bigbreak_2000

I want to get opinions on possible root causes for larger than average power losses that occur between the torque measured at crank and the torque at the wheels for a 280zx (s130). This is not about arguing this a good/bad dyno machine, not questioning the reputation of the engine builder or ECU tuner. I just want to get a general sense of what power losses others are seeing, kind of getting an idea of what % loss would be considered normal, or what would be exceptional high that justify further investigation, and ideas how one go about root cause analysis. I may be overlooking something very obvious in my car that cuases a 1/3 power loss between the crank and wheels. I want to put my mind at ease with the numbers, or go after something that would provide a noticable benefit. Don't ask me for names of the engine builder , the person who made the exhaust system, designed the intake system or who the tuner is, several are on east coast, other one west coast, and all of them have either international or national levels of experience working with race teams be that with Datsun/Nissan, Austin Martin, engaged in regional and or national scca as drivers or supporting cars, etc. There are some big names. So here is my situation: iStarted as a bone stock 1981 280zx 2+2, NA, 5speed. Bought the car with extremely low orginal miles. The car is in Charlotte NC. Everything stock except for new tires and new OEM exedy clutch, on Mustang dyno we had 129whp. Factory rating was 145hp. Not too bad. Very low power loss IMO. This was kind of my benchmark. Then I put a highly modified 3.2l NA motor in, pacesetter header, excedy stage 1 clutch good to 270whp, KN cone filter, 2.5 in mandrel bent ss exhaust with only 1 back muffler. Took car to same tuner shop, Engine builder dyno (with pacesetter header on, but without kn filter, and without my exhaust system) at 287 crank hp, on the chassis dyno best I ever saw was 215whp. Thats a 25% difference. I had it to various tuner shops, Dyno Jets, Mustang they were all pretty close, so I concluded its not a tuning (fuel/spark) issue. The engine was in best state of tune for where it is. Recently I decided to modify the engine further. ITBs, new high com head, bottom and ECU still the same. The engine with the ECU and header was tuned again and on the chassic dyno turned out 340hp at 6700rpms and 297 torque at 5500rpms. That is much better than the single TB setup. Swopped the stock diff for a new quaife lsd and same gear ratio. Put the engine back in the car, add air filter, connect the same exhaust as before, and for comparison purposes now we're getting 240whp at 6500 rpms and 197 torque on the wheels at 5500 rpms. No signifcant changes were made on the street tune (from the tune/ECU settings provided by the engine builder). I'm not hung up on HP numbers, torque is what matters and I want to get the best bang for my buck, and this is a larger than 30% loss between crank and wheels that I need to understand what is going on. Ok I get it, more power equates to higher friction and temps and one can expect a higher loss ratio. But is 33% loss acceptable? I heard other Z car owners with a similar engine setup see 270whp, So my expectation to see higher numbers does not sound unreasonable, or is it?. The gearbox shift good, no noise or anything weird, the clutch seems to held well, no burning/slipping, Car drives good, nothing strange with the differential. The entire drivetrain is just very smooth. I cant tell if there are any underlying issues with the u-joints, it just feels like a new car, no vibrations, clunks or anything. Engine sounds good, accelleration/pickup is excellent with the ITBs. However in the numbers someting does not seem to add up: is a loss of 100lbsft of torque between the crank and wheels acceptable or what could cause such a large difference? If one argue 20% loss is more of an average on these older rwd Z cars, then I shoudl be making closer to 230-240 torque at the wheels, and looking at explaining where am I loosing the other 20-30 lbsft of torque? I just cant think that an exhaust system backwards of the header , or an airflter can cause an engine to loose that much power. Could it, or is there a possible drivetrain issue I need to look into? I could upload pictures if someone thinks it is worth to see what the intake or collectors/exhaust system looks like. If one of you are in Charlotte NC I would also be happy to take the car to someone to have a look if they have experience solving these overall car setup issue. Im willing to change the exhuast system if someone convince me it would make that difference.

rule out any issues with the air regulator or aux cold start injector by just unplugging them and then see how the motor runs.

