Who makes headers for the early Q???

[boomstriker]

Looking at the stock headers, there is some pretty serious restriction at the collector just before the converters.Does anyone make bolt on headers with or without converters?

Thanks, Kirk

[Q45tech]

No, the oem headers are probably as good any car sold in US at that time [90-93]. Not counting exoticsThe small size of engine displacement means that even at 300HP only 350 CFM is injested and expelled as water vapor and carbon dioxide.

flow-rate = 0.75 * (1/2) * 6500 rpm * 274 in3 * [0.083ft/in]3 = 374 cfm.

So each header. precat and cat has to only handle HALF or 187 CFM

The JDM engines have no precats but the shape/ diameters are the same. They might yield something less than 10HP but are obviously illegal to use due to emission regulations.

Also the O2 sensors react differently to the different space shape [distance to the cats].......they read leaner requiring the ecu to enrichen the cruise mixture dropping the highway mileage by 5-10%..............yes we have tested a few. Not clear why this happens but it does. WATCH OUT that the back pressure doesn't drop so low that the EGR doesn't work as designed!!!!!!!!!!!!!!!!!

Headers have to be tuned to the exhaust cam duration and overlap to maximize gains.

Measure the back pressure [by removing O2 and fitting a tube to a pressure gauge] per standard proceedure.http://www.tfxengine.com/software7.html ... om....shtm

[AZhitman]

Dennis - As you know, BRM is currently developing a catback system for the 90-96 Q (not necessarily for huge HP gains, just for appearance, weight redction and sound quality).

In your opinion, are the pre-cats or the regular cats a significant source of restriction? As I am in AZ, I certainly can't do away with the converters. However, i'm considering some options:

1) Leave everything as is, just fab up a nice catback system with an X-pipe and some Magnaflows and retain the stock configuration.

2) Punch out the precats and swap regular cats with high-flow units.

3) Punch out all four cats and let 'er flow.

Any thoughts?

[elwesso]

As dennis has said, the cats in there are already high flow.... (am I allowed to say do a search to an admin.... )

No performance gains can be had over OEM things....

You COULD consider using JDM headers (or punching out the precats) and having someone reprogram the ECU so the o2 sensors dont read goofy.....

[elwesso]

You could always get Jesse James to make an exhaust system for the Q... Straight headers out the hood... That would be a new one!!!

[1qckser]

Actually if you do a search you can possibly find AGMs data on how much hp his headers made, he went thru extensive tunning and dyno time with a shop in australia, I know at one point he was considering selling them becuase a new design was on the way, the only problem is they wont fit the USDM cars because the steering is on the opposite side. You also have to remember that exhaust technology has come along way since 1989, you can improve on the manifolds and the exhaust system, its just a matter of how much you want to spend and how much of a % do you think is a cost worthy improvement. We have a executive in my town whom has a Japanese take out with the jdm manifolds, he has had no problems in the 3 years the engine has been in the car, he is also running a JWT ecu and I can tell ya that his Q is a runner, it has a nice tone to it and really moves out.

[1qckser]

AZ dont mess with the cats, the tq loss and the smell you will get and the crap on your rear bumper and tail lens will not be worth any hp benifits, I would however and I plane to doit to my car is remove the precats, other than that leave the other 2 alone.

[1qckser]

This is from an old post from AGM

AGMI/H/E, Cams, and ECU

Registered: Jul 2002Location: Posts: 139Car: The absolute best value I have spent on my car in terms of $'s per Horsepower were Ceramic coated mandrel bent headers.

The first upgrade to the exhaust system was only from the cats back. The biggest gains were made when changing the headers.

The interesting thing to note is with the improved exhaust flow, the car ran rich at the top end.

This was easily fixed with the first computer I used, being a Unichip which was used as a Piggyback to remap the fuel parameters.

I am a big believer in tuning an engine on the Dyno with a Laptop than just plugging in a preset chip.

Chally, if you do a full exhaust upgrade and a Unichip upgrade, you will get big gains in HP without spending big dollars.

Once I went past this point I had to spend more and more dollars for each HP gain.

Chally, apparently one of the better Ceramic coatings available in Australia is PowerKote based in Adelaide.

