Boost spike?

[91talonawdtsi]

Ok so ive been having all kinds of problems with boost spike and drop. I bought one of those jdm engines. Problem is that when i go WOT the boost spikes almost to fuel cut which is over 20 psi and drops to 11psi then climbs to 14 or 16 and stays stable i bought one of those cheap ebay boost controller think that could be it. just did a boost leak test everythings good?

 

[LiquidX]

Ok so ive been having all kinds of problems with boost spike and drop. I bought one of those jdm engines. Problem is that when i go WOT the boost spikes almost to fuel cut which is over 20 psi and drops to 11psi then climbs to 14 or 16 and stays stable i bought one of those cheap ebay boost controller think that could be it. just did a boost leak test everythings good?

First off, why did you get a "JDM" motor? The only good thing on there is the RVR IM after you port the opening to 60mm and attach a 1g TB on it. Other than that, it's the same block and head.

If you don't have fuel, don't be going more than 14psi. Just disconnect your MBC and run stock wastegate pressure. What exhaust setup do you have and how long did your pressure last for the boost leak test and what PSI did you pressurize it up to?

 

[dsmdeliveryboy]

What are your mods?

 

[91talonawdtsi]

My exhaust is a three inch cat back and 14 psi? i can run up to 19 without hitting cut. its over 20 where i run into problems. my mods list is pretty up to date.

 

[LiquidX]

My exhaust is a three inch cat back and 14 psi? i can run up to 19 without hitting cut. its over 20 where i run into problems. my mods list is pretty up to date.

If your fuel is stock and you don't have a tuning device, don't run more than 14/15 psi PERIOD. It doesn't matter if you hit fuel cut or not. You are going extremely lean regardless. Drop the boost down to 14psi or less!

You will damage your motor, I'm not surprised you have issues over 20psi. Not to mention anything after 16psi on the stock T-25 is out of it's efficiency range and you are only pushing hot air and over working the turbo which will shorten the life span as well.

 

[91talonawdtsi]

the turbo im running is a tdo4hl it flows the same as a 14b. and im running a front mount intercooler so it isnt all hot air.

 

[dawid4444]

but you damage your motor !!!!!! with stock motor, stock fuel system and no tuning with 19psi YOU ARE DAMAGE YOUR ENGINE !!!!
turn it down to 16psi MAXX !!

just my opinion

 

[dsmdeliveryboy]

but you damage your motor !!!!!! with stock motor, stock fuel system and no tuning with 19psi YOU ARE DAMAGE YOUR ENGINE !!!!
turn it down to 16psi MAXX !!

just my opinion

I wouldn't even run 16psi without a logging device and wideband, you always need to monitor your engine whenever you add boost because every motor reacts different weather you can tell or not. Your probably getting all kinds of knock as well, which will blow your car up. No offense, but don't ruin your car because your too cheap to turn up boost the right way. In the end you'll be much happier I promise. If you'd like, I'll have some RC 550's and a SAFCII up for sale soon. If you PM me we can work something out, they would be perfect for what turbo your running.

 

[JusMX141]

the turbo im running is a tdo4hl it flows the same as a 14b. and im running a front mount intercooler so it isnt all hot air.

Just for the record, there are no TD04/H/HL turbos that offer the same or greater flow potential than a TD05H turbo. Your turbo's compressor might brush the same compressor efficiency as a 14B for a split second, but the 14B has a higher flowing turbine housing / wheel and will support higher boost than anything in the TD04/H/HL frame.

If you'd like, I'll have some RC 550's and a SAFCII up for sale soon.

You can recommend the AFC2 and 550's then contact the O.P. regarding the sale, you can't use the forums to promote the sale of items you may *eventually* sell.

 

[91talonawdtsi]

ok well according to mitsubishi the tdo4hl-13t flows almost the same as a 14b? i do have logging software im running evo scan. would i even need safc since i have the 99 ecu?

what i was really wanting to know is why cant i run up to a set boost amount and stay there? Is it the cheap mbc?

 

[91talonawdtsi]

Ok it was the cheap MBC. Bought a Hallman and every thing runs great. Turned boost down to 15 just to be safe.