I would agree with Domzs approach. Apart from the money factor, I read the best solution is to keep the stock airbox with a K&N filter: 1. its mounted outside the engine compartment for colder air, 2. the airbox shape and fitment helps air to pass through the radiator and no over. The restriction of the stock airbox is on the intake side prior to the filter element...to overcome this drill a few quarter size holes (5, or 6) on the box. The elbow and tubing on my 280zx is stock 3 inches so that is not where the restriction on flow is. But I guess it also depends on the use of the car and where you want the HP/torque to peak. For autocross you may find best to have peak power at lower rpms, and for that I found it ideal to fit the filter as close to the TBs/plenum, and thus eliminating any tubing. The further I moved the filter away the engine peaked at higher rpms (it moved my powerband about 500-600 rpms up).

with that type of built and high CR on a Mustang dyno you should make north of 200 WHP. It also peaks early. What ECU are you using and what was the AFR?

I don't have the dynosheet with me at the moment but I think it was 230 (maybe240?) ft.lbs of torque at 4000 and peak just over 290 at 5700rpms. Max HP was at 6700 so its a very decent power band, and should give good speed in the gears...I say "should" because I haven't driven the car on the road yet after the upgrade, as I'm still waiting on the rotor/hats from Coleman. But that power is with the airbox on. What is interesting is that the motor, without the airbox, would make the same power but peak torque at 5200 rpm. So the goal is to get a good street tune with the airbox on, and ideally move the airfilter as close to the TB as possible (but still keeping the intake air at a decent temperature). I'll post some runner measurements soon and compare to what you've got John. Keep in mind mine is slightly larger capacity at 3.2L and have the 70mm TB.

Finally have the ITB conversion complete. Dave did a great job, here's a picture of what the intake looks like. Now just need the brake setup completed, then its back to enjoying the car.

My plan was to install Bilsteins front and back but the rears would have taken 8 weeks to order from the factory in Europe so I decided to put Bilstein inserts in the front and Tokico blues in the rear. I could get the rear Bilsteins from Australia quicker but then the cost just doubled. I'll see how the Tokico's work out, perhaps I'll keep them on, or eventually switch over to Bilsteins on the rear as well. Lowering spring set from Tokico. I wanted GC progressive springs but could not find them anywhere. I expect with the Tokico springs it will further lower the center of gravity by about one inch. I have BFG G-Force Sports on, 225/50-15 on 8 inch wide wheels 0 offsets. They are already lowering the car and pretty stiff sidewalls. All my original OE rubber bushings are good and I don't want to change over to urethane as I still use the car on the street. Also kept the stock sway bars. My goal is not to stiffen it too much and keep some travel in the suspension. I haven't progressed far enough yet to know what alignment adjustments will be needed, I may end up doing slotting on the rear. The engine is still out of the car, doing mods for a goal of 360hp on a NA setup. Also putting a Quaife LSD in and waiting on custom rotor hats from Coleman. Im only doing bigger wilwoods in the front, with a 11 x 1 inch rotor. The stock rear disc brake setup is good enough. I'm not bothered to much with the rear suspension. Wish the rear spring rates on the Tokico's were a little bit more stiffer (I have the longer 2+2) but actually traction with the old motor (218whp) was excellent. There is some advantage to squatting right? I haven't decided on the pads yet, and once the car is on the road will see if I need bigger MC or prop valve to balance it out Let me know what you think about the tokico setup.

BMAC, I'm doing a similar upgrade, but for a 1981 280zx. I think the 81 had a larger M/C than the 79. I'll let you know how it turns out (It'll take 2-3 weeks since I'm also doing suspension upgrades which I'm waiting on parts)

The tires are brand new BFG G-Force Sports. The fronts are 205/55-15 and the rears are 225/50-15. The interior seats are all stock (very comfortable and top notch condition). The question the Hypercoil engineer had for me, and unfortunately I don't have the vehicle with me to go check, is what's the design of the stock spring at both ends: closed & ground, closed & not ground ends, open & ground ends or open & un-ground ends? Can anyone tell me what this is on the stock 280zx? I did a quick google image search on the aftermarket springs for the ZX and it looks like all the ends are open and un-ground, Which may imply Hypercoils are not an option unless I convert to coilovers with proper spring perches. For those using the Tokico springs, what is your experience, are they good quality springs? I'll call MSA to get the spring rate on them.

