Dynoed car, dissapointed.

[kaane]

I dynoed my car today, It seems I am missing about 20HP. Car seems to run fine, it's just not as strong as it should. Motor has great compression. What should I look for to find my missing HP? Plugs look ok, Timing set to 15. Any suggestions welcome

Mods
1989 240SX
Redtop SR motor
HKS downpipe
straight pipe
JIC 3 inch exhaust
Blitz SUS intake
Blitz DD bov
Walbro 255HP Fuel Pump
Stock side mount
12 PSI boost.

http://www.trnetworksolutions.com/dyno1.jpg

[Bill Roberts]

Port and polish the intake and head, bowl polish and port as well. 50 more HP.


I know, you got to tear it down, but worth it.


Valves are probably dirty on the back side, run techron to clean them, wear the engine in, to our type fuel...change the oil 3 times in 1500 miles.

Loosten it up some and make damn sure, your pipes to your exhaust flanges match. If you have some hard flat flange surfaces in your pipe matching, this kills power.


Actually those numbers are not bad. RWHP will be 15 to 20 off from the shaft rating.

Bet you can run a 14.4 right now..

The car is feeling good at least eh?

[oberkill]

I got 193 HP out of a similar setup running less boost so something is wrong.

I got over 200 hp on a similar setup with just a FMIC and no BOV at stock boost as well.

So I dont think he needs to upgrade to find the HP!

I am not sure what the issue is but give your turbo a good looking over. Also check to see if your BOV is leaking. May want to look at timing again as well.

Its really hard to diagnose a problem over the internet. Is there anyone local to you that may have some experiance working on SR's? Or any turbo car for that matter. If there is see if they have any ideas after looking at it.

Alan

[aeontony]

It has to be a boost leak..do you have a boost meter? The Blitz DD is suspect. Does your car stutter or anything when you drive it around? At 12 PSI it should be doing much more than that.

[boro240]

yeah that looks closer to bone stock SR.

[Jsquared]

1989 240SX
Redtop SR motor
HKS downpipe
straight pipe
JIC 3 inch exhaust
Blitz SUS intake
Blitz DD bov
Walbro 255HP Fuel Pump
Stock side mount
12 PSI boost.
those are the problems. i'm getting rid of my Blitz BOV as soon as I can afford to :mad:

[TheSparo]

is it healthy to run 12psi on the stock SMIC? i would turn it down to like 9 or 10... but thats my opinion

[kaane]

I wish I could turn it down, with 3inch exhaust and downpipe, I am running 12psi with no boost controller, using stock actuator.

[[GoaTSLonG]]

i have basically the exact same setup, 3" dp, 3" test pipe, 3" exaust, blitz SS BOV, stock sidemount, intake, and a fuel pump on my redtop and with no boost controller i dont ever go past 9, why does yours boost so high?

[s13chica]

First off...I read an article in import tuner about dynoing cars. They took the same car to five different dyno locations in one day. Every time they dynoed it they got a variety of number, which is expected. What they were suprised about was how different the numbers ranged. From the dyno with the lowest hp to the one with the highest was a 45hp difference. AND THAT WAS IN THE SAME DAY! So maybe you just need to take it to another spot.

It also sucks that you have the smic and you are running 12 pounds of boost. I have a large fmic and I still won't run over 11.5. I know it's an expensive part but you might want to think about investing in one so that your car doesn't blow up.

[Cramadon02]

this is kinda off topic. but since you have an sr already in, i was just wondering what you plan on doing when u need to renew your smog. right now i have an '89 240 hatch, and i'm really debating on an sr. any help would be appreciated. Thanks.

[Yoshi]

Originally posted by Cramadon02
this is kinda off topic. but since you have an sr already in, i was just wondering what you plan on doing when u need to renew your smog. right now i have an '89 240 hatch, and i'm really debating on an sr. any help would be appreciated. Thanks.

ok, I'll be nice since others wont.
1) DON'T hijack posts, everyone hates that
2) use the SEARCH button (red at the upper right) this has been discussed TONS
3) short answer to your question, if you're AT ALL worried about smog, then SR isn't for you.

Returning to the topic at hand...
I'm running a much similar setup at stock boost, and I NEVER boost over 8... I've hear Blitz BOV's are the suck ;)

[steve shadows]

I have been working with kaane and we have gotten his turbo rebuilt with a larger turbine housing as well as installed a hks fmic he purchased and an hks actuator. we should have the car runing this weekend then back to the dyno for him i assume.

Their are many limiting factors for sr20det motors espcially when using the stock actuator, ic and other variables, their could numerous unknown vacum leaks espeicallly in the smic, the car could have dirty combustion chamber or it could be as simple as old plugs. 175 whp would be good for a stock sr20det redtop.

obviously upgrading to a fmic and the fuel pump should be firsts as well as a preliminary leak down test and compression test. I do them on every motor i run across if im working on it.

[chineseb0i]

just reading on ur mods alone..the stock side mount aint gonna do. It looks likes u have upgraded fuel with the fuel pump but how about air? you might be running too rich possibly since you don't have n e thing to compensate for the fuel. 12 pounds of boost is a lot..i'd get a front mount intercooler like s13chica said and an intake and other things. And if that doesn't help, i think u should take it to another dyno..so many dyno's with so many numbers..:hammer:

[speeddreamz]

i turned out 203 hp 195 torque
on 7psi, 3in downpipe , greddy fmic, hks intake. No exhaust, no cat

[The Mole]

http://www.secretservicesinc.com/phm.html

this is johns car...where mattback hides out at
stock turbo

[kazuo]

What kind of dyno was it? DynoJet and other types of Dyno's give wildly varying numbers. Read Vishnu Tuning's article if you want more info (Google their site, I forget the address).

