What is Max HP From Bolt-Ons ?

[Davey G]

My '78 280Z is my daily driver, and already had a valve job when I bought it 10,000 miles ago. It always starts, reves to 6K, runs great. Stock the car is 150 HP (170 S.A.E. HP) and at 2900 lbs any additional HP or weight reduction yields good results. It seems to me like 40-50 extra HP would go a long ways with a 2900 lbs car toward making the car more fun, less sluggish around town and on the freeway. So to my questions:

 

Can 40-50 HP gains be had with bolt on equipment without tearing into an otherwise great and dependable engine? I'm thinking headers, exhaust, mufflers, K&N filters, etc. or are those add-ons only going to net around 15 extra HP? Or am I going to need head work, triple ground valves, flat top pistons, lighter flywheel, etc., etc., to get there and maybe more?

 

I thought I'd ask the guys who know..........................dg

[dsommer]

First thing I would do is dyno the car to create a baseline HP figure.

 

 

Next look at aftermarket cam, header and a cold air intake with a K&N filter.

 

Or just yank the L28 and install a V8!

 

[JSM]

Copy / Paste from this thread:

http://forums.hybridz.org/index.php/topic/95316-braaps-l6-efi-induction-advice-and-tips/

 

CAMS and the OE EFI system;

 

The OE EFI will NOT tolerate larger than stock cams, (large enough to make any difference one would spend money and time to swap out), and there is no “reasonable†way around it. If you desire a cam for EFI L28, do yourself a favor and steup to aftermarket Engine management which will allow you to tune around the new VE curve the cam delivers and also delete the AFM from the air stream. The stock Z car EFI isn’t tunable enough to compensate for an altered VE curve. I’m sure someone could hack the resistors and caps in the ECU, but with Mega Squirt being so inexpensive and readily accessible now…

 

The OE EFI will barely tolerate extreme exhaust mods and minor head work, (those two items with the stock cam and stock EFI intake manifold don’t alter the VE curve too much and what they do alter we are able to compensate for with a variety of methods). The OE EFI will not tolerate freer flowing intake manifolds. Both of those alter the VE curve drastically enough that there is no reasonable way to keep the part throttle cruise AND WOT in balance. You will have to sacrifice one for the other and at that, if you spend too much driving around in the compromised region of the tune, the tune could be far enough out to actually foul plugs, which means that when get back into region that is correct for the engine, it wont run right due to fouled spark plugs.

 

In summation, if you have the stock EFI, keep the stock cam and stock intake manifold. If you desire an intake manifold and/or cam change be sure you also have an alternative engine management system that allows the end user to tune and make use of what the cam and intake manifold brings to the table in performance gains.

 

 

Paul

[Pyro]

it is more like 135Hp at the tires for a 78.

 

Mild cam and free flowing exhaust will make a fairly big difference. But compression is low (8.3:1 cr), so not much cam can be used. Maybe you can pick 20hp with a mild regind cam (260 degree) with a header and 2-1/2" exhaust.

 

increasing the compression to 10:1 with some flat tops and using a 280 degree cam could get you another 20hp, thus reaching your +40hp goal. The stock intake and stock efi system becomes a hp bottle neck very soon (say, at 160hp) .

 

installing a 81 to 83 5 spd and a 3.90 gear (stock 81 to 83 setup) makes a nice improvement for 3rd and 4th gear acceleration.

 

 

 

It would be better to first install a megasquirt 2 efi system then bolting on a stock turbo system. You can easily make 225hp with the stock engine with 10 psi of boost and a intercooler. But then the stock clutch will burn up in short order.(a 2+2 clutch will fix that)

[Drax240z]

Can 40-50 HP gains be had with bolt on equipment without tearing into an otherwise great and dependable engine?

 

In short, no, in the way you are asking the question.

 

But if you consider a turbo or a supercharger a bolt on... YES.