Let me know what condition they are and how much you want for them. Originally the Lowering Springs sold as a Kit with # 6302.140

On the 280zx 2+2 my goal is to firm the ride up and lower the vehicle about 1 - 1.5 in F&R. I can still get Bilsteins B46-0057 for the rear (max length 20.69 vs stock 21.15) and for the front I'm planning on using the Bilsteins P30-0264 for the '84 300zx N/A (max length 20.77 vs stock 21.3). According to Bilstein they should be fine for using with a 1 inch lowering spring. I need help on how to decide which spring would be most suitable to use on the 280zx, with the Bilsteins. I was thinking a F 175/ R 200 lbs/in should be fine for street driving. The car is not gutted. The wheel tire combination is 205/55-15 F and 225/50-15 R which is an overall almost full 1 in smaller tire diameter. Tokico (progressive): 140lbs front / 165lbs rear and somewhere else I read they are in fact constant….175 F and 200 R Suspension Techniques: 125lbs / 182 lbs - maybe too soft Eibach (progressive): 68-148lbs / 85-306lbs - no longer available Ground Control Coilovers: 200lbs / 225lbs - maybe too stiff? I don't want the car to be bouncy or too hard on the street. Making coilovers just seem overly complex for my need. I heard Hypercoils are very good quality springs, and an excellent choice for racing, but then what length, stiffness and coil diameter is recommended? I did a rough estimate on the Hypercoil application and the recommendation turned out 185 F and 220 R stiffness. Here are the specs on the stock 280zx springs Free length F 12.78 R 14.07 Spring constant lb/in F 126.6 R 140.6 Coil diameter F 5.91 R 3.94 wire diameter F 0.512 R 0.472 I am not educated in how to choose a suitable spring. I have an installer that will do all the fabrication and installation and alignment , but I obviously want the installation to be as easy as possible (using as much as possible of the stock suspension components).

Can anyone tell me where to buy or who can supply a front and rear shocks and lowering spring set for a 1981 280zx 2+2? This is a street car, I want a firm but not hard ride. Will be using 15x7 and 15x8 wheels, 0 offset. What I have in mind is lowering about 1-2 inches, 175/200 rates (this is about 50% stiffer than stock), perhaps little more but don't want too hard (200+) for a street car. Would prefer Bilstein shocks. I think the OE replacement part numbers for the Bilstein sport shock is Front: P30-0069 and Rear: B46-0057 but I cant find them in the US. Unfortunately it appears the Tokico HP 255 kit is not adjustable in the rear and the slightly stiffer than stock. GC may be too stiff, so looking for something in between and a good quality that can be modified/adjusted. I know a custom coilover kit can be made with Koni yellows, but then I heard the Koni's are not ideal, they are race shocks and for a street car may be too hard. I have no technical knowledge or experience to compare one shock to another, need advice...

I want stronger brakes, less unsprung weight and able to keep my options to run either the 14 inch stock wheel for street, or use a 15 inch wheels for summer and track use. So I don't want to ditch my wheels and tires just for the sake of larger rotors. I'm really in favor of lightness. So I did some research on what the 510 racers do with adapting the 280zx rotors, and the idea I have is to go with Wilwood Forged Dynalite Caliper on the Front, Billet Dynalite Singles on the Rear. Perhaps I could retain the stock rotors or go with even lighter Willwood 10.25" Ultralight vented rotors. I read this combo will reduce the weight of the brake setup by about 10 lbs per wheel. Front: wilwood forged dynolite 4 piston part # 120-6806 http://www.wilwood.com/Calipers/CaliperProd.aspx?itemno=120-6806 Rear: wilwood billit dynalite 2 piston part # 120-4060 http://www.wilwood.com/Calipers/CaliperProd.aspx?itemno=120-4060 1. Has anyone else attempted this conversion on their S130? Any hints on fitment aspects will be appreciated 2. With the stock 14x6 inch 6 spoke wheel are we limited on the ZX to a 10 inch rotor or will a 11 inch rotor just fit? I see others fit the 10 inch ZX and 200sx rotors on 510's and they use 13 inch wheels. My question is more in general on rotor diameter, I understand there are other clearance aspects to consider (wheel offset, wheel design, caliper dimension etc) 3. Does anyone sell Wilwood caliper adapter plates for mounting the mentioned 2 type of calipers to the 280zx strut? 4. Can anyone recommend which Wilwood light 10" rotor & hat to use (what is the required bolt pattern)? 5. What is the stock ZX caliper piston diameter for the front and the rear on these vehicles? (this is a 6/81 production 2+2).

