zpetna5015 Posted July 21, 2015 Report Share Posted July 21, 2015 any ideas as to what i can do to increase the performance without an engine swap? 1 Quote Link to comment
datzenmike Posted July 21, 2015 Report Share Posted July 21, 2015 Yes. The biggest bang for the buck is to change your rear end to something with 'shorter' (higher numerical) gears. Your 2wd Z22 720 probably has a 3.889 differential in it. Check the engine tag under the pass side hood hinge on the inner fender. Lower right corner it may say HF38 this is Nissan speak for 3.889 ratio Find a 4.11 or better yet a 4.375 and fit it in. Do not use one from a 4x4. Also get the speedometer gear inside the transmission and swap it into yours to keep your speedometer accurate. The speedo gear is matched to the differential and they must be kept together. A 4.375 rear end is 12.4% higher. This will increase the RPM 12.4% higher at any speed you are at with your 3.889 gears. This means the engine can multiply it's torque by this amount more and accelerate away faster. It has no effect on the engine and no changes need be made to it. You simply give up some top speed and gas mileage. The engine does not need nor is it stressed by expensive high performance parts. It's simple wrench turning you can do in a morning. differential is likely $50 at a wrecking yard. Use the engine tag to identify the one you want. 1 Quote Link to comment
Rhino13 Posted July 21, 2015 Report Share Posted July 21, 2015 Yes yes yes ^^^ just went from 3.73 to 4.11 and its absolutely worth it. First is very short, but when you drop second it takes off more than I expected. 1 Quote Link to comment
datzenmike Posted July 22, 2015 Report Share Posted July 22, 2015 3.70 to 4.11 is 11% change. I recently changed the same ratios into my 710. WOW. It PULLS!!!!!!!!! . 2 Quote Link to comment
zpetna5015 Posted July 22, 2015 Author Report Share Posted July 22, 2015 Does it have To be the same year? Quote Link to comment
Brohemius Posted July 22, 2015 Report Share Posted July 22, 2015 No. Rhino13 up there swapped his gears with a 620 truck. (he has a 720). Quote Link to comment
zpetna5015 Posted July 22, 2015 Author Report Share Posted July 22, 2015 Thanks! Any other ideas? Webers or something else? Quote Link to comment
datzenmike Posted July 22, 2015 Report Share Posted July 22, 2015 All 520/521/620/ 720 (2wd at least) and 4 cylinder 2wd D-21 Hardbodys had the H-190 differentials in them. The Hardbody usually had lower numerical ratios and aren't much good for this. Besides, the720s had a tag that identified the rear axle ratio. One stop shopping. Most 620s are 4.375 with the exception of the early L16 automatics (4.625) and the '79 4 and 5 speed. (they were 4.11) If from a 720, avoid the 4x4s as the drive shaft flange changed around '82 to something larger. Quote Link to comment
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