[Davey G]

Copy / Paste from this thread:

http://forums.hybridz.org/index.php/topic/95316-braaps-l6-efi-induction-advice-and-tips/

 

CAMS and the OE EFI system;

 

The OE EFI will NOT tolerate larger than stock cams, (large enough to make any difference one would spend money and time to swap out), and there is no “reasonable†way around it. If you desire a cam for EFI L28, do yourself a favor and steup to aftermarket Engine management which will allow you to tune around the new VE curve the cam delivers and also delete the AFM from the air stream. The stock Z car EFI isn’t tunable enough to compensate for an altered VE curve. I’m sure someone could hack the resistors and caps in the ECU, but with Mega Squirt being so inexpensive and readily accessible now…

 

The OE EFI will barely tolerate extreme exhaust mods and minor head work, (those two items with the stock cam and stock EFI intake manifold don’t alter the VE curve too much and what they do alter we are able to compensate for with a variety of methods). The OE EFI will not tolerate freer flowing intake manifolds. Both of those alter the VE curve drastically enough that there is no reasonable way to keep the part throttle cruise AND WOT in balance. You will have to sacrifice one for the other and at that, if you spend too much driving around in the compromised region of the tune, the tune could be far enough out to actually foul plugs, which means that when get back into region that is correct for the engine, it wont run right due to fouled spark plugs.

 

In summation, if you have the stock EFI, keep the stock cam and stock intake manifold. If you desire an intake manifold and/or cam change be sure you also have an alternative engine management system that allows the end user to tune and make use of what the cam and intake manifold brings to the table in performance gains.

 

 

Paul

 

Yep, read the whole thread already. Braap is the man for engine builds! It was actually as a result of reading his EFI thread and Massive Headwork threads that led me to formulate my question - Without changing cams, EMS, pistons, valves, head gaskets, injectors, intakes, fuel rails, etc., what can I expect to get from K&N on the intake end and header/exhaust mods on the other end as far as additional HP? Maybe nothing, because the intake is restricted in the first place, the AFM measures flow and not mass and humidity coupled with a very limited EMS, and restricted by the smallish valves and without valve curtain relief work, porting, matched pistons to optimize squish on the peanut chamber, etc?

[Davey G]

installing a 81 to 83 5 spd and a 3.90 gear (stock 81 to 83 setup) makes a nice improvement for 3rd and 4th gear acceleration.

 

The car was originally a 4-speed, but we dropped a 5-speed tranny in it during the refurb.

 

What rear end came in a '78 with 4-speed tranny?

[Davey G]

In short, no, in the way you are asking the question. But if you consider a turbo or a supercharger a bolt on... YES.

 

Sorry, I should have qualified my question with "...and keep it NA."

[JSM]

On the other hand, my buddy had a bone stock 77. He left the stock EFI electronics alone other than running 280zxt injectors and adjusted the AFM.

 

His mods:

Stock Turbo Motor / Head

Stock J-Pipe

Ebay T3/T4 Turbo

Exteral WG set to 8PSI

3" Exhaust

 

The car was very quick and I was shocked he never blew it up! He walked my highly moded, carbed car without any problem.

Edited February 22, 2011 by JSM

[BLOZ UP]

the AFM measures flow and not mass and humidity coupled with a very limited EMS, and restricted by the smallish valves and without valve curtain relief work, porting, matched pistons to optimize squish on the peanut chamber, etc?

 

The AFM also has a IAT embedded in it. But yes, it still is limited.

 

I bet you can find 20hp just putting in 91, advancing the timing, and retuning with Megasquirt--everything else bone stock air filter to tail pipe tip.

[Davey G]

I knew I was asking the right guys.

 

Sounds like I'm kidding myself to expect much with just bolt-ons only, though they would be well utilized with the other engine mods. The car will stay my daily-driver for the foreseeable future, but driving it daily with 200-225 HP would be more fun! So I'll plan on the engine mods come rebuild time. I'm sure I'll have some questions for you at that time. Thanks for the help and perspective.

 

Davey G

[johnc]

Please search a bit Davey.

[Davey G]

On the other hand, my buddy had a bone stock 77. He left the stock EFI electronics alone other than running 280zxt injectors and adjusted the AFM.