Redline made a great difference. Although my gearbox only has 20,000 original miles on (I bought the car from a guy who stored it for 30 years), the shifts are smooth and it definitely is more quiet than what it used to be. I really can't complain, I think it was money well spent.

My car is 81 280zx 2+2 and has the stock datsun 5 speed g/box. I have a 3.2l stroker (non turbo)in it, that currently puts out over 218 Mustang dyno whp with the P79 head, n47 FI intake and mild cam. We're putting a p90 head, ITBs and bigger cam, so the goal is about 240-250 whp. I read many places that Nissan went with the T5 in later model S130s because the standard close ratio 5 speed can't handle more that 180-200 hp. Mine's been holding out well over the last 3 years since I had the 3.2 in it. It also has the stock r200 3.9 with stock U joint on rear axles. The only other upgrade I have is a light flywheel. No problems so far. No weird noises or vibrations. I also use redline oil in the gearbox. Along with the engine intake changes I am putting in a LSD. I do not drag race or autocross. Should I really be concerned that the gearbox will have a much faster rate of wear and eventually destruct because of the amount of torque applied through the drivetrain? I could buy a cheap T5, recondition it, but then I'd also have to do modifications to the driveshaft and mounts. I want to hear what your real world experience has been with the stock 5 speed mated to a much stronger motor. Has it hold up well under racing conditions, when had you seen it actually failing, etc. I really like the ratios on the stock 5 speed. 1st is low , but 2nd-5th is an excellent match for the torque strong 3.2l. If anything I wish 2nd was higher geared, to get to 60 you have to switch 2-3rd and that is a rather long action. A short shifter would have been nice but cant have that on the stock 5sp. So I want to stay with the stock 5sp if the risk of it breaking is not that large. If I do have to go to a stronger g/box might as well consider a WC T5 or some other g/box.

Guys I need your expert advice here. I have a 81 280zx 2+2. I can't decide between the basics of a custom coilover setup vs. a Tokico setup similar to what FricFrac describes in this discussion (assuming the Illumina adjustable struts for the S30 F&R and the Tokico springs for the 280zx). Another source with years of experience in Nissan racing told me the the Tokico approach with 280z adj struts and 280zx springs is a relative easy setup for a S130(with cross member slotting in the rear, and can't remember if he said camber plate in the front will be required). I also heard from another source that the Tokico's springs are too soft for the heavier 2+2 ZX (especially the rear...one need at least 200F, 250R rates for the ZX) and the struts on the firmer settings are too hard for street driving. Especially in my situation I am concerned , I have a srong stroker motor in it, and the amount of squatting is unreal. Unfortunately there is no one in the local Z club that has a Tokico setup on a ZX that I can ask to drive the car and get a feel. The car is mostly street driven, never autocrossed, and maybe at most see 50 fast laps at CMS a year just for the fun of it. I do want a firmed ride, lower by 1-2 inches, but not a harder ride than say a newish stock M3 or Subaru STi. Sorry these are about the only real world comparisons I can make. Not to hijack your discussion on S13 coilovers, but the coilover setup I had in mind is basically the same as the 510 kit from either Troy Ermish or Arizona Z or Technotoytuning. All kits I believe can be configured with Koni inserts. My sense is that long term a coilover setup may have benefits = when your goals change (where and how you drive) the setup may allow easier adjustment. And from a resell perspective, potential buyers may consider that the coilover allow more options for changing to different struts. However from an installation ease and cost perspective the s30 Tokico's may be the way to go on a ZX.I just don't know how complex it will be to install custom coilovers on a ZX. What other factors need to be considered? If you go with coilovers, does it limit your options for bigger 12.2 brake kits and how would it limit your wheel/tire specification?

delete the topic

interesting discussion. I was asking someone the other day about ideas to improve the intake manifold on my 3.2L stroker. The motor is fuel injection. Although the N42 intake had been port matched, and I'm running a 70mm TB on it, it actually lost power (10% down from the previous street cam) after we put the bigger cam in. So the conclusion drawn is with the bigger cam (duration/overlap) the motor really needs more air, and even distribution of that. So he hinted at the idea of custom fabrication - taking a tripple carb manifold and convert it to FI. Has anyone actually done this stateside and have dyno results to show? Tony please scan that article, I am very curious just to see a picture.

are you taking orders or is the design still in progress?

