help, why as i go near redline i drop more boost?????????????????????
09-07-2003, 07:27 PM
#1
Thread Starter
Join Date: Jul 2003
Location: Pickering, ON, Canada
Posts: 149
Likes: 0
Received 0 Likes
on
0 Posts
help, why as i go near redline i drop more boost?????????????????????
Ok first when i floor it and get on the boost, it shoots to 7.5-8psi depending on load and ****.. then it levels out around 7psi then 6.8 or so.. then as i approach redline it goes to around 5.5 5.3 psi!!
why the hell is it dropping like that? what is the cause???
ihi rhb5 internal wastegated turbo
why the hell is it dropping like that? what is the cause???
ihi rhb5 internal wastegated turbo
09-07-2003, 07:30 PM
#3
Honda-Tech Member
Join Date: Jan 2002
Location: Prescott Arizona
Posts: 4,426
Likes: 0
Received 0 Likes
on
0 Posts
Re: help, why as i go near redline i drop more boost????????????????????? (reignofchaos)
sounds like your turbo is running out. I dont know much about that turbo, is it small?
Rob
Rob
09-07-2003, 07:34 PM
#4
Thread Starter
Join Date: Jul 2003
Location: Pickering, ON, Canada
Posts: 149
Likes: 0
Received 0 Likes
on
0 Posts
Re: help, why as i go near redline i drop more boost????????????????????? (rjardy)
how can it be? it is actuated at 8psi on the subaru and the subaru has a bigger engine than mine!!
09-07-2003, 07:39 PM
#5
Join Date: Aug 2003
Location: ...727...
Posts: 131
Likes: 0
Received 0 Likes
on
0 Posts
Re: help, why as i go near redline i drop more boost????????????????????? (reignofchaos)
Are your redlines comparable? It's not totally about the size of the engine, it's about flow. I'd imagine the subaru probably does flow more, but it may not. Has it always done this, or did it work previously?
09-07-2003, 07:46 PM
#6
Thread Starter
Join Date: Jul 2003
Location: Pickering, ON, Canada
Posts: 149
Likes: 0
Received 0 Likes
on
0 Posts
Re: help, why as i go near redline i drop more boost????????????????????? (94TurboGSR)
dunno, i think it always done this... i'm not really sure... you think it'll help if i change my wastegate line right at the manifold or at least after the IC?? it's right now connected to the stupid compressor housing.
Trending Topics
09-07-2003, 08:21 PM
#8
Honda-Tech Member
Join Date: Jan 2002
Location: Prescott Arizona
Posts: 4,426
Likes: 0
Received 0 Likes
on
0 Posts
Re: help, why as i go near redline i drop more boost????????????????????? (94TurboGSR)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94TurboGSR »</TD></TR><TR><TD CLASS="quote">If your turbo is dropping off then nothing is going to help. You need a bigger turbo.</TD></TR></TABLE> 
09-07-2003, 08:48 PM
#9
Thread Starter
Join Date: Jul 2003
Location: Pickering, ON, Canada
Posts: 149
Likes: 0
Received 0 Likes
on
0 Posts
Re: help, why as i go near redline i drop more boost????????????????????? (rjardy)
can you explain why? i don't understand
if i only want 7psi and the turbo can make it at 3000rpm, at higher rpm, why would it make it?? i understand if i want like 30psi it won't, but it's just the SAME psi!!
why wouldn't it make it? shouldn't the engine flow more at higher rpm?
if i only want 7psi and the turbo can make it at 3000rpm, at higher rpm, why would it make it?? i understand if i want like 30psi it won't, but it's just the SAME psi!!
why wouldn't it make it? shouldn't the engine flow more at higher rpm?
09-07-2003, 09:24 PM
#10
Honda-Tech Member
Join Date: Feb 2003
Location: Oregon
Posts: 3,219
Likes: 0
Received 0 Likes
on
0 Posts
Re: help, why as i go near redline i drop more boost????????????????????? (reignofchaos)
When I switched my line from the turbo to the intake manifold it lessened the boost drop on my greddy kit at higher rpm's. Worth a try. But yea, with a smaller turbo it's still going to drop off..
09-08-2003, 04:58 AM
#13
Honda-Tech Member
Join Date: Aug 2002
Location: Central NJ
Posts: 4,101
Likes: 0
Received 0 Likes
on
0 Posts
Re: help, why as i go near redline i drop more boost????????????????????? (reignofchaos)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by reignofchaos »</TD></TR><TR><TD CLASS="quote">still explain to me why</TD></TR></TABLE>
Because the TURBO IS SMALL, FUZZY NUTS. You need to listen more. lol. It just can't carry boost all the way to redline.
Because the TURBO IS SMALL, FUZZY NUTS. You need to listen more. lol. It just can't carry boost all the way to redline.
09-08-2003, 07:15 AM
#14
Member
Join Date: Mar 2002
Location: Dallas Sewers, Usa
Posts: 6,018
Likes: 0
Received 0 Likes
on
0 Posts
Re: help, why as i go near redline i drop more boost????????????????????? (Happyman)
Its the exchange of having a quick spooling turbo. Its just liek bigger turbo that have a bit of lag. Theres a price for everything
09-08-2003, 07:50 AM
#15
Honda-Tech Member
Join Date: Jan 2002
Location: DF Dub, TX, USA
Posts: 1,941
Likes: 0
Received 0 Likes
on
0 Posts
Re: help, why as i go near redline i drop more boost????????????????????? (quikB18B)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by quikB18B »</TD></TR><TR><TD CLASS="quote">Its the exchange of having a quick spooling turbo. Its just liek bigger turbo that have a bit of lag. Theres a price for everything </TD></TR></TABLE>
I found that perfect medium...