If you really want to find out the benefits of high temperature Ceramic coating, ring Jeff Garland at Exhaust Dynamics who built my custom exhaust system.

http://www.exhaustdynamics.com.au/

Regards

AGM

[HeavyDuty]

The only issue with my 155k mile cats was that they were just that, 150k mi cats. Serious black striations through the core when examined after 'punched'. Restricted.

I punched all four of mine in prep for two RandomTechnology.com metal core hi flows & a new H. Their standard cat flows 40% more than stock, the metal core, 40% more than that.

If I don't get goofy with piping diameter, I'll be legal as far as sound & sniff, with gains to be expected.

It would be hard to convince me a stepped tube equal length (tuned) header wouldn't yield sub 10% peak gains with a matched exhaust system.

[AZhitman]

OK - With that being the case, the first person to ship me a set of Q45 exhaust manifolds gets the first set of production, equal-length tube SS headers at cost.

[1qckser]

If you need em I got em, let me know and illheat up the bolts and take em off my spare motor that I have been playing with.

[1qckser]

Heavy how does it sound with out all for cats, did you get a wiered sound from punching out the precats? I know the 300Ztt guys are getting good gains from doing this, I just love playn with stuff, thats what being a car guy is all about.

[Q45tech]

What am I bid for a set or 2 of JDM no precats exhaust manifolds?

Flow is relative; "punched all four of mine in prep for two RandomTechnology.com metal core hi flows & a new H. Their standard cat flows 40% more than stock, the metal core, 40% more than that."

In theory all one can do is vacuum out the 9% of residual burnt gases that stay in the cylinder during overlap [the compression space].

Measure the back pressure and assume 5 psi [at the O2 sensor] is the very best you can get with any close to legal mods.

The Q runs rich anyway with or without any exhaust mods by design.........how JWT chip/ecu mod gets more than half its power boost by leaning the mixture.

The ultimate theoretical gain is 9% or 28 HP with open tuned headers [8 individual pipe through the hood].

LOUD Catbacks mighy hit 8-10, no precats and bigger cats might yield 6-9 HP but these don't add algebraically .......say 15-16 HP together.

[HeavyDuty]

Heavy how does it sound with out all for cats,

I was so disappointed that I achieved zero sound difference without them. But I've not allowed anyone else to drive it with me beside it to hear any difference at wot. Plus I have one of those evil JWT POP's & it probably overrides any exhaust note anyway.

This sounds lame, but the only difference I noticed was that I chirp second gear now without trying. I shoulda made a baseline pull like I am going to before doing anything else.

[HeavyDuty]

The Q runs rich anyway with or without any exhaust mods by design.........how JWT chip/ecu mod gets more than half its power boost by leaning the mixture.

I think that's true with a lot of cars, fuel cures or masks a lot of ills. Without the mandatory 92-93 octane their program would make for some nice preignition problems.

The ultimate theoretical gain is 9% or 28 HP with open tuned headers [8 individual pipe through the hood].

Per your calculations, what diameter piping are you using for that calculation? Any steps? Port matched? The quickest way for any of us to lose power with AZ's proposed headers is if the (headers, H, cat-back) are too large. I've noticed a common denominator in a couple of your posts, Q45Tech, that you use 6500rpm as kind of a base for your calculations. Is there a reason why you wouldn't also use 6900 or 7300? I'm sure there'll be a trade off loss of power somewhere lower in the band in order to achieve gains up top.

I'm just a dumb country boy, I appreciate your experience and calculating approach to everything you post. I'm just drawing on observations of many different applications, some similar to ours, where larger gains have been achieved with proper research. A lot of times those gains defied calculations.

LOUD Catbacks mighy hit 8-10, no precats and bigger cats might yield 6-9 HP but these don't add algebraically .......say 15-16 HP together.

LOL, right. I have a few guys that add up all their bolt-ons individually & claim they have 2x original output.

[Q45tech]

Just remove the entire exhaust system and dyno the car, that pretty well tells you what's possible.