I have a 3.2L motor with fuel injection. If you have experience or know someone who have experience in tuning race engines, and know the L6 motor, and located on the east coast (Im in Charlotte NC), please send me your contact information. I need someone to tune it in with a new cam. I had a 27C cam in the motor which ran ok, but then had a 63DI cam installed and the power is on average 10% down across the entire speed range. The motor was built by a very professional and reputable race engine specialist on the west coast. They build many Nissan motors with the 63DI cam and there is something not right with mine. I dont need just a good local mechanic or someone who can do fuel and spark timing on a dyno, I need someone who knows the mechanics of these race motors and can look over the entire setup and bring it to its full potential. The motor runs on 93 octane and is NA. I would prefer that the work be done in Charlotte or else I can ship the car if the distance is reasonably near. The reason I am here seeking alternatives is due to the cost and inconvenience of sending the car/motor all the way across to the west coast.

I have restored a 81 recently and the parts becoming pricey these days are the distributor with the e12-80 ign box attached to it. The collectors are also paying higher prices for the AFM if it is clean and working. You may also want to keep the disk brakes and rotors as they are a nice upgrade for the S30s, and the rack and pinion steering box is much better than recirculating ball. Like everyone else is saying, the gearbox and R200 differential. If it is a 2+2 you may want to consider keeping the 240mm flywheel and just have it lightened to 18 lbs. If the damper and radiator is good condition keep it. The starter is also a nice upgrade for the S30s. I may want the cam if it is still original and not regrinded. The bumper shocks (I actually need one, Rear left!). And if the brake booster and master cylinder is in good condition keep those. And lastly, the safety belts. Some of these items may be worthless to some but gold to others.

I misstated in my original post, the problem is not going to fast into corners. My main frustration with the stock suspension setup is that now with the added engine power, power on existing a corner, the front becomes very loose. It is just plain frustrating to hold much of that power back till I'm down to a full straight. Applying power in corner and the the car would start to push wide. I noticed with the summer wheel/tire setup with the rear diameter slight higher than the front it is a bit better. In part may be better gripping and stiffer sidewall tires in the front, but also I think with a slightly higher roll center in the back it may have helped. But I want the rear end to stiffen up more. So to get more steering, do I need to add a stiffer rear sway bar, or do I just need to add stiffer rear springs or is truly going to take a combination of all those things? I called a few Z car part shops and the very first recommendation is replace the stock oil filled shocks with gas filled shocks. I am at a total loss understanding how changing to new shocks will help. Should I just accept that the Tokico HP shocks for the rear will be noticeable stiffer and more responsive than the old oil filled shocks? Since the Illumina (what I heard is better than HP's) is no longer available for the rear, I'm afraid with the Tokico shock kits to put Illumina's in the front and HP's on the rear that stiffening the front is what I think I don't want to do. All my local club members are familiar with the S30s but have very little experience with the 510 or S130. Maybe I just need to call John at Beta Motorsport. Any other recommendations?

