# Help with modded t-jets



## FastZ28 (Apr 12, 2012)

Hi all,
Been busy building a couple ECHORS SS cars for myself, my wife and my Dad. We race in my basement occasionally. I have a 16x4 tomy 4lane highbanked oval.
Well I've built a couple screamers here lately and we also run a mod t-jet class.
We used to use fray rules but recently switched to ECHORS SS rules for our little races and they are now faster than our mod t-jets.
One of my fray cars used to do about 3.1xx lap, my new SS 9 tooth car does 2.9xx lap , and the last SS 14 tooth car I built will do 2.3xx laps.

So my problem is how to make a mod t-jet faster than my SS cars.

I have built 2 new ones to try and go faster and have failed.

Car 1 was just refreshed with new brushes and cleaned and a AW magnet glued on the bottom. It has poly mags and a mean green, lapped gears and wiz brushes and pick-up shoes, a RTHO brass frontend and wiz .380 sili-sponges.
It will turn a 2.6xx lap.

Car2 is a fresh build, a nos truck chassis was hand selected and stripped.
It has all new everything, wiz brushes, rtho gears throughout, new rtho cluster shaft, rtho front end, new afx rear axle,a fresh Scrig quadralam, new nacho poly magnets, new wiz .380 sili-sponges and a new AW traction magnet glued on the bottom.
It will turn 2.7xx lap times.

This really has me stumped, I tried more/less brush tension and dash magnets, super 2 magnets and can not get any more speed out of it. Then tonight I decided to try again, I have an old t-jet chassis from when I was a kid that I installed brush cups in and a brass flanged tube in the bottom arm bushing. It really is an ugly sight with big gobs of solder holding the brush arms to the brush cups but anyway I decided to try swapping everything from car2 into this chassis because I thought I wasn't getting enough brush tension with the traditional setup. I took some old t-jet pick-up shoe springs and cut them to length so the the wiz brushes were almost completely out of the cups and assembled it. After I had it ready to run I oiled it and held it up off the track and revved it up and it sounded better, but it was still running roughly the same times as before. I also did the magnet swaps again and I also switched from the 14 tooth pinion to a 9 tooth pinion and all it did was go slower.

I really want to have a mod t-jet faster than a SS so what am I doing wrong?
I would like to run brushes so I don't wear out the motors/comm plates like I would running a wet comm setup.
Anyone has any input or experience playing with modded t-jets?

I don't thinks its power related either I have 4 individual power supplies I built for each lane. They are 20v 2A transformers going into full wave recifiers with capacitors. Well thats what they are rated but I am getting a solid 23.5V and about 10A per lane. There is 2 power taps on my track, one on the front straight and one on the back straight. We also run poly/neo traction magnet G3's with no issues. My fastest G3 I built is a BSRT G39/39 double wind, stock sg+ motor mags and poly tractions that will turn laps of just under 1 second flat.


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## Boosted-Z71 (Nov 26, 2007)

You might try some shunts or "tiger tails" from brush electrics to the pick-up shoes, every fast T-jet I have built has more time in the shoes than anything else, especially the hanger area, so if this is a true "outlaw" class racing the first thing I would do would be the shunts.

Boosted


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## slotking (May 27, 2008)

I used to race with a group of guys who ran a any arm rule.
me and another guy would race with them once in a while.
we could often win with a fray car.

you can get down the straights pretty fast, but you really have let up for the turns

so even though the mod is faster down the straight
the SS should be easier to drive


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## slotking (May 27, 2008)

forgot

we also used to race AFX non mags, with any arm and weight pans
we stopped racing them when people where winning races with fray cars


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## alpink (Aug 22, 2010)

yes, the FRAY/ECHORR SS 9 tooth formula seems to be really good. I have some 12 tooth pinions and some 14 tooth pinions built to the same specs and, as has been said, although they are quite a bit faster in the straights it is difficult to learn the curve combination to maintain the speed.
it would seem that being able to keep the armature RPM up a little more through curves enhances the overall handling and allows later braking.
I sometimes use my 12 and 14 against Hank, Scott and Ed's 9 tooth and I can pull them all on the long straights. I cleaning out accelerate out of the curve and get to top speed quicker with a faster top speed. but I don't have the finesse, even with a 9 tooth (which is mostly why I drag race) to get through the turns like many, many others do.
it WOULD seem that the various combinations of parts you have described would be faster than a 9 tooth, but Ill say that lending my 12 and 14's to thew other guys rarely results in them running away from the better drivers with 9 tooth.
I shall be seeing a lot of ECHORR guys on February 16 for the Lehigh Valley (Allentown) Merchants Square show and race and present this question.
if you attend and find any of those guys between heats, marshaling and wrenching, they will happy to answer questions. especially Anthony. LOL!


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## slotking (May 27, 2008)

al

your about right on, but there is 1 difference here.
he said he is running a


> a fresh Scrig quadralam


with poly mags!

he should be blasting down the straights
but should also have heavy breaking and not be able to float the turns.
plus he has to stop(slow down) short of the other cars.

I had a 20' track with lots of straights but the turns where still an issue

the 14t gear should soften it up some


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## FastZ28 (Apr 12, 2012)

Boosted-Z71 said:


> You might try some shunts or "tiger tails" from brush electrics to the pick-up shoes, every fast T-jet I have built has more time in the shoes than anything else, especially the hanger area, so if this is a true "outlaw" class racing the first thing I would do would be the shunts.
> 
> Boosted


Thanks Boosted, I was thinking of trying that but when I added shunts to a poly-magna it only made minimal gains, about half of a tenth. I still may try it.



slotking said:


> I used to race with a group of guys who ran a any arm rule.
> me and another guy would race with them once in a while.
> we could often win with a fray car.
> 
> ...


