TOUGH TORQUE CON­VERTER

A DURABLE TORQUE CON­VERTER OF THE RIGHT SIZE AND STALL SPEED WILL MAKE THE DIF­FER­ENCE IN ALL-AROUND PER­FOR­MANCE ON THE STREET AND/OR AT THE STRIP.

Mopar Muscle - - Contents - BY DAN FO­LEY • PHO­TOS BY THE AU­THOR AND TCI AU­TO­MO­TIVE

A durable torque con­verter of the right size and stall speed will make the dif­fer­ence in all-around per­for­mance on the street and/or at the strip.

With an 825hp Ray Bar­ton Street Hemi go­ing be­tween the fend­ers of our ’65 Coronet pro­ject (alias “Cool Blue”), we knew we’d need a tough, well­built torque con­verter. Stall speed and dura­bil­ity are of the ut­most im­por­tance when se­lect­ing the right con­verter for your com­bi­na­tion. Hav­ing the right stall speed con­verter has the great­est im­pact on the per­for­mance of your car, whether it’s at the strip or drive­abil­ity on the street. De­pend­ing on the build pur­pose of your ride, the con­verter needs to match both your de­sires and the en­tire com­bi­na­tion. When a con­verter is the right size (8, 9, 10, 11 inches) and stall speed for your com­bi­na­tion, your times­lip and/or street per­for­mance will be at its best.

For many, in­clud­ing long­time en­thu­si­asts, it’s some­what of a mys­tery in how torque con­verter func­tions. We’ve also heard that as it spins, it mul­ti­plies the torque pro­duced from the en­gine to the trans­mis­sion’s in­put shaft to help move the ve­hi­cle with more force than a man­ual trans­mis­sion. This mys­tery is ac­com­plished by the fluid dy­nam­ics pro­duced in­side the con­verter. As this hy­draulic power trans­fer con­tin­ues, its fluid cou­ples through the con­verter’s in­ter­nal com­po­nents (tur­bine, sta­tor, im­peller pump), thus mul­ti­ply­ing torque to move the car down the road and/or track.

The in­ter­nal parts can be ma­nip­u­lated to get a con­verter to be­have a cer­tain way or have a spe­cific stall speed. The per­for­mance and stall speed will be de­ter­mined by which parts are used to build the con­verter. The im­peller pump fin an­gles and sta­tor blade de­sign are the pri­mary com­po­nents used to change stall speed and torque mul­ti­pli­ca­tion. A torque con­verter man­u­fac­turer will make changes to each of these parts to dial-in where the con­verter will be­gin to stall.

Just se­lect­ing a con­verter off a web­site or cat­a­log isn’t the best way to get your

car to per­form at its best or get the best e.t.’s at the track. All the ma­jor torque con­verter com­pa­nies will be glad to work with you to help you get a con­verter that’ll fit your per­for­mance goals. To de­ter­mine the stall speed and what size con­verter you’ll need, the con­verter man­u­fac­turer will need in­for­ma­tion about the ve­hi­cle’s com­bi­na­tion. Specs like camshaft pro­file, en­gine power, and peak torque, peak horse­power, gear ra­tio, tire size, and ve­hi­cle weight are just a few of the specs needed. The more info you can pro­vide, the bet­ter the torque con­verter can be matched to your combo for max­i­mum per­for­mance.

For our street driver, Street Hemi Coronet, we con­sid­ered some of the great con­verter man­u­fac­tur­ers like Turbo Ac­tion, ATI, Dy­namic, Trans­mis­sion Spe­cial­ties, and TCI. We’ve used each one of these rep­utable com­pa­nies’ torque con­vert­ers through the years with­out a sin­gle is­sue. A few years ago we tried a TCI 10-inch Ul­ti­mate Street Fighter torque con­verter. That TCI unit helped a friend’s car run a 10.46 at 130 mph with a pre­vi­ous best of 10.52 at 128 mph us­ing a dif­fer­ent brand 10-inch con­verter. The 60-foot time also im­proved from 1.50 to 1.46. While street driv­ing it showed less low rpm cruise slip­page and bet­ter throt­tle re­sponse, mean­ing it was a more ef­fi­cient con­verter with less of that slip­page feel. Now five years later, my buddy’s A-body has made over 50 10-sec­ond passes, and it has over 5,000 street miles — that durable unit was our de­cid­ing fac­tor to go with a TCI Ul­ti­mate Street Fighter con­verter.

We let the TCI tech­ni­cian know the Coronet’s pri­mary pur­pose was to be a re­spon­sive street driver that’ll put down good power when we chas­sis dyno test and tune. Once the B-body is well sorted out with a few hun­dred street miles, we’ll flog it once for a strip-test, just to see what it’ll do. Low­est e.t. isn’t our big concern, but with 825 hp at the crank, low 10s should be doable on 275/60R15 drag ra­di­als.

Check out the pic­tures the good guys at TCI took while they custom-built our tough torque con­verter. TCI says The Ul­ti­mate Street Fighter bridges the gap be­tween their full com­pe­ti­tion units and Su­per Street Fighter con­verter. It’s built to han­dle up to 1,000 hp for ex­treme street ma­chines, fea­tur­ing furnace-brazed fins, steel sta­tor, nee­dle bear­ings, anti-bal­loon­ing plate, hard­ened pre-ground pump hub, and com­puter bal­anced. We’ll have plenty of con­fi­dence know­ing there’s a durable TCI con­verter teamed up with the bul­let­proof A&A Torque­flite we built in the pre­vi­ous story. It’ll be plenty tough to han­dle the in­com­ing, high-horse­power Street Hemi. Fol­low along and see how TCI builds one tough torque con­verter.

We chose a TCI 10-inch Ul­ti­mate Street Fighter torque con­verter based on (among other things) its proven re­li­a­bil­ity in a friend’s 10-sec­ond street car. It fea­tures a bil­let steel front cover, furnace brazed blades, steel sta­tor, nee­dle bear­ings, hard­ened pre­ground steel front hub, and anti-bal­loon­ing plate. It’s all com­puter bal­anced to sup­port 1,000 hp.

It’s tough enough to han­dle the in­com­ing 825hp Street Hemi that’ll pro­pel our ’65 Coronet.

A Torrington roller thrust bearing is placed in the cen­ter of the cover be­fore the tur­bine as­sem­bly is put in po­si­tion. The tur­bine as­sem­bly is con­nected to the in­put shaft of the trans­mis­sion. Fluid flow from the sta­tor and im­pel­lor pump force the tur­bine to ro­tate, mak­ing the car move. No­tice the furnace braz­ing of the fins for strength and longevity.

In this shot, no­tice how the ring gear was pre­cisely com­puter welded to the cover at four equally spaced lo­ca­tions for equal balance.

The folks at TCI took a few pho­tos while they custom-built our torque con­verter to match our ve­hi­cles com­bi­na­tion for the right stall speed. Here’s a look at the thicker and much stronger than stock Cnc-ma­chined steel cover (en­gine side) be­fore its ring gear is com­puter welded in place, and the con­verter as­sem­bly be­gins.

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