I am very tempted to get my vehicle ready for Autocross and want to see if there is someone on the forum with experience re. proven setups on their 280ZX. My car is a 1981 2+2, 5 speed and stock in all regards except the following: 3.2L NA stoker engine (225whp) on street gas, lightened flywheel, standalone ECU, non stock exhaust system. I would truly be a beginner in the Autocross classifications. Other than the modifications mentioned the car is stock as it came from the factory: the car has 20k original miles on so original disc brakes setup (NOS pads however upgraded to DOT4 fluid), Nissan 6 spoke alum wheels with new 195/70 - 14 michelin tires, and appears to have the very original shocks and in as-new condition - perfect height level front and back per FSM - no sagging yet that I can tell). It is a late 81 production so it has power R&P steering. The diff is 3.9 R200 and the gearbox is the 5 sp with low 1st and long OD 5th. I do have an optional set of aftermarket wheels and tires that I put on as a summer setup; those are BFG GForce Sport 205/55-15 (7 wide front) and BFG GForce Sport 225/50-15 (8 wide rear). These tires have excellent grip, no scrubbing with the wider wheels, but rather large fender gap as you can image with the stock springs and shocks. I do drive the car on the street and it is tuned well for city driving (lots of torque in lower RPM and exhaust has 2 mufflers so it is not too load even with header) however I can tell the brakes and suspension are not on par with the performance level of the engine. It is not a car I would dare go fast into corners. Ive been couple times to the track at CMP and there is no way this car, even with the abundance of power, can be competitive with much lesser powered stock class modern cars. My goals are far from professional road racing, so my question is really what can be done as a Phase 1 project for decent upgrade to get braking performance and better handling and steering? Many had told me the brake setup on the 280zx is good, just need better pads (hawk or another brand?). The car is not a daily driver so I won't mind a stiffer or somewhat lower ride as long as it is not bone jarring hard or too low. I've also been told the aftermarket bushings may make the ride very hard but I cannot decide if that is more important to upgrade vs. installing modern gas struts, thicker sway bars, or stiffer springs. All I know is the car will hold its own to many performance cars on a straight line, but nose dive heavy on braking, pushes very very wide on power-on fast cornering, suspension feels soft and feels like a boat compared to my other newer cars. I'd like to avoid too many modifications with the first project, for ex. don't want to start cutting or welding to the suspension component, but looking for advice on relative easy to do mods that would give good results such as which pads, bushings, sway bars, shock and spring combinations might be good for a beginning. Thanks I've read of other 280zx owners being successful in the ITS class, apart from them being good drivers I wonder what changes they had made, and what the SCCA allowed them under the Stock or Street Prepared classes.

I'm experiencing an issue I hope someone can help pinpoint to a probable cause. I have the stock fuel rail from a 280zx Turbo, and then also a stock pressure regulator that (has 2 inlets/1 outlet and a vacuum connection) and fits right into the stock fuel rail. Also uses the 280zx turbo injectors. There is no cold start injector (the intake is modified to accommodate a MAP sensor). The engine had been running well for past 3-4 years since I had it installed. Recently, occasionally (I will explain this more), soon after start up fuel will spout out past the connections to the pressure regulator. I assume something is causing a pressure built up. Switching engine off, let is rest, then restart may cure the problem. What can be going on here? Had anyone seen this problem with a faulty pressure regulator, or could it be a clogged injector causing a spike in pressure, what else? Background: It always smelled a little heavy of fuel during the cold start up cycle, which I thought was rich tuning, combined with a by-result of running an open crank vent system (tube on block vents to atmosphere via catchcan). The other morning about 1 mile into driving I experienced an engine fire - it was driving fine but I started to smell rubber burning and could see black smoke coming from the engine. Some wire loom got melted. Could not see where fuel was leaking from, however stain marks on the block pointed to a few manifold bolts that felt a bit loose and thought perhaps fuel/oil mist from the intake could be seeping out onto the hot header. After tightening those, I drove the car a couple times and did not experience any further issue. You can switch to the On position, with pump running, and no fuel will leak. Subsequently I also got my insurance to inspect it and they paid me to get the melted wiring replaced. Yesterday after the car had been sitting for a week, I wanted to take her out for drive. I started the engine, popped the hood to see if everything still looked ok, and to my dismay saw fuel streaming out from the fuel rail. Now I know where it is leaking from. In the pictures I show the pressure regulator so you can see the style, the other shows the top side of one of the fuel hose connections and it appears a little swelled at the top section, and the other picture shows where the hose pushed with my finger upwards, it felt very soft and thin and you can see how easy it deforms just by the slight pressure of my finger. These are fuel hoses supplied by Nissan. Could they have gone bad (were new 4 years ago)? Perhaps the heat exposure from the header made then soft? In the picture you can see I recently installed my own fabrication of a modded stock heat shield plate, covered with a layer of thermo-tec header blanket material.This was installed after the first fire incident.

Pallnet, sent you a PM. One more piece of information is I don't need the cold start injector. Please add pressure gauge in your cost estimate so I can decide on that. Since the motor currently run with the stock turbo FPR (with the 2 inlets/1 return for fuel, and one vacuum line), I dunno what other FPRs will fit at the end of the custom rail. Any recommendations on a supplier for the regular appreciated.