GTASHARK

Mark K, do you have any pictures of your vented airbox?

mark kibort

all take one, but here is what it kind of looks like.

danglerb

I don't argue with time slips, more MPH at the trap is more HP at the wheels.

Why maybe takes some testing and measuring to figure out. AFR logging, measuring manifold pressure and temperature, gotta be something going on.

GTASHARK

Thanks Mark. Interesting setup

mark kibort

lot of other variables going on with a drag run. More mph at the trap is that more HP was put to the ground for more time, but that can be effected by driver consistancies too, as well as a few other factors. a dyno is a simple tool.
It should be used, plus any engineerig reasons why this particular intake would run better HP than the stock stuff, with a similar filter material. (stock stuff is restrictive, and the air boxes leak and draw in Hot air, and all this needs to be controlled, as I have done in my dyno testing. (along with pressure sensing at different points in the intake, and flow bench results)

mark kibort

that might be a good design, dont you think. It will fit. just need a few mods.

did you see my inlets to the stock air box. yes, inlet guide vanes .

GTASHARK

Several years ago I did some testing based on Don Hanson's vented airbox, but it didn't have the inlet vanes. Results were good when in motion, but sucked in hot air from the engine bay when stopped.

From the pic it looks like you had to make some cuts to fit it in. I don't suppose there is any way to do it on a street car to avoid cutting?

Drewster67

Man I wish I had some dyno runs from before and after.

I do know this, before my CAI was installed. On the back straight of Firebird main, I was lucky if I got 125 mph before I had to let off to turn into turn 1. After the cold air intake was installed, Im pushing a 130-135. Thats what I mean by "woke up" Plus the sound of the air intake sucking air at the base my winshield sounds awesome. 2 thumbs up ...

inactiveuser1

Roger tested the Cold air intake with Y pipe on the dyno gave more HP that was the one simple check.

I think DR tested his Cold air intake with Y pipe on the dyno gave more HP also.

Testing at the track is also needed as more horsepower can be on top and less on bottom and overall ET may not change.

Tested mine at track and never reached the higher MPH with stock air intake with many runs.Most runs with stock air box was 77mph+ but under 78mph.

Test were done in afternoon and also in evening with cooler temps and still the stock air box couldn't reach the MPH even on a colder day.

Cold air intake mostly in 79+mph and close to 80mph even on a hot day.

Driver consistancies:car is an automatic leaves the line at same rpm every run.Used time slips where car didn't spin only gets into 2nd gear not many variables.
Clock doesn't start till you break the beam so reaction time has nothing too do with ET or MPH.

The stock air box thou sealed up better than stock like you are doing may work well also.

danglerb

A dyno is a simple tool, just not one for measuring HP, at least no chassis dyno I've ever heard of. They are very handy for certain kinds of tuning, but seems like these types of intake mods are not one of them.

This doesn't mean I don't want to know the why and how of this intake, the pressures and temperatures etc, but disagreement with some dyno results isn't even all that interesting to me, just another dyno flaw run.

mark kibort

Its a thinking mans game too. dynos VERY accurately measure hp. more accuratly than anything else you can do, especially engine dynos, which have removed all the lossey stuff.

the reason, it measures the rate of change of kinetic energy. no cheating that. that by defition IS HP. now, the only thing that it doesnt do, is measure hp dynamically where ram is effected. 2 factors are present there. ram effec and engine cooling. However, big fans during a dyno run can simulate that kind of cooling to keep the engine from getting cooked and killing HP. also, many dyno runs are done with the engine bay open, there is varience there. air box leaks dont really simulate the air boxes capabilities, due to hot air being brought in at the seams. Ive seen 5hp changes, that that are repeatable, just by positioning cold intake tubes around the engine bay.

the dyno is very repeatable , if nothing else changes. Ive been doing100s of them for 15 years and have never been surprised. I run the same process for every dyno I do. warm up, computer adjusted with lots of running time, and same engine oil and water temps for each run. even the runs are done the same to illiminate certain factors that can effect the run. (how you press the gas, what rpm you start at , etc) even with all this experience, we still get varience, because the system is not perfect. I would not look at just two runs, one done a week later, and say that a 10hp difference is due to a modification. ive had runs with NO changes that can do this. i was getting 315 to 325rwhp for years on the holbert car. always really, in the 320hp range. but, during the dyno run day, i could make changes ,and pull them off and the runs were mirror images of themselves time after time. this is the point.
Sure, DR did some testing, a few runs and possibly there are gains there vs the stock system. we wont know until we do a test as I have suggested what the real difference is. I am dying to know, personally.
But, if you look at how I have vented the air box. with huge holes in the rear, sealed to the base of the windshield area, you can see that several things are happening. we are getting RAM effect from the two front tubes, and near as high of pressure at the base of the windshield cavity, with openings as large as the front tubes. PLUS the air box is sealed, and doesnt leak or take in hot air , as most 928 intakes do. Again, I did tests to prove that this is what happens. this could be a huge factor in the results people have on dyno runs of KN vs stock. stock might force leaking more, give greater or equal results, but you are getting unfiltered air. that kind of thing.