I found that perfect medium...
09-08-2003, 07:53 AM
#16
Re: help, why as i go near redline i drop more boost????????????????????? (reignofchaos)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by reignofchaos »</TD></TR><TR><TD CLASS="quote">can you explain why? i don't understand
why wouldn't it make it? shouldn't the engine flow more at higher rpm?</TD></TR></TABLE>
The engine consumes air. As you near your redline, the engine consumes more air than the turbo's producing, meaning the backlog of air - boost - is getting used up faster than the turbo can spool. That's because it's a smaller turbo.
why wouldn't it make it? shouldn't the engine flow more at higher rpm?</TD></TR></TABLE>
The engine consumes air. As you near your redline, the engine consumes more air than the turbo's producing, meaning the backlog of air - boost - is getting used up faster than the turbo can spool. That's because it's a smaller turbo.
09-08-2003, 08:07 AM
#17
Join Date: May 2003
Location: Albany, NY, USA
Posts: 75
Likes: 0
Received 0 Likes
on
0 Posts
Re: help, why as i go near redline i drop more boost????????????????????? (raene)
that's awfully low boost to run out of efficieny. I would look to the wastegate. If it is wastegate related, maybe a manual bc could serve as a bandaid?
09-08-2003, 08:39 AM
#18
Honda-Tech Member
Join Date: May 2003
Location: Santa Rosa, CA, USA
Posts: 1,075
Likes: 0
Received 0 Likes
on
0 Posts
Everyone is so concerned with how many pounds at what rpm. I think you have to look at how many ci at what rpm range you are running. A td05h and a t3 both set at 7 pounds are entirely diferent animals. One has a lot more flow at 7 pounds than the other. Get a bigger turbo and it won't drop off as fast at higher rpm levels. It won't spool up as fast either though. It all depends where you want your power band. I took off my t3 and went to the td05h cuz I needed boost at a lower rpm range. You just have to find that balance in your turbo selection.
09-08-2003, 10:38 AM
#20
Member
Join Date: Jan 2002
Location: Soon to be Phoenix, AZ, US
Posts: 1,063
Likes: 0
Received 0 Likes
on
0 Posts
Re: (raene)
So a t3 could have problems holding 7-8 lbs of boost all the way to say 8200 rmps??? That really suprises me. I thought they could at least do that.
09-08-2003, 05:07 PM
#22
Thread Starter
Join Date: Jul 2003
Location: Pickering, ON, Canada
Posts: 149
Likes: 0
Received 0 Likes
on
0 Posts
Re: (R6Elmo)
yeah 2.25 exhaust and stock cat
2.5 DP
how about a boost controller that will up the boost during higher rpms?
like i'm sure 7psi is not coming close to the surge limit of the turbo... i know for a fact that a ihi rhb5 can do at LEAST 12psi... so a boost controller can up the boost by closing the WG longer at higher rpm so it'll stay at 7-8 psi.. am i correct?
if i pull the vacuum line off my turbo, don't tell me it won't boost like up to 15-20psi even at redline.. i'm sure with the WG closed, it'll go up at least to 12-15 near redline (my redline is 7k, i have a sohc)
2.5 DP
how about a boost controller that will up the boost during higher rpms?
like i'm sure 7psi is not coming close to the surge limit of the turbo... i know for a fact that a ihi rhb5 can do at LEAST 12psi... so a boost controller can up the boost by closing the WG longer at higher rpm so it'll stay at 7-8 psi.. am i correct?
if i pull the vacuum line off my turbo, don't tell me it won't boost like up to 15-20psi even at redline.. i'm sure with the WG closed, it'll go up at least to 12-15 near redline (my redline is 7k, i have a sohc)
09-08-2003, 07:36 PM
#23
Re: (reignofchaos)
If you are losing boost at high RPMS, you wastegate isnt even open.
7psi refers to the amount of pressure in the intake manifold at your maximum amount of boost before a signal is sent to the wastegate to open.
If you are at a high RPM, as stated before, your car is sucking in more air than your turbo is producing, thus the boost goes down.
I say ditch the stock cat...that could definitely be one contributor and check and make sure the rest of your exhaust isnt clogged up somewhere. If the turbo cant let exhaust gases out, it cant push fresh air in.
Is the car tuned as well...maybe you are having problems with fuel up top? I dont exactly know if that would correlate to boost drop off though...
7psi refers to the amount of pressure in the intake manifold at your maximum amount of boost before a signal is sent to the wastegate to open.
If you are at a high RPM, as stated before, your car is sucking in more air than your turbo is producing, thus the boost goes down.
I say ditch the stock cat...that could definitely be one contributor and check and make sure the rest of your exhaust isnt clogged up somewhere. If the turbo cant let exhaust gases out, it cant push fresh air in.
Is the car tuned as well...maybe you are having problems with fuel up top? I dont exactly know if that would correlate to boost drop off though...
09-08-2003, 08:12 PM
#25
Honda-Tech Member
Join Date: Jul 2003
Location: Santa Clara, CA
Posts: 640
Likes: 0
Received 0 Likes
on
0 Posts
Re: (reignofchaos)
I really don't think a boost controller is going to help you to increase the boost. The limiting factor here isn't your method of boost controller. Your wastegate seems to stay closed here, it's teh ability for the turbo to flow. If the CAT is really old, it can be clogged (especially from a rich running car). This would hinder the performance of your car immensely.
Danny
Danny