. Shooting through the intake could simulate the effects of the turbo while it came up to speed naturally.

A solenoid connected to an RPM activated switch could send the shot of compressed air in just above your stall RPM.  

Stefan said:

Here’s some info on Torque Convertor modifications, etc.

https://forums.nasioc.com/forums/showthread.php?t=101950

This is interesting.

SVreX said:

I’m no expert on hooking up a FWD car, but what have you done?  Is it load jacked?  Tires?  Wheelspin?  Pressures?

Wha

 

Your 98 mpg number rings a bell- the Mumpkin ran 98 mpg too.  But we did 1.6 second 60’ launches, and cut more than a full second off your quarter mile times. 

Of course, that’s a bad comparison. That car was RWD, manual trans, running full drag slicks. 

But my first question is are you hooking up?  Are you lacking traction, or lacking torque?

Hows your gearing?  Is it bogging at the start, or running out of steam at the end of the track?  Is it near the top of a gear at the finish, or does it upshift 90% of the way down the track?

Can you adjust the shift points on that car?

What we have done it doubled the horsepower and install falken azenas.

The car spins first at about the 4ft mark when it spools. Once it shifts to second it hooks great. This is on a well prepped track.

It pulls pretty hard the whole way down the track and we go through the traps at the end of 3rd. We’ve been able to increase mph by adding boost but the additional wheel spin means we’re not any faster.

We've looked at putting a separate manual boost controller in the system to have it run 10-12 psi in first then go to 15 in second. In hopes of getting the best of both worlds. But that just maintains our 60ft it wouldn’t improve it.

You might simply be torque limited. 

Have you tried the additional boost with wider/ taller  front tires?

You need to have the power at the start, and put it to the road. Your spool time followed by wheel spin is limiting your launch. 

First step is getting rid of that wheelspin at spool.  You need that power. Wider/taller front tires, lower pressure, and maybe softer front springs. 

Then consider smaller turbo, narrow hard rear tires, and weight jack the car (lift the rear, lower the front, add subframe connectors)

I think you are leaving a little on the table with your suspension/ chassis tuning (but honestly don’t know the right things to tell you for FWD drag racing)

Good luck!

Since the car spins in the first 4 feet I think you have a tire issue. Even if you could make boost right off the bat you would just be spinning so at this point its not a stall or RPM issue. Falken azenis are usually an autox type tire right? You might be working against yourself with a tire like that. (handling type tires generally have stiff sidewalls, and while the grip is good, the acceleration in a drag racing setting isn't great as the tire can't 'wind up').

I'd try to nab a set of FWD drag slicks (like 22x8 or something). If you get them used you might be able to find something really cheap. Heck, even a snow tire with low air pressure might be better than an autox tire.

BTW - I think your car and your times are already pretty awesome. I also think a small slick would put you in the 13s.

Robbie said:

Since the car spins in the first 4 feet I think you have a tire issue. 

Shoot, that’s a typo. I meant a 40 feet. And if I’m thinking about it it’s more like twenty. We roll off the line and have to wait half a second to a second for boost.

We run falkens because that’s what I had laying around, and they were paid for. I know it’s not ideal. Especially since we can’t do a burnout with the auto to heat them up.

Also thank you, the car is very impressive for how little we have in it.

Hang on....

You are never gonna launch on the Falkens. Period. 

If you are trying to solve a launch problem, you have to have tires you can launch on. 

aha, 20-40 ft makes more sense!

Still, a SMALLER diameter tire will help your gearing and help your car get to boost faster. It could also make the spin problem a bit worse, so you might have to tune your right foot.

Less weight ......

    Start with a lawn tractor battery, instead of that huge battery.  They come in 3 different ratings, but all are the same weight, cheap and light. 

SVreX said:

Hang on....

You are never gonna launch on the Falkens. Period. 

If you are trying to solve a launch problem, you have to have tires you can launch on. 

What your saying is I need to find some good used small diameter slicks.

What tire pressures are you running?

In reply to 1SlowVW :

I am saying that you have done the bulk, and are now looking for the fine tuning. You can’t do 100% on crappy tires. 

Hard sidewall tires are great for cornering, but they are terrible for launching. 

The smaller diameter might be a good idea, but it will reduce your contact patch and increase your wheelspin. 

Smaller diameter usually helps low powered cars. But if it leaves you grabbing for 4th in the last 30’ of the track, it’s gonna hurt your times. 

Well I just had a friend reach out to me with a set of 22x8x13 mt slicks. He said they would clear the fenders on my mk2 vw.

But it sounds like we may need to fit them to the tercel for the weekend.

I feel bad for being late to this thread because it seems like noone has even mentioned the problem you posted about, which is that you're pushing through the brakes without being able to fully stall the converter (and possibly launch with a little boost). Anything that's been mentioned about changing converter stall or spooling the turbo is not going to let you leave the line with more torque than what your brakes are currently holding.

I suspect your power brakes simply aren't working correctly. Brakes work more or less the same in both directions. What i mean by that is that your brakes can probably manage .8g+ in deceleration, maybe even over 1g. I would bet money that if you measured your acceleration coming off the line at 2800rpm with no boost, it would be less than .2g.  In general, a car shouldn't be able to push through its own brakes until it has the power to run 12s or better, or in other words to manage the same force of acceleration in 1st gear as the brakes can manage in deceration. This suggests that the brakes just aren't working right. I would look at your brake booster check valve to see if it's leaking. 

If you determine that your brakes ARE working correctly, the only thing you can do to increase their holding power while staging without actually changing parts is stage, put the car in neutral, rev it up almost to redline, and cram the brakes on decel before shifting into drive again. The reasoning for this is that your power brakes work off vacuum and you make higher vacuum decel'ing from high rpms (~25") then you do at idle (~18-20" with stock everything) so you're giving your power brakes a boost with the stronger vacuum.