Well in my case this is a banked oval so the turns are not that big a deal. The mods only seem to get up to speed faster but I don't think they are faster down the straights.



alpink said:


> yes, the FRAY/ECHORR SS 9 tooth formula seems to be really good. I have some 12 tooth pinions and some 14 tooth pinions built to the same specs and, as has been said, although they are quite a bit faster in the straights it is difficult to learn the curve combination to maintain the speed.
> it would seem that being able to keep the armature RPM up a little more through curves enhances the overall handling and allows later braking.
> I sometimes use my 12 and 14 against Hank, Scott and Ed's 9 tooth and I can pull them all on the long straights. I cleaning out accelerate out of the curve and get to top speed quicker with a faster top speed. but I don't have the finesse, even with a 9 tooth (which is mostly why I drag race) to get through the turns like many, many others do.
> it WOULD seem that the various combinations of parts you have described would be faster than a 9 tooth, but Ill say that lending my 12 and 14's to thew other guys rarely results in them running away from the better drivers with 9 tooth.
> ...


I think you misunderstood me here a little bit. The mods are faster than the 9 tooth cars, but not faster than the 14 tooth cars. This is also a banked oval where the turns aren't that big of a deal.
I also plan on going to the Allentown show and was planning on bringing some cars to run on your dragstrip :thumbsup:


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## slotking (May 27, 2008)

ok

so if you were drag racing the cars, the mods are close to the SS cars???

If that is true, then yes there is an issue.

1>what ohm is the quad?
2>how are you brush springs set? 
proper tension will be important with a hot setup
3>no binding anywhere
4>is the arm timed? advance or retarded

also, drop some dash mag in the car and see what happens? better or worse


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## cwbam (Feb 8, 2010)

sorry to barge in, 
but isn't it the nature of the beast with TJETs?
A chassis can run great 1 day, put it away '
and 2 weeks later the same chassis same track and its a dog (relative to race/ lap times)
I'd like to see some photos


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## Dyno (Jan 26, 2009)

Put braids on the pickups and it will run with a stock Tyco 440x2. The polymer magnets actually seem to slow a mean green down unless you use braids. First try the car with regular magnets. It probably will improve in speed. Next put on braided pickups. You will be shocked. Then try the polymer mags again. Also put in a longer guide pin to help keep you in the slot. The car will ride a little higher with braids.


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## alpink (Aug 22, 2010)

haven't seen mention of limiting pick up shoe travel?


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## Dyno (Jan 26, 2009)

alpink said:


> haven't seen mention of limiting pick up shoe travel?


Very good point


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## gonegonzo (Jan 18, 2006)

Fast ,

It looks like you've taken too big of a step all at once . A big short cut . All of the mods you've made had been at once . My idea would be to get your chassis running at least with an ECHOOR S/S car . One by one make the mods and record the performance with each . Also , a lot of it might be with the arm and the mags not being compatable . 

After the improvements have been made and you have it running with the S/S car , thennnnnnnnn start fine tuning . Gearing , Shunts , tiger tail etc . But , record the performance to see if it helps . If it doesn't , take iut away so not to interfere with other mods .

Many time the "go fast " ideas don't work out on every build . I hope this helps .

Gonzo


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## FastZ28 (Apr 12, 2012)

Just to give you guys a update I got my quadralam running pretty good now.
It turns out it didn't like the wizzard brushes. It also didn't like a regular t-jet chassis. 
I first threw in a set of silver afx brushes and it helped, but then I switched it all over to a tuff ones chassis and it became a beast! It runs great with either the Dash magnets or the Nacho polys. Corners better with the polys, but straight line speed is about the same.
Now I just need some good replacement silver pickup shoes. Anyone know of any?


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## Dyno (Jan 26, 2009)

Solder some braids on whatever shoes you have on it and watch it really take off.


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## Ralphthe3rd (Feb 24, 2011)

Hey FastZ28, that's an odd conclusion that the Tuffy chassis is somehow better ? The only dif is that it has Silver plated electricals. And alot of guys think thats pointless, and even remove the Plating from Tuffy or A/FX chassis electricals. There must have been another factor involved in the chassis swap, like maybe better brush spring tension ? And silver plated pick-ups shouldn't make a dif either ?....at least not by today's revised beliefs !
Just MY .02 ¢


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## Dyno (Jan 26, 2009)

Tuff ones chassis hold a much better spring tension and those xcelerator arms like a lot more current than a stock motor. So the greater spring tension allowed the brushes to effectively apply more current to the armature. That's just my opinion.


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## Bill Hall (Jan 6, 2007)

What Dyno said!

Due to tuffer "sproingage", the guts dont sag out the bottom because of fatigue as readily as the earlier units. With in reason, this keeps the tension adjustment where ya left it save for brush or upper bushing wear.

Ralph, It's the part they dont tell ya when ya get all hopped up on goof balls and wanna try the Xcellerator/T-jet conversion. Somewhat common knowledge after you try them and re-assess the inevitable shortcomings. You'll have more ying and less yang if you use the Tuffy chassis. Still just a morphidite drywall cutter unless you have a proper speedway or regulation drag strip.


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## Ralphthe3rd (Feb 24, 2011)

Thanks Bills, I didn't know about the Tuffies Extra "sproingage" ! So now I'll file that away in the old grey matter, for future use....thanks ! :thumbsup:


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