Anyway, as far as the "missing 20 HP" goes, I dunno what to tell you... my buddy dyno'd @ 180 and he had stock everything (Stock recirc, stock sidemount and running 7PSI on stock turbo) except for a 3" Random Tech cat and a HKS Hiper exhaust (80mm).

My best guess is that atmopsheric BOV and the Walbro are futzing with things (that's a good combination to make your car pee gasoline) and/or the sidemount with 12PSI (I've been told the most you want to even try with it is 10)

Anywho, yeh, dynotuning is in order. ;p

Good luck

[SX_Drifter]

These guys are right about the Blitz BOV and that stock side mount.

Since you said you don't have a boost controller, I'd look into getting one, TurboXS makes some good manual ones and they aren't to pricey. I'd also look to TurboXS for a different BOV.

Last definataly upgrade to an FMIC as soon as you can. I'd be a afaird to push that much boost with the stock side mount.

[240_keyy]

Hmmm, interesting that you dynoed so low...

About 3 months ago I dynoed my car in 95* weather here in Texas and it made 204hp and 221.3tq @ 10psi with the same mods as you except for a FMIC.

maybe the dyno is off or your IC is teh suck. I compared our curves, and they look identical except yours is dropped down like 25hp across the board...

[turboex]

my sr redtop with just intercooler exhaust and bov mad 185hp and 190tq at just 7psi, whats your compression readings?

[autobahNESSA]

Anyway, as far as the "missing 20 HP" goes, I dunno what to tell you... my buddy dyno'd @ 180 and he had stock everything (Stock recirc, stock sidemount and running 7PSI on stock turbo) except for a 3" Random Tech cat and a HKS Hiper exhaust (80mm).

Actually its a 2.5 inch random tech cat- 3in tend to blow out, I had gottent he cat when i was still na. ya and the hiper is 80mm i think, close to like 2.75 inch.

Im on 17" wheels, and it put down 181hp. 176 ftlbs. torque.

Yea 12 psi is a lot of air to push through that small ic.
try and run no more then 10 id say. either Fmic, or a larger smic would do the bill of allowing you to run 12psi.
What brand dyno did you use?
you may need to replace your actuator if your running 12psi.

[autobahNESSA]

your graph is really bouncy in the 4k and above. Mine was a lot smother. I think you do have a slight leak.
Id suspect your bov. put back on stock recirc. valve and dyno again. see what happens.

[autobahNESSA]

http://www.zilvia.net/f/showthread.php?s=&threadid=32410&perpage=30&highlight=dyno%20meet&pagenumber=3

theirs the link
on the page is my dyno graph.

if link doesnt work
search:
norcal dyno day
pg. 3

[steve shadows]

kaane is now usig an hks fmic and 550cc injectors along with an upgraded t25 turbo.

new dyno should be posted within a month

[kazuo]

Originally posted by speeddreamz
i turned out 203 hp 195 torque
on 7psi, 3in downpipe , greddy fmic, hks intake. No exhaust, no cat

And your car sounded like a fuckin rocket ship trying to escape the atmosphere... that shit was LOUD dude! ;p~

And don't forget the bag of ice we bought you. Not that it made a difference. ;)

How're the Z Brakes doin? ;P

[Joel 180]

Looks fine to me.
SR's will differ up to 30hp in power simply due to the fact that they are old engines and have been treated differentlty. Different brand Dynos will give different results too.

[Negreac]

What's wrong with the Blitz DD? SCC did a comparison and it did pretty well.

[uiuc240]

there is nothing wrong with it. it's a piston type BOV, so it leaks air when you use it. on a car with MAP controls, this isn't a problem. on cars like ours, with MAF sensors, this can screw up fuel mixture and driveability. i have one, but it's recirculated like shown in the attached picture.

Eric

[turboex]

I run the blitz dd open and its no problem for me, you just have to have the adjustment down a bit tighter so it does not leak. greddys work the same way too.

[uiuc240]

That works too, but it doesn't let all the air out between shifts, causing the CHH CHHH CHHHUUUUFFF sound. This is akin to having no pressure relief valve at all and relatively harsh on the turbo. I had mine like this for a while and didn't like the idea of it beating up my turbo so I recirculated it. Actually the MAIN reason I did it was because I was tired of it leaking MAJOR air at part throttle on the freeway. :bash:

Eric

[turboex]

On mine its just tightened a tad bit, the valve still opens just fine. I dont have any drive abilit probs and the valve stays open untill all the air is out. what valve are you using?

[blu808]

I bet you anything it was the outside temp.
If you look at your dyno sheet it said it was over 90f, that combined with the stock ic could be your problem. Especially if you have your boost turned up. The heat from the extra boost combined with the ambient air temp + a stock intercooler = crappy performance.

Seriously.
Luke

[nismofeind]

first your power isn't as smooth as it could be in boost, maybe a boost leak, timing, or spark plugs. Running 12psi on a stock smic is far beyond its efficiency. This is what really killed your numbers you were pushing super hot air in to your engine, especially on a 90f degree day. Actually lowering your boost on the smic would help you, doesn't matter now.

The DD leaks because its a dual drive, it has 2 pistons, unlike most others that have one large one. The first piston opens with light spring large one opens with large spring. Light spring is easier to open, so it leaks through the small first piston.

[CornerHard]

Build one of these (I only spent about $5 on mine and found some holes in my intercooler) and test for boost leaks in your intake system. It's really easy for pipes to be a bit loose, gaskets to go bad, etc:

http://www.vfaq.com/mods/ICtester.html