Years ago spent a lot of time with DYNAMATION Professional Engine Modeling software.......used about 300 engine parameters [actual Q cams measured and paramatized into software] the entire intake/exhaust tract measured and modelled along with combustion chamber [everything down to piston valve reliefs], actual valve lift per degrees of cam rotation, etc, etc,

6 months of almost full time work [1,000 hours] burned into my memory.

The major bottle neck is the tuned length diameter of the intake runner feeding the heads [they are tuned to 5600 rpm*]. Same with plenum volume and the Helmholtz effect of the tapered feed/TB and air hose legth thru MAF to the air box feed horn.

* depending on temperature of the air column........watch the peaks vary in amplitude and shift frequency [+-4%] as the temp changes 32F-160F

Everything about the engine is tuned to maximize torque at 1800, 4000, 4600, 5000, and 5600.

To make the engine look better they found that the 6,000 rpm Horse power was almost equal to the 5,600 rpm power so marketing used 6,000.

I use 6,500 rpm as the best point one can probably achieve without changing things inside the engine as you would be fighting what was designed in.

[Eswift]

I have been working with Ricardo Wave, although with a different engine, and it seems to me that the length of the header primaries are quite important in a 4-to-1 setup.

...WIll be fabricating a manifold in the next few days to test gains on engine dyno.

[AZhitman]

What am I bid for a set or 2 of JDM no precats exhaust manifolds?

You could always donate them to a good cause, Dennis. Let me know if you'd like my shipping address.

Heavy, we need to talk - I'm thinking retention of stock diameter and configuration, with punched-out precats (or custom-fabbed tubular headers w/o precats), replace cats with the metal core hi flows, ditch the H in favor of the NASCAR-style X-pipe crossover, and finish off with a nice Ultraflow dual-in, dual-out with twin 3" tips.

[HeavyDuty]

The major bottle neck is the tuned length diameter of the intake runner feeding the heads [they are tuned to 5600 rpm*]. Same with plenum volume and the Helmholtz effect of the tapered feed/TB and air hose legth thru MAF to the air box feed horn.

Which begs the question of decreasing the boundary layer in the runners. Since we're not even going down the road of a different intake manifold.

http://www.nissaninfiniticlub....+Hone

AZ-"Heavy, we need to talk - I'm thinking retention of stock diameter and configuration, with punched-out precats (or custom-fabbed tubular headers w/o precats), replace cats with the metal core hi flows, ditch the H in favor of the NASCAR-style X-pipe crossover, and finish off with a nice Ultraflow dual-in, dual-out with twin 3" tips."

I think I'll be ok with 1.5% gains here, 3% there, etc. I'd much rather have an X as well. I'm all ears. Even having a mandrel bent stock configuration system would be better than the reduction bend setup we have.

[cweberj30t]

I have been working with Ricardo Wave, although with a different engine, and it seems to me that the length of the header primaries are quite important in a 4-to-1 setup.

...WIll be fabricating a manifold in the next few days to test gains on engine dyno.

Eswift,

You looking to fab some headers for the J? Let me know what you come up with.

[AGM]

I have dragged out some photos of my headers and stainless steel exhaust system and with Chally's help will post them here.

Regards

AGM

[Chally]

For AGM No.1

[Chally]

No.2

[Chally]

No.3

[QShip]

I have dragged out some photos of my headers and stainless steel exhaust system and with Chally's help will post them here.

Regards

AGM

AGM, what was the amount of horsepower you picked up by doing this?

[1qckser]

Looks goooood:D

[Eswift]

Eswift,

You looking to fab some headers for the J? Let me know what you come up with.

right not I am working on a CBR600F4i, and if i get into grad school I will have time to do some optimizations for the VG30DE once I take some measurements...

[Chally]

On behalf of AGM, he got about 50-54hp with the exhaust mods.Maybe there are different figures now AGM?

[AZhitman]

Man, what i wouldn't give to get a hold of those headers for a week.

We (BRM) could replicate them in stainless or mild steel and add them to our product line (along with the soon-to-be-released catback.)

Chally, any chance you can pose the question to the ol' chap?

[Chally]

The headers are custom made & have special coating for heat etc, & are made of special metal, & it may not be a good idea to make & fit something that looks the same, as the under bonnet temps could get a bit high if done wrong, otherwise, give AGM an email & see if his designer likes the idea.