 

His mods:

Stock Turbo Motor / Head

Stock J-Pipe

Ebay T3/T4 Turbo

Exteral WG set to 8PSI

3" Exhaust

 

The car was very quick and I was shocked he never blew it up! He walked my highly moded, carbed car without any problem.

 

Wow! Seriously, Wow!

[frank280zx]

Davey,

There are a million ways to more HP some are pricey some are cheaper.

I personally found out when i had to have a car running but my engine wasn’t finished, that a flat top NA engine ( euro spec in this case so slightly more compression) with a e88 head ( or if you can find a Maxima head) Will bump compression enough to make it a very fast little car.. This was with the stock cam, stock ECU but a 55MM TB and a MSA header and some mild headwork.

So my tip if you want it cheap and relatively fast;

-Source a late NA block

-Source a e88 or maxima head

-Get a mild port job or just clean and port match your runners yourself

-Order a ISKY ( iskanderian) Cam kit for mild street use ( a rally cam if you may)

-Get an MSA header and a free flowing exhaust

-swap the complete engine and sell yours

 

This could all be done around a 1000 us i guess (cheaper to but better do it right) Further if cash permits you might consider chopping weight by adding Fiberglas parts here and there, talk to John for that

Edited February 23, 2011 by frank280zx

[Pyro]

should be 3.54 gear. But a lot can happen to a car in 35 years

 

didn't think a 78 would come with a 4 speed.

 

75 or 76 did come with 4 speeds, I thought the 77 and 78 came with 5 spds.?????

 

what year 5 speed did you put in?

 

 

It is easy to throw a turbo on a z engine. I have done 5 turbo installs on Z's. My first was on a ragged out 78 with 200K+ miles. Just lock out the ignition advance and set timing to 26 degree at idle, use a 8:1 fmu for fuel enrichment, add the stock turbo exhaust manifold, turbo, wastegates, oil lines, and j-pipe. Then my old car ran a 14.6 at 96 mph and beat my buddies V8 1990 mustang. Can do a turbo setup like this for under$ 300.00 in used parts.

 

Later did the same thing in a 76, but used a better turbo, 12 to 14 psi of boost, 7.4:1 cr, intercooler, better fuel pump, better clutch. ran 13.7 at 108 mph in the 1/4 mile (bad traction). Locked out timing and FMU's will work ok at low boost, but not very well over 10 psi. So, much better to just do a megasquirt efi system first.

[Tony D]

IMO, "terrible question"...

 

Bolt-Ons are not what you need to look to, I will repeat this again for the sake of your edification.

 

I got a 76 S30 with triple Webers, Header, and exhaust. Car felt hot... I mean my butt dyno said this thing was a screamer.

 

Of course the Dyno-Jet said it made 87 or so HP.

 

Off came the Webers, and sold were they.

Off came the header, and given away it was.

 

I installed the stock 176,000 mile EFI system we took off our Bonneville car that was sitting in a box. I installed a proper N42 Cast Iron Exhaust Manifold with an MSA Downpipe to mate to the 2.5" crush-bent exhaust that was already in the car (to which I added a BIG Glasspack---one of those 36" mothers that fits under the tranny!)

 

Then, with attention to detail the timing was set, valves adjusted, blah blah blah...

 

Car spun the same dynojet to 147HP.

 

You want 50HP? How about almost 70...from basic maintenance and proper performance tuning.

 

Quit looking for the 'Magic Bullet'---optimize what you have, and until you are making AT LEAST 147HP on your stock system, consider the fact that 'something ain't right' and you need to fix THAT before looking for some 'magic bullet' to give you more horsepower.

 

Putting bolt-ons to a sub-optimal car is not the way to do it.

 

Your question was 'how do I get 200HP from an N/A S30 L28' and that thread already exists.

 

Sure, I got the answer: bolt on the complete Slovers head with Isky cam, and a set of 44PHH Mikuinis and spend some $$$ on dyno time with a five gas analyzer...