Mk

mark kibort

Drewster, im sorry buddy, but your intake didnt do this. no way, no how, not phyiscally possible. I was doing these same speeds with the holbert car (at thunderhill with 320rwhpish) I would always get to 120, 125mph and that was at the edge of disaster for turn before braking. it wasnt until I bolted on another 1.5 liters to the engine (stroker 6.4L) giving me 60 more HP, was I able to get to 130mph down the main straight. (I think one time 140 with a very severe and unusual tail wind)
Lots of factors my friend, maybe now, with your experience there, you are hitting the last turn with greater vengance and that is what is giving you the higher Speed. better shifting also helps, this gets improved with experience too.
you have to realize. Ive done all these mods. played with the effects of small hp gains at the track (ie, intake, NOS, engine mods, timing, etc) and know very well their effects, all backed with video . everything here that has been said is strictly based on "feel". trust me, you cant trust "feel".

Ill buy ANY product that has been talked about here and double the price as a bonus if anything here would improve my hp , times, front straight speed, etc.
the first thing I have to ask you, is why it works? If you cant articulate why, then you are just guessing. sure, it all looks GREAT, but its voodo magic if it gains anything without the understanding of why.

Ive tested the intakes and used sensitive instuments to test pressure changes before and after and during. Ive done more controlled dyno testing and lots of hyway "dyno" runs with video taping the speedo for rates of speed changes. I can predict hp with it, not accurately, but certainly when something is wrong or improves.

Foget the dyno runs. give me some before and after 60 to 100mph in 3rd gear. video tape the speedo. this will be very valid and make my case, and show you if you are doing anything for the performance of your car.

Im sure the intake sounds awesome. scots little AFM through the firewall sounds great too. (you can hear it on the race video when I drove his car)
But, did you increase performance vs the stock air box. very hard to tell without some controllled tests. think about it. you have a 3.5" tube leading toward your CIS inlet with several turns and a single cone filter. you have to ask yourself, if I put that on a flow bench and also tested the stock set up with kn fitler, which would have the greatest pressure drop, and flow? remember, I used a powerflow flow bench to test open tubes, eram flow, on and off, etc. its very telling, because it is showing you the actual benifits or losses.
The eRAM is very useful for this kind of performance testing as I can accurately measure pressure , pressure loss and also motor RPM depending how I hook it up to the system. small changes in intake resistance give small changes to rpm output when backdriving the system with an eRAM simulating how the engine takes in air, and at near the same flow rates too. (ie. up to 800cfm)

If anyone is selling this stuff, and wants to get a valid test. I would pay double asking price for the unit if it works. Ill video tape the test, do it in a controled environment and do the test. until we do something like this, where it is somewhat controlled, its all "feel".

by the way NOONE is posting their HP numbers after the dynos. are they 10 to 20hp over what is normally found with your model and the other mods you have?? Probably not.

mark kibort

I certainly think the venting of the air box as I have it, is a little unfair to compare to the stock set up. what I have done, might equal what has been done by the cold intake system. dynamically, based on logic, what i have done is greatly open the air box all being fed by 4 openings , all the same size all being fed by high pressure zones with very little pressure loss.
my next dyno run session this season, will have to incorporate a sealed rear vent dyno run, as welll as the KN vs stock air filter run. I also want to run a clogged air filter run too, for Brian who might need a restrictor plate experiment result. (wrapping the filter in a t-shirt or some thin cloth)

Drewster67

Mark, All I can tell you is my factual experience. No Hype just my experience. As far as if there is a gain or how much of a gain if any at all, that mystery will never be solved because Im never going back to the stock air intake and stock tubing. I am not ruling out the experience curve - Ive been driving this shark for 5 seasona now and I know the car. I know what it did before the mod and I know what its doing after the mod.

Ask anyone who knows me, I drive my car pretty damn hard - The car pulls harder and I can reach a greater trap speed at the end of the straight. Simple as that -

One further bit of info - my shark is a Euro 85 with twin dizzy.

Its Ok to doubt but all I can tell you its my personal experience. Theres also no point in going back and forth on this as Its always good to have a civil debate - I just wish i had a few dyno runs in .....

Like I said in another post - I would love to go to Cali and run with a few of you guys either in HPDE4 or any TT's. (Car has no roll cage)

mark kibort

I believe you are seeing what you are seeing, but who knows the factors.
you have a euro with 85 motor so its hot wire, maybe fuel ratios changed a bit, maybe your old filter was a paper filter, (HMMMM?) maybe it had leaks, maybe , who knows. point is, you will only see those gains with huge HP change. (ie, 120 vs 135mph down a main straight)

I do agree, that intake problems will cause some significant losses. Just my last GTGP race, I forgot to clean out my air filter before the final race. I was way too lax that weekend, due to the rain. anyway, i was shifting out of third gear 100yards farther than usual. (go ahead and look at the rear view of the last few dry laps of the GTGP laguna race this year) then, look at video from laguna last year or even new engine '08 oct laguna. i was redlining much much earlier. i lost a hard fought battle with a pro GT3, in the race where first place in class was $1500 worth of tires!! ahhhhh! anyway, poored out the lb of sand out of the filter and the power cam back.

air box mods do work and are critical to flow for the MAF inlet too. It is too bad that you dont have any dyno runs from prior, or probably even remember the set up, but i would be you had stock air filter, probably not clean, probably had air leaks too. certainly, those factors alone could have made a big difference.

So, what was your HP when you dyno'ed it?? is it 20hp out of the ordinary vs others with the same car and stock intake? headers? I mean, if you dyno 290rwhp, with your euro, then you are probably getting gains over the stock intake I would guess. If you are 275-280, you may have gained a few hp, but who really knows. it looks great and sounds even better! Nice!

so what was your dyno hp anyway?
Mk