[Tony D]

" It seems to me like 40-50 extra HP would go a long ways with a 2900 lbs car toward making the car more fun, less sluggish around town and on the freeway"

 

So will a 3.90 with an early five speed and an 11# flywheel.

 

It will be a different car with those two mods alone. No engine changes required at all.

Sluggish comes from three things:

 

1) Gear ratio in the back set up for 'fuel economy' and not 'performance'---the world got 3.70 with a four speed, and 3.9 or 4.11 with a 5 speed (in the JDM you get a 4.38 with a 2/2 and five speed...)

2) Heavy stock flywheel that masks response to throttle inputs.

3) People who don't freakin' know how to drive and think the L28 is a Small Block Chevy and expect performance below 3500 rpms when they floor it. Do us all a favor, drive the car in the proper gear for speed, if you are not going 60mph, you shouldn't be in fifth...hell, fourth is a stretch for 60, actually. Normally that is 3rd gear territory if I'm accelerating down an onramp for commuting. (and it would be the top of 2nd with my 3.70 if I was in my turbo car...)

 

Consider well these facts.

[Davey G]

should be 3.54 gear. But a lot can happen to a car in 35 years

 

didn't think a 78 would come with a 4 speed.

 

75 or 76 did come with 4 speeds, I thought the 77 and 78 came with 5 spds.?????

 

what year 5 speed did you put in?

 

The 19 year old previous owner put the 5-speed in, saying it was from a 280ZX. I don't know how to verify that other than let my mechanic look at it. It's been a good transmission.

[Davey G]

IMO, "terrible question"...Quit looking for the 'Magic Bullet'---optimize what you have, and until you are making AT LEAST 147HP on your stock system, consider the fact that 'something ain't right' and you need to fix THAT before looking for some 'magic bullet' to give you more horsepower.

 

Tony D

 

I agree, and have been doing that type tuning for a year now. Even the "Z specialist" mechanic says it's one of the best running stock 280s he's seen in a while, though we have not dyno'ed it. We've tweeked the timing, the AFM, etc. I have the stock cast iron manifold, the original downpipe, going into a stock sized (1.75" ?) newer pipe with only the stock resonator/glasspack, no muffler.

 

Davey G

[Davey G]

" It seems to me like 40-50 extra HP would go a long ways with a 2900 lbs car toward making the car more fun, less sluggish around town and on the freeway"

 

So will a 3.90 with an early five speed and an 11# flywheel.

 

It will be a different car with those two mods alone. No engine changes required at all.

Sluggish comes from three things:

 

1) Gear ratio in the back set up for 'fuel economy' and not 'performance'---the world got 3.70 with a four speed, and 3.9 or 4.11 with a 5 speed (in the JDM you get a 4.38 with a 2/2 and five speed...)

2) Heavy stock flywheel that masks response to throttle inputs.

3) People who don't freakin' know how to drive and think the L28 is a Small Block Chevy and expect performance below 3500 rpms when they floor it. Do us all a favor, drive the car in the proper gear for speed, if you are not going 60mph, you shouldn't be in fifth...hell, fourth is a stretch for 60, actually. Normally that is 3rd gear territory if I'm accelerating down an onramp for commuting. (and it would be the top of 2nd with my 3.70 if I was in my turbo car...)

 

Consider well these facts.

 

Yes, I believe I have too steep of a rear end. 60 IS a stretch for 5th gear, and I try to not shift to 5th until 65+. When accelerating on the on-ramp I wind 3rd out to 65-70. I can tell the car likes those rpms, at least with the rear end I currently have. If traffic is cruising at 55-60 I am in 4th. MPH does not suffer from this type driving...it helps it.

 

Sounds like better next steps would be a 3.90 - 4.11 rear end, lighter flywheel, and see where that takes me, and make decisions from there.

 

I've learned a lot about the car in the year I've owned it. I am not concerned to keep the car stock like some over on classiczcars.com are; that's why I'm asking "next level" questions here at hybridz.org. I appreciate all the help from those who have owned theirs for much longer - thanks guys!

Edited February 24, 